ORACLE DBA COMMANDS

1.USERADD : useradd is a command in Linux that is used to add user accounts to your system. It makes changes to the following files:

/etc/passwd
/etc/shadow
/etc/group
/etc/gshadow
creates a directory for new user in /home

	[root@sdbt ~]# useradd tesdbuser

	[root@sdbt ~]# cat /etc/passwd
	root:x:0:0:root:/root:/bin/bash

	bin:x:1:1:bin:/bin:/sbin/nologin
	daemon:x:2:2:daemon:/sbin:/sbin/nologin
	adm:x:3:4:adm:/var/adm:/sbin/nologin
	lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin

	sync:x:5:0:sync:/sbin:/bin/sync
	shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
	halt:x:7:0:halt:/sbin:/sbin/halt

	mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
	smmsp:x:51:51::/var/spool/mqueue:/sbin/nologin
	tesdbuser:x:54322:54335::/home/tesdbuser:/bin/bash

	[root@sdbt ~]# cd /home
	[root@sdbt home]# ll
	total 4

	drwx------.  3 tesdbuser     54331   92 Jun 29 16:44 krish
	drwx------. 22 oracle    oinstall  4096 Oct 18 16:50 oracle
	drwx------.  3 pgbouncer pgbouncer   92 May 26 14:37 pgbouncer
	drwx------.  3 sdbt      sdbt        78 Mar  1  2022 sdbt
	drwx------.  3 tesdbuser tesdbuser   92 Oct 20 17:46 tesdbuser

Creating user with comment:

	[root@sdbt home]# useradd -c "this is a test user" test_user
	[root@sdbt home]# cat /etc/passwd|grep test_user
	test_user:x:54323:54336:this is a test user:/home/test_user:/bin/bash

Creating user with expiry date:

	[root@sdbt home]# useradd -e 2023-11-30 test_user1
	[root@sdbt home]# cat /etc/passwd|grep test_user1
	test_user1:x:54324:54337::/home/test_user1:/bin/bash
	[root@sdbt home]# chage -l test_user1

	Last password change					: Oct 20, 2023
	Password expires					: never
	Password inactive					: never
	Account expires						: Nov 30, 2023
	Minimum number of days between password change		: 0
	Maximum number of days between password change		: 99999
	Number of days of warning before password expires	: 7

Creating user to a particular group:

	  [root@sdbt home]# useradd -g 0 test_user2
	  [root@sdbt home]# id test_user2
	  uid=54325(test_user2) gid=0(root) groups=0(root)
	  [root@sdbt home]#

2.USERMOD:
usermod command or modify user is a command in Linux that is used to change the properties of a user in Linux through the command line.
After creating a user we have to sometimes change their attributes like password or login directory etc. so in order to do that we use the Usermod command.
usermod command needs to be executed only as a root user.
2.1. To add a comment for a user

	[root@sdbt home]# usermod -c "this is test user" test_user2
	[root@sdbt home]# cat /etc/passwd|grep test_user2
	test_user2:x:54325:0:this is test user:/home/test_user2:/bin/bash

2.2 To change the expiry date of a user

	[root@sdbt home]# usermod -e 2023-12-31 test_user2
	[root@sdbt home]# chage -l test_user2

	Last password change		: Oct 20, 2023
	Password expires		: never
	Password inactive		: never

	Account expires	                                	: Dec 31, 2023
	Minimum number of days between password change		: 0
	Maximum number of days between password change		: 99999
	Number of days of warning before password expires	: 7

2.3 To change user login name

	[root@sdbt ~]# cat /etc/passwd|grep test_user2
	test_user2:x:54325:0:this is test user:/home/test_user2:/bin/bash

	You have new mail in /var/spool/mail/root
	[root@sdbt ~]# usermod -l test_user3 test_user2
	usermod: warning: /var/spool/mail/test_user2 not owned by test_user2

	[root@sdbt ~]# cat /etc/passwd|grep test_user3
	test_user3:x:54325:0:this is test user:/home/test_user2:/bin/bash
	[root@sdbt ~]#

3.USERDEL:
userdel command in Linux system is used to delete a user account and related files.
userdel -f: This option forces the removal of the specified user account. It doesn’t matter that the user is still logged in. It also forces the userdel to remove
the user’s home directory and mail spool, even if another user is using the same home directory or even if the mail spool is not owned by the specified user.
userdel -r: Whenever we are deleting a user using this option then the files in the user’s home directory
will be removed along with the home directory itself and the user’s mail spool.

	[root@sdbt ~]# cat /etc/passwd|grep test_user1
	test_user1:x:54324:54337::/home/test_user1:/bin/bash
	[root@sdbt ~]# userdel -r test_user1
	[root@sdbt ~]# cat /etc/passwd|grep test_user1
	[root@sdbt ~]#

4.CHOWN -R:
This option is used to apply the changes recursively.

	[root@sdbt ~]# cd tesdb
	[root@sdbt tesdb]# ll
	total 0

	[root@sdbt tesdb]# touch test1
	[root@sdbt tesdb]# ll
	total 0

	-rw-r--r--. 1 root root 0 Oct 21 11:04 test1
	[root@sdbt tesdb]# chown -R oracle:oinstall test1
	[root@sdbt tesdb]# ll
	total 0

	-rw-r--r--. 1 oracle oinstall 0 Oct 21 11:04 test1
	[root@sdbt tesdb]#

5.CHGRP:
The `chgrp` command in Linux is used to change the group ownership of a file or directory.

Changing Group Ownership of a Single File

	[root@sdbt ~]# ls -lrt|grep test_file
	-rw-r--r--. 1 root root       0 Oct 25 12:18 test_file
	[root@sdbt ~]# chgrp oinstall test_file
	[root@sdbt ~]# ls -lrt|grep test_file
	-rw-r--r--. 1 root oinstall       0 Oct 25 12:18 test_file
	[root@sdbt ~]#

Changing Group Ownership of Multiple Files

	

	[root@sdbt tesdb]# ls -lrt
	total 0
	-rw-r--r--. 1 oracle oinstall 0 Oct 21 11:04 test1
	-rw-r--r--. 1 oracle oinstall 0 Oct 25 12:37 test2
	[root@sdbt tesdb]# chgrp root test1 test2
	[root@sdbt tesdb]# ls -lrt
	total 0
	-rw-r--r--. 1 oracle root 0 Oct 21 11:04 test1
	-rw-r--r--. 1 oracle root 0 Oct 25 12:37 test2
	[root@sdbt tesdb]#

Using the groupname of a reference file

	[root@sdbt tesdb]# ls -lrt
	total 0

	-rw-r--r--. 1 oracle oinstall 0 Oct 21 11:04 test1
	-rw-r--r--. 1 oracle oinstall 0 Oct 25 12:37 test2
	-rw-r--r--. 1 root   root     0 Oct 25 12:41 test3
	[root@sdbt tesdb]# chgrp -R --reference=test3 test1 test2
	[root@sdbt tesdb]# ls -lrt
	total 0

	-rw-r--r--. 1 oracle root 0 Oct 21 11:04 test1
	-rw-r--r--. 1 oracle root 0 Oct 25 12:37 test2
	-rw-r--r--. 1 root   root 0 Oct 25 12:41 test3
	[root@sdbt tesdb]#

6. NETSTAT -PLUNT :
will show the Active Internet connections along with port number

	[root@sdbt tesdb]# netstat -plunt
	Active Internet connections (only servers)
	Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
	tcp        0      0 192.168.122.1:53        0.0.0.0:*               LISTEN      1722/dnsmasq
	tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      1132/sshd
	tcp        0      0 127.0.0.1:631           0.0.0.0:*               LISTEN      1114/cupsd
	tcp        0      0 0.0.0.0:5432            0.0.0.0:*               LISTEN      1146/postmaster
	tcp        0      0 127.0.0.1:25            0.0.0.0:*               LISTEN      1838/sendmail: acce
	tcp        0      0 0.0.0.0:111             0.0.0.0:*               LISTEN      667/rpcbind
	tcp6       0      0 :::22                   :::*                    LISTEN      1132/sshd
	tcp6       0      0 ::1:631                 :::*                    LISTEN      1114/cupsd
	tcp6       0      0 :::5432                 :::*                    LISTEN      1146/postmaster
	tcp6       0      0 :::111                  :::*                    LISTEN      667/rpcbind
	udp        0      0 192.168.122.1:53        0.0.0.0:*                           1722/dnsmasq
	udp        0      0 0.0.0.0:67              0.0.0.0:*                           1722/dnsmasq
	udp        0      0 0.0.0.0:111             0.0.0.0:*                           667/rpcbind
	udp        0      0 0.0.0.0:5353            0.0.0.0:*                           732/avahi-daemon: r
	udp        0      0 0.0.0.0:840             0.0.0.0:*                           667/rpcbind
	udp        0      0 0.0.0.0:26548           0.0.0.0:*                           732/avahi-daemon: r
	udp6       0      0 :::111                  :::*                                667/rpcbind
	udp6       0      0 :::840                  :::*                                667/rpcbind
	[root@sdbt tesdb]#

7.IPCS :
ipcs shows information on the inter-process communication facilities for which the calling process has read access. By default, it shows information about
all three resources: shared memory segments, message queues, and semaphore arrays.
Without options, the information shall be written in short format for message queues, shared memory segments, and semaphore sets that are currently active
in the system

7.1 To list all the IPC facility.All the IPC facility has unique key and identifier, which is used to identify an IPC facility

	[root@sdbt tesdb]# ipcs -a

	------ Message Queues --------
	key        msqid      owner      perms      used-bytes   messages

	------ Shared Memory Segments --------
	key        shmid      owner      perms      bytes      nattch     status
	0x040928db 0          postgres   600        56         6
	0x00000000 10         root       777        16384      1          dest
	0x00000000 11         root       777        1310720    1          dest
	0x00000000 19         root       600        524288     2          dest
	0x00000000 23         root       600        524288     2          dest
	0x00000000 24         root       777        3932160    2          dest
	0x00000000 25         root       777        3932160    2          dest
	0x00000000 29         root       600        16777216   2          dest
	0x00000000 34         root       600        524288     2          dest
	0x00000000 39         root       600        524288     2          dest
	0x00000000 40         root       777        3784704    2          dest

	------ Semaphore Arrays --------
	key        semid      owner      perms      nsems

7.2:To list all the Message Queue.It lists only message queues for which the current process has read access.

	[root@sdbt tesdb]# ipcs -q

	------ Message Queues --------
	key        msqid      owner      perms      used-bytes   messages

7.3 To list all the Semaphores

	# ipcs -s : To list the accessible semaphores.
	[root@sdbt tesdb]# ipcs -s

	------ Semaphore Arrays --------
	key        semid      owner      perms      nsems

7.4 To list all the Shared Memory

	# ipcs -m : To lists the shared memories.
	[root@sdbt tesdb]# ipcs -m

	------ Shared Memory Segments --------
	key        shmid      owner      perms      bytes      nattch     status
	0x040928db 0          postgres   600        56         6
	0x00000000 10         root       777        16384      1          dest
	0x00000000 11         root       777        1310720    1          dest
	0x00000000 19         root       600        524288     2          dest
	0x00000000 23         root       600        524288     2          dest
	0x00000000 24         root       777        3932160    2          dest
	0x00000000 25         root       777        3932160    2          dest
	0x00000000 29         root       600        16777216   2          dest
	0x00000000 34         root       600        524288     2          dest
	0x00000000 39         root       600        524288     2          dest
	0x00000000 40         root       777        3784704    2          dest

8.IPCRM:
ipcrm command in Linux is used to remove some IPC(Inter-Process Communication) resources. It eliminates the IPC objects and their associated
data structure form the system. One must be a creator or superuser or the owner of the object in order to remove these objects. There are three types of
System V IPC objects i.e. semaphores, shared memory, and message queues.
Options:
-a, –all [shm] [msg] [sem] : Remove all resources. When an option argument is provided, the removal is performed only for the specified resource types.
-M, –shmem-key shmkey : Remove the shared memory segment created with shmkey after the last detach is performed.
-m, –shmem-id shmid : Remove the shared memory segment identified by shmid after the last detach is performed.
-Q, –queue-key msgkey : Remove the message queue created with msgkey.
-q, –queue-id msgid : Remove the message queue identified by msgid.
-S, –semaphore-key semkey : Remove the semaphore created with semkey.
-s, –semaphore-id semid : Remove the semaphore identified by semid.
-V, –version : Display version information and exit

OUTPUT:

	[root@sdbt tesdb]# ipcrm -V
	ipcrm from util-linux 2.23.2

9. SYSRESV -
SYSRESV Utility which does map instances to shared memory segments. This utility can be used to both identify which shared memory segments
belong to which instances

OUTPUT:

	[oracle@sdbt ~]$ sysresv -l dev

	IPC Resources for ORACLE_SID "dev" :
	Maximum shared memory segment size (shmmax): 4398046511104 bytes
	Total system shared memory (shmall): 4398046511104 bytes
	Total system shared memory count (shmmni): 4096
	*********************** Dumping ipcs output ********************

	------ Message Queues --------
	key        msqid      owner      perms      used-bytes   messages

	------ Shared Memory Segments --------
	key        shmid      owner      perms      bytes      nattch     status
	0x040928db 0          postgres   600        56         6
	0x00000000 10         root       777        16384      1          dest
	0x00000000 11         root       777        1310720    1          dest
	0x00000000 19         root       600        524288     2          dest
	0x00000000 23         root       600        524288     2          dest
	0x00000000 24         root       777        3932160    2          dest
	0x00000000 25         root       777        3932160    2          dest
	0x00000000 29         root       600        16777216   2          dest
	0x00000000 34         root       600        524288     2          dest
	0x00000000 40         root       777        3784704    2          dest
	0x00000000 45         root       600        524288     2          dest
	0x00000000 46         root       777        3784704    2          dest
	0x00000000 47         oracle     600        8626176    129
	0x00000000 48         oracle     600        696254464  65
	0x00000000 49         oracle     600        8151040    65
	0x5a106d74 50         oracle     600        16384      65

	------ Semaphore Arrays --------
	key        semid      owner      perms      nsems
	0x9501bdcc 4          oracle     600        152
	0x9501bdcd 5          oracle     600        152
	0x9501bdce 6          oracle     600        152

	*********************** End of ipcs command dump **************


	***************** Dumping Resource Limits(s/h) *****************
	core file size                         0 KB/UNLIMITED
	data seg size                     UNLIMITED/UNLIMITED
	scheduling priority                    0 KB/0 KB
	file size                         UNLIMITED/UNLIMITED
	pending signals                        6 KB/6 KB
	max locked memory                    128 GB/128 GB
	max memory size                   UNLIMITED/UNLIMITED
	open files                            64 KB/64 KB
	POSIX message queues                 800 KB/800 KB
	real-time priority                     0 KB/0 KB
	stack size                            32 MB/32 MB
	cpu time                          UNLIMITED/UNLIMITED
	max user processes                    16 KB/16 KB
	virtual memory                    UNLIMITED/UNLIMITED
	file locks                        UNLIMITED/UNLIMITED

	***************** End of Resource Limits Dump ******************
	Maximum map count configured per process:  65530
	Total /dev/shm size: 887459840 bytes, used: 24576 bytes
	Shared Memory:
	ID		KEY
	48      	0x00000000
	49      	0x00000000
	47      	0x00000000
	50      	0x5a106d74
	Semaphores:
	ID		KEY
	4       	0x9501bdcc
	5       	0x9501bdcd
	6       	0x9501bdce
	Oracle Instance alive for sid "dev"
	[oracle@sdbt ~]$

10.HOSTNAME:
hostname command in Linux is used to obtain the?DNS (Domain Name System) name

10.1 `-a` Option in `hostname` command in Linux Display all aliases of the host.
OUTPUT:

	[root@sdbt ~]# hostname -a
	Sdbt

	[root@sdbt ~]# hostname -f
	sdbt.localdomain

10.2 - HOSTNAME -I: find ipadress

	  [root@sdbt ~]# hostname -i
	  192.168.1.101

11.IFCONFIG :
ifconfig(interface configuration) command is used to configure the kernel-resident network interfaces. It is used at the boot time to set up the
interfaces as necessary. After that, it is usually used when needed during debugging or when you need system tuning. Also, this command is used to
assign the IP address and netmask to an interface or to enable or disable a given interface.
OUTPUT:

	[root@sdbt ~]# ifconfig -a
	enp0s3: flags=4163  mtu 1500
	  inet 192.168.1.101  netmask 255.255.255.0  broadcast 192.168.1.255
	  inet6 2401:4900:1cc8:6ee0:1af4:7635:2bea:b189  prefixlen 64
	  scopeid 0x0

	  inet6 fe80::da9:9ed6:ea06:dd42  prefixlen 64  scopeid 0x20
	  ether 08:00:27:09:27:07  txqueuelen 1000  (Ethernet)
	  RX packets 51489  bytes 60497769 (57.6 MiB)
	  RX errors 0  dropped 0  overruns 0  frame 0
	  TX packets 7101  bytes 560624 (547.4 KiB)
	  TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

	lo: flags=73  mtu 65536
	  inet 127.0.0.1  netmask 255.0.0.0
	  inet6 ::1  prefixlen 128  scopeid 0x10
	  loop  txqueuelen 1000  (Local Loopback)
	  RX packets 1570  bytes 447009 (436.5 KiB)
	  RX errors 0  dropped 0  overruns 0  frame 0
	  TX packets 1570  bytes 447009 (436.5 KiB)
	  TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

	virbr0: flags=4099  mtu 1500
	  inet 192.168.122.1  netmask 255.255.255.0  broadcast 192.168.122.255
	  ether 52:54:00:d1:56:95  txqueuelen 1000  (Ethernet)
	  RX packets 0  bytes 0 (0.0 B)
	  RX errors 0  dropped 0  overruns 0  frame 0
	  TX packets 0  bytes 0 (0.0 B)
	  TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

	virbr0-nic: flags=4098  mtu 1500
	  ether 52:54:00:d1:56:95  txqueuelen 1000  (Ethernet)
	  RX packets 0  bytes 0 (0.0 B)
	  RX errors 0  dropped 0  overruns 0  frame 0
	  TX packets 0  bytes 0 (0.0 B)
	  TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

12. SYSTEMCTL START|STOP|STATUS|RESTART NETWORK:
Once you make changes in the server network configuration file, then require to restart the server networking service in order to reflect the changes.
OUTPUT:

	[root@sdbt ~]# systemctl status network
	? network.service - LSB: Bring up/down networking
	Loaded: loaded (/etc/rc.d/init.d/network; bad; vendor preset: disabled)
	Active: active (exited) since Wed 2023-10-25 09:32:55 IST; 3h 43min ago
	Docs: man:systemd-sysv-generator(8)
	Process: 913 ExecStart=/etc/rc.d/init.d/network start (code=exited, status=0/SUCCESS)
	Tasks: 0

	Oct 25 09:32:49 sdbt.localdomain systemd[1]: Starting LSB: Bring up/down networking...
	Oct 25 09:32:54 sdbt.localdomain network[913]: Bringing up loopback interface:  [  OK  ]
	Oct 25 09:32:55 sdbt.localdomain network[913]: Bringing up interface enp0s3:  [  OK  ]
	Oct 25 09:32:55 sdbt.localdomain systemd[1]: Started LSB: Bring up/down networking.
	[root@sdbt ~]# systemctl stop network
	[root@sdbt ~]# systemctl status network
	? network.service - LSB: Bring up/down networking
	Loaded: loaded (/etc/rc.d/init.d/network; bad; vendor preset: disabled)
	Active: inactive (dead) since Wed 2023-10-25 13:16:37 IST; 3s ago
	Docs: man:systemd-sysv-generator(8)
	Process: 30714 ExecStop=/etc/rc.d/init.d/network stop (code=exited, status=0/SUCCESS)
	Process: 913 ExecStart=/etc/rc.d/init.d/network start (code=exited, status=0/SUCCESS)

	Oct 25 09:32:49 sdbt.localdomain systemd[1]: Starting LSB: Bring up/down networking...
	Oct 25 09:32:54 sdbt.localdomain network[913]: Bringing up loopback interface:  [  OK  ]
	Oct 25 09:32:55 sdbt.localdomain network[913]: Bringing up interface enp0s3:  [  OK  ]
	Oct 25 09:32:55 sdbt.localdomain systemd[1]: Started LSB:Bring up/down networking.
	Oct 25 13:16:34 sdbt.localdomain systemd[1]: Stopping LSB:Bring up/down networking...
	Oct 25 13:16:36 sdbt.localdomain network[30714]: Shutting down interface enp0s3:
	Device 'enp0s3' successfully disconnected.

	Oct 25 13:16:36 sdbt.localdomain network[30714]: [  OK  ]
	Oct 25 13:16:37 sdbt.localdomain network[30714]: Shutting down loopback interface:  [  OK  ]
	Oct 25 13:16:37 sdbt.localdomain systemd[1]: Stopped LSB:Bring up/down networking.
	[root@sdbt ~]# systemctl start network
	[root@sdbt ~]# systemctl status network
	? network.service - LSB: Bring up/down networking
	Loaded: loaded (/etc/rc.d/init.d/network; bad; vendor preset: disabled)
	Active: active (exited) since Wed 2023-10-25 13:16:51 IST; 2s ago
	Docs: man:systemd-sysv-generator(8)
	Process: 30714 ExecStop=/etc/rc.d/init.d/network stop (code=exited, status=0/SUCCESS)
	Process: 30921 ExecStart=/etc/rc.d/init.d/network start (code=exited, status=0/SUCCESS)
	Tasks: 0

	Oct 25 13:16:50 sdbt.localdomain systemd[1]: Starting LSB: Bring up/down networking...
	Oct 25 13:16:51 sdbt.localdomain network[30921]: Bringing up loopback interface:  [  OK  ]
	Oct 25 13:16:51 sdbt.localdomain network[30921]: Bringing up interface enp0s3:Connection
	successfully activated(D-Bus active pa...tion/4)

	Oct 25 13:16:51 sdbt.localdomain network[30921]: [  OK  ]
	Oct 25 13:16:51 sdbt.localdomain systemd[1]: Started LSB: Bring up/down networking.
	Hint: Some lines were ellipsized, use -l to show in full.

13. MKDIR :
mkdir command in Linux allows the user to create directories (also referred to as folders in some operating systems). This command can create
multiple directories at once as well as set the permissions for the directories. mkdir -p :A flag which enables the command to create
parent directories as necessary. If the directories exist, no error is specified.
OUTPUT:

	
	[root@sdbt ~]# mkdir -p tesdb/tesdb1/tesdb2/tesdb3
	[root@sdbt ~]# ls -lrt
	drwxr-xr-x. 3 root root          34 Oct 20 14:44 test
	-rw-r--r--. 1 root oinstall       0 Oct 25 12:18 test_file
	drwxr-xr-x. 3 root root        4096 Oct 25 12:18 Pictures
	drwxr-xr-x. 3 root root          20 Oct 25 13:19 tesdb
	[root@sdbt ~]# cd tesdb
	[root@sdbt tesdb]# ls -lrt
	total 0
	drwxr-xr-x. 3 root root 20 Oct 25 13:19 tesdb1
	[root@sdbt tesdb]# cd tesdb1
	[root@sdbt tesdb1]# ll
	total 0
	drwxr-xr-x. 3 root root 20 Oct 25 13:19 tesdb2
	[root@sdbt tesdb1]# cd tesdb2/
	[root@sdbt tesdb2]# ll
	total 0
	drwxr-xr-x. 2 root root 6 Oct 25 13:19 tesdb3
	[root@sdbt tesdb2]# cd tesdb3/
	[root@sdbt tesdb3]# ll
	total 0
	[root@sdbt tesdb3]# pwd
	/root/tesdb/tesdb1/tesdb2/tesdb3
	[root@sdbt tesdb3]#

14. TAR:
The Linux ‘tar’ stands for tape archive, which is used to create Archive and extract the Archive files. tar command in Linux is one of the important commands
which provides archiving functionality in Linux. We can use the Linux tar command to create compressed or uncompressed Archive files and also maintain
and modify them.

14.1. Creating an uncompressed tar Archive using option -cvf
This command creates a tar file called file.tar which is the Archive of all .c files in the
current directory.

	  tar cvf file.tar
	  •	‘-c’: Creates a new archive.
	  •	‘-v’: Displays verbose output, showing the progress of the archiving process.
	  •	‘-f’: Specifies the filename of the archive

OUTPUT :

	[root@sdbt tesdb]# ls -lrt
	total 0
	-rw-r--r--. 1 root root 0 Oct 25 13:26 test3
	-rw-r--r--. 1 root root 0 Oct 25 13:26 test2
	-rw-r--r--. 1 root root 0 Oct 25 13:26 test1
	[root@sdbt tesdb]# tar -cvf file1.tar test*
	test1
	test2
	test3
	[root@sdbt tesdb]# ls -lrt
	total 12
	-rw-r--r--. 1 root root     0 Oct 25 13:26 test3
	-rw-r--r--. 1 root root     0 Oct 25 13:26 test2
	-rw-r--r--. 1 root root     0 Oct 25 13:26 test1
	-rw-r--r--. 1 root root 10240 Oct 25 13:27 file1.tar

14.2 Extracting files from Archive using option -xvf
This command extracts files from Archives.
tar xvf file.tar

‘-x’: Extracts files from an archive.

‘-v’: Displays verbose output during the extraction process.

‘-f’: Specifies the filename of the archive.

OUTPUT:

	[root@sdbt tesdb]# ls -lrt
	total 12
	-rw-r--r--. 1 root root     0 Oct 25 13:26 test3
	-rw-r--r--. 1 root root     0 Oct 25 13:26 test2
	-rw-r--r--. 1 root root     0 Oct 25 13:26 test1
	-rw-r--r--. 1 root root 10240 Oct 25 13:27 file1.tar
	[root@sdbt tesdb]# tar -xvf file1.tar
	test1
	test2
	test3
	[root@sdbt tesdb]#

14.3 Viewing the Archive using option -tvf
OUTPUT:

	[root@sdbt tesdb]# ls -lrt
	total 12
	-rw-r--r--. 1 root root     0 Oct 25 13:26 test3
	-rw-r--r--. 1 root root     0 Oct 25 13:26 test2
	-rw-r--r--. 1 root root     0 Oct 25 13:26 test1
	-rw-r--r--. 1 root root 10240 Oct 25 13:27 file1.tar
	[root@sdbt tesdb]# tar -tvf file1.tar
	-rw-r--r-- root/root         0 2023-10-25 13:26 test1
	-rw-r--r-- root/root         0 2023-10-25 13:26 test2
	-rw-r--r-- root/root         0 2023-10-25 13:26 test3
	[root@sdbt tesdb]#

15. GZIP:
gzip command compresses files. Each single file is compressed into a single file. If given a file as an argument, gzip compresses the file,
adds a ".gz" suffix, and deletes the original file.

-r option :
This option can compress every file in a folder and its subfolders.This option doesn’t create one file called foldername.gz.
Instead, it traverses the directory structure and compresses each file in that folder structure.
OUTPUT:

	[root@sdbt tesdb]# gzip -r tesdb1/
	[root@sdbt tesdb]# ll
	total 0
	drwxr-xr-x. 2 root root 38 Oct 25 13:43 tesdb1
	[root@sdbt tesdb]# cd tesdb1/
	[root@sdbt tesdb1]# ll
	total 8
	-rw-r--r--. 1 root root 26 Oct 25 13:42 test1.gz
	-rw-r--r--. 1 root root 26 Oct 25 13:42 test2.gz
	[root@sdbt tesdb1]#

-v option:
This option displays the name and percentage reduction for each file compressed or decompressed.

	[root@sdbt tesdb]# ls -lrt
	total 0
	drwxr-xr-x. 2 root root 38 Oct 25 13:43 tesdb1
	-rw-r--r--. 1 root root  0 Oct 25 13:45 tesdbfile
	[root@sdbt tesdb]# gzip -v tesdbfile
	tesdbfile:	  0.0% -- replaced with tesdbfile.gz
	[root@sdbt tesdb]# ls -lrt
	total 4
	drwxr-xr-x. 2 root root 38 Oct 25 13:43 tesdb1
	-rw-r--r--. 1 root root 30 Oct 25 13:45 tesdbfile.gz
	[root@sdbt tesdb]#

-d option :
This option allows to decompress a file using the "gzip" command

	[root@sdbt tesdb]# ls -lrt
	total 4
	drwxr-xr-x. 2 root root 38 Oct 25 13:43 tesdb1
	-rw-r--r--. 1 root root 30 Oct 25 13:45 tesdbfile.gz
	[root@sdbt tesdb]# gzip -d tesdbfile.gz
	[root@sdbt tesdb]# ls -lrt
	total 0
	drwxr-xr-x. 2 root root 38 Oct 25 13:43 tesdb1
	-rw-r--r--. 1 root root  0 Oct 25 13:45 tesdbfile
	[root@sdbt tesdb]#

Gunzip:
This option allows to extract a gzip file

	  [root@sdbt tesdb]# ls -lrt
	  total 4
	  drwxr-xr-x. 2 root root 38 Oct 25 13:43 tesdb1
	  -rw-r--r--. 1 root root 30 Oct 25 13:45 tesdbfile.gz
	  [root@sdbt tesdb]# gunzip tesdbfile.gz
	  [root@sdbt tesdb]# ls -lrt
	  total 0
	  drwxr-xr-x. 2 root root 38 Oct 25 13:43 tesdb1
	  -rw-r--r--. 1 root root  0 Oct 25 13:45 tesdbfile
	  [root@sdbt tesdb]#

16.top:
The top command is used to show the active Linux processes.

	  top - 13:54:27 up  4:22,  3 users,  load average: 0.05, 0.13, 0.16
	  Tasks: 283 total,   2 running, 224 sleeping,   0 stopped,   0 zombie
	  %Cpu(s):  6.5 us,  1.9 sy,  0.0 ni, 89.8 id,  0.3 wa,  1.5 hi,  0.0 si,  0.0 st
	  KiB Mem :  1733372 total,    24856 free,   858848 used,   849668 buff/cache
	  KiB Swap:  4194300 total,  3990780 free,   203520 used.   382392 avail Mem

	  PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND
	  ---------     --- --- ------- ------- ----- - ----- ----   ------------------
	  2717 root      20   0 3513196 161880  44012 S   9.0  9.3   1:28.68 gnome-shell
	  2064 root      20   0  353944  49604  23216 R   4.3  2.9   0:38.83 X
	  3516 root      20   0  674196  26196  13616 S   2.3  1.5   0:20.10 gnome-terminal-
	  27544 oracle   -2   0 1132620  15428  12776 S   1.3  0.9   0:45.47 ora_vktm_dev
	  2613 root      20   0  289416    896    844 S   0.7  0.1   0:20.79 VBoxClient
	  2876 root      20   0 1000400   6596   4532 S   0.3  0.4   0:00.42 gsd-power
		1 root       20   0  225292   8188   6100 S   0.0  0.5   0:05.48 systemd
		2 root       20   0       0      0      0 S   0.0  0.0   0:00.01 kthreadd
		3 root        0 -20       0      0      0 I   0.0  0.0   0:00.00 rcu_gp
		4 root        0 -20       0      0      0 I   0.0  0.0   0:00.00 rcu_par_gp
		6 root        0 -20       0      0      0 I   0.0  0.0   0:00.00 kworker/0:0H-ev
		8 root        0 -20       0      0      0 I   0.0  0.0   0:00.63 kworker/0:1H-ev
		9 root        0 -20       0      0      0 I   0.0  0.0   0:00.00 mm_percpu_wq
		10 root      20   0       0      0      0 S   0.0  0.0   0:00.18 ksoftirqd/0
		11 root      20   0       0      0      0 I   0.0  0.0   0:02.67 rcu_sched
		12 root      rt   0       0      0      0 S   0.0  0.0   0:00.03 migration/0
		14 root      20   0       0      0      0 S   0.0  0.0   0:00.00 cpuhp/0
		15 root      20   0       0      0      0 S   0.0  0.0   0:00.00 cpuhp/1
		16 root      rt   0       0      0      0 S   0.0  0.0   0:00.32 migration/1
		17 root      20   0       0      0      0 S   0.0  0.0   0:00.15 ksoftirqd/1
		19 root       0 -20       0      0      0 I   0.0  0.0   0:00.00 kworker/1:0H-ev
		22 root      20   0       0      0      0 S   0.0  0.0   0:00.00 kdevtmpfs
		23 root       0 -20       0      0      0 I   0.0  0.0   0:00.00 netns
		24 root      20   0       0      0      0 S   0.0  0.0   0:00.01 kauditd
		25 root      20   0       0      0      0 S   0.0  0.0   0:00.00 khungtask

17.ps -ef:
The ps command in Linux is a powerful tool that allows you to view information about the processes running on your Linux system.
Options:

ps -ef or ps -aux ? List currently running processes in full format
ps -ax ? List currently running processes
ps -u username ? List processes for a specific user
ps -C command ? List processes for a given command

OUTPUT:

	[root@sdbt ~]# ps -ef
	UID        PID  PPID  C STIME TTY          TIME CMD
	root         1     0  0 09:31 ?        00:00:05 /usr/lib/systemd/systemd
	--switched-root --system --deserialize 22

	root         2     0  0 09:31 ?        00:00:00 [kthreadd]
	root         3     2  0 09:31 ?        00:00:00 [rcu_gp]
	root         4     2  0 09:31 ?        00:00:00 [rcu_par_gp]
	root         6     2  0 09:31 ?        00:00:00 [kworker/0:0H-ev]
	root         8     2  0 09:31 ?        00:00:00 [kworker/0:1H-kb]
	root         9     2  0 09:31 ?        00:00:00 [mm_percpu_wq]
	root        10     2  0 09:31 ?        00:00:00 [ksoftirqd/0]
	root        11     2  0 09:31 ?        00:00:02 [rcu_sched]
	root        12     2  0 09:31 ?        00:00:00 [migration/0]
	root        14     2  0 09:31 ?        00:00:00 [cpuhp/0]
	root        15     2  0 09:31 ?        00:00:00 [cpuhp/1]
	root        16     2  0 09:31 ?        00:00:00 [migration/1]
	root        17     2  0 09:31 ?        00:00:00 [ksoftirqd/1]
	root        19     2  0 09:31 ?        00:00:00 [kworker/1:0H-ev]
	root        22     2  0 09:31 ?        00:00:00 [kdevtmpfs]
	root        23     2  0 09:31 ?        00:00:00 [netns]
	root        24     2  0 09:31 ?        00:00:00 [kauditd]
	root        25     2  0 09:31 ?        00:00:00 [khungtaskd]
	root        26     2  0 09:31 ?        00:00:00 [oom_reaper]
	root        27     2  0 09:31 ?        00:00:00 [writeback]
	root        28     2  0 09:31 ?        00:00:00 [kcompactd0]
	root        29     2  0 09:31 ?        00:00:00 [ksmd]
	root        84     2  0 09:31 ?        00:00:00 [kintegrityd]
	root        85     2  0 09:31 ?        00:00:00 [kblockd]
	root        86     2  0 09:31 ?        00:00:00 [blkcg_punt_bio]
	root        87     2  0 09:31 ?        00:00:00 [tpm_dev_wq]
	root        88     2  0 09:31 ?        00:00:00 [md]
	root        89     2  0 09:31 ?        00:00:00 [edac-poller]
	root        90     2  0 09:31 ?        00:00:00 [devfreq_wq]
	root        91     2  0 09:31 ?        00:00:00 [watchdogd]
	root        93     2  0 09:31 ?        00:00:05 [kswapd0:0]
	root        95     2  0 09:31 ?        00:00:00 [kthrotld]
	root        96     2  0 09:31 ?        00:00:00 [acpi_thermal_pm]

18. Iostat:
The iostat command is used for monitoring system input/output device loading by observing the time the devices are active in relation to their average
transfer rates.

Options:

iostat -x : Show more details statistics information.
iostat -c : Show only the cpu statistic.
iostat -d : Display only the device report.
iostat -xd : Show extended I/O statistic for device only.

	[root@sdbt test]# iostat
	Linux 5.4.17-2136.318.7.2.el7uek.x86_64 (sdbt.localdomain) 	10/20/2023
	_x86_64_	(2 CPU)

	avg-cpu:  %user   %nice %system %iowait  %steal   %idle
				  0.50    0.08    1.58    3.69    0.00   94.16
	Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
	--------          -----   ----------   ----------  ----------  --------
	sda               9.57       301.44       135.42    5630832    2529592
	scd0              0.00         0.00         0.00         62          0

	[root@sdbt test]#

19.Vmstat:
The vmstat command reports statistics about kernel threads in the run and wait queue, memory, paging, disks, interrupts, system calls,
context switches, and CPU activity.


	[root@sdbt test]# vmstat
	procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu-----
	r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa st
	2  0 267520  47452     20 902952    1    8   151    68  629  588  1  2 94  4  0
	[root@sdbt test]#

20.Cpuinfo:
cpu in Linux is used to get CPU information of the system.

How to ch eck how many CPUs are there in the Linux system

/proc/cpuinfo. ...
nproc command. ...
top or htop command. ...
hwinfo. ...
dmidecode command. ...
getconf _NPROCESSORS_ONLN command.

	[root@sdbt test]# cat /proc/cpuinfo
	processor	: 0
	vendor_id	: GenuineIntel
	cpu family	: 6

	model		: 126
	model name	: Intel(R) Core(TM) i3-1005G1 CPU @ 1.20GHz
	stepping	: 5

	cpu MHz		: 1190.391
	cache size	: 4096 KB
	physical id	: 0
	siblings	: 2

	core id		: 0
	cpu cores	: 2
	apicid		: 0

	initial apicid	: 0
	fpu		: yes
	fpu_exception	: yes
	cpuid level	: 22
	wp		: yes

	flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36
	clflush mmx fxsr sse sse2 ht syscall nx rdtscp lm constant_tsc rep_good nopl xtopology
	nonstop_tsc cpuid tsc_known_freq pni pclmulqdq ssse3 cx16 pcid sse4_1 sse4_2 x2apic
	movbe popcnt aes xsave avx rdrand hypervisor lahf_lm abm 3dnowprefetch invpcid_single
	fsgsbase avx2 invpcid rdseed clflushopt md_clear flush_l1d arch_capabilities
	bugs		: spectre_v1 spectre_v2 spec_store_bypass swapgs itlb_multihit
	srbds mmio_stale_data retbleed

	bogomips	: 2380.78
	clflush size	: 64
	cache_alignment	: 64
	address sizes	: 39 bits physical, 48 bits virtual
	power management:

	processor	: 1
	vendor_id	: GenuineIntel
	cpu family	: 6
	model		: 126

	model name	: Intel(R) Core(TM) i3-1005G1 CPU @ 1.20GHz
	stepping	: 5
	cpu MHz		: 1190.391
	cache size	: 4096 KB
	physical id	: 0
	siblings	: 2
	core id		: 1
	cpu cores	: 2
	apicid		: 1

	initial apicid	: 1
	fpu		: yes
	fpu_exception	: yes
	cpuid level	: 22
	wp		: yes

	flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36
	clflush mmx fxsr sse sse2 ht syscall nx rdtscp lm constant_tsc rep_good nopl xtopology
	nonstop_tsc cpuid tsc_known_freq pni pclmulqdq ssse3 cx16 pcid sse4_1 sse4_2 x2apic
	movbe popcnt aes xsave avx rdrand hypervisor lahf_lm abm 3dnowprefetch invpcid_single
	fsgsbase avx2 invpcid rdseed clflushopt md_clear flush_l1d arch_capabilities.

	bugs		: spectre_v1 spectre_v2 spec_store_bypass swapgs itlb_multihit
	srbds mmio_stale_data retbleed

	bogomips	: 2380.78
	clflush size	: 64
	cache_alignment	: 64
	address sizes	: 39 bits physical, 48 bits virtual
	power management:

	[root@sdbt test]#

21.Meminfo:
The /proc/meminfo file inside the /proc pseudo-filesystem provides a usage report about memory on the system.

	[root@sdbt test]# cat /proc/meminfo
	MemTotal:        1733372 kB
	MemFree:          138520 kB
	MemAvailable:     344832 kB
	Buffers:              20 kB
	Cached:           755712 kB
	SwapCached:         9368 kB
	Active:           991084 kB
	Inactive:         346272 kB
	Active(anon):     848332 kB
	Inactive(anon):   288344 kB
	Active(file):     142752 kB
	Inactive(file):    57928 kB
	Unevictable:       12388 kB
	Mlocked:           12388 kB
	SwapTotal:       4194300 kB
	SwapFree:        3926780 kB
	Dirty:                40 kB
	Writeback:             0 kB
	AnonPages:        588860 kB
	Mapped:           411972 kB
	Shmem:            544528 kB
	KReclaimable:      34576 kB
	Slab:             108608 kB
	SReclaimable:      34576 kB
	SUnreclaim:        74032 kB
	KernelStack:        9280 kB
	PageTables:        83472 kB
	NFS_Unstable:          0 kB
	Bounce:                0 kB
	WritebackTmp:          0 kB
	CommitLimit:     5060984 kB
	Committed_AS:    5818820 kB
	VmallocTotal:   34359738367 kB
	VmallocUsed:       34944 kB
	VmallocChunk:          0 kB
	Percpu:              600 kB
	HardwareCorrupted:     0 kB
	AnonHugePages:         0 kB
	ShmemHugePages:        0 kB
	ShmemPmdMapped:        0 kB
	FileHugePages:         0 kB
	FilePmdMapped:         0 kB
	CmaTotal:              0 kB
	CmaFree:               0 kB
	HugePages_Total:       0
	HugePages_Free:        0
	HugePages_Rsvd:        0
	HugePages_Surp:        0
	Hugepagesize:       2048 kB
	Hugetlb:               0 kB
	DirectMap4k:      145344 kB
	DirectMap2M:     1951744 kB
	[root@sdbt test]#

22.Su:
The su command changes user credentials to those of the root user or to the user specified by the Name parameter, and initiates a new session.

	[root@sdbt test]# su - oracle
	Last login: Fri Oct 20 11:13:17 IST 2023 on pts/1

23.free -G:
The free command in Linux is a commonly used utility that provides information about the system's memory usage, including both physical and virtual memory.

	[root@sdbt ~]# free --g
				total        used        free      shared  buff/cache   available
	Mem:			1		0           0           0           0           0
	Swap:			3		0           3
	[root@sdbt ~]#

24.Uname:
The command ‘uname‘ displays the information about the system.
Options:

$uname -a

$uname -s

$uname -n


	[root@sdbt ~]# uname
	Linux

24.Umask:
Umask (short for user file-creation mode mask) is used by UNIX-based systems to set default permissions for newly created files and directories.

	[root@sdbt ~]# umask
	0022

25.Passwd :
The passwd command changes the login password or password phrase for the user ID specified.

	[oracle@sdbt ~]$ su - root
	Password:
	Last login: Fri Oct 20 15:49:14 IST 2023 on pts/0
	[root@sdbt ~]# passwd oracle
	Changing password for user oracle.
	New password:
	BAD PASSWORD: The password is shorter than 8 characters
	Retype new password:
	passwd: all authentication tokens updated successfully.
	[root@sdbt ~]#

26.Find : Helps you find things, and not just by filename.

26.1:Delete Files Older Than X Minutes

	[root@sdbt tesdb]# ls -lrt
	total 0
	drwxr-xr-x. 2 root root 38 Oct 25 13:43 tesdb1
	-rw-r--r--. 1 root root  0 Oct 25 13:45 tesdbfile
	[root@sdbt tesdb]#
	[root@sdbt tesdb]# find . -name "tes*" -type f -mmin +30 -delete
	[root@sdbt tesdb]# ll
	total 0
	drwxr-xr-x. 2 root root 6 Oct 25 15:28 tesdb1
	[root@sdbt tesdb]#
	First, we’ve specified the starting point for files lookup, it’s
	the current working directory ".".
	Then, we have the file name criteria prefixed with the -name switch.
	The switch -type f means we want to look for files only.
	The -mmin stands for the modification time, and +15 means we want files
	that were last modified 15 minutes ago or earlier.

26.2 Delete Files Older Than X Days :

It only takes a small change to the find command to switch from minutes to days: find . -name "access*.log" -type f -mtime +5 -delete

Here, the -mtime switch says we want to delete files that were modified at least 5 days ago.

26.3 Delete Files Older Than X Days With a Prompt :

We might be concerned that an incorrectly constructed delete command might end updeleting the wrong files.
A small variation of the above command will prompt us before deletion.

Let’s add the -i switch to the rm command:
find . -name "access*log" -exec rm -i {} \;
This way, we can decide which files get deleted.

27.Who:
who command is a tool print information about users who are currently logged in.

	[root@sdbt ~]# who
	root     :0           2023-10-20 09:50 (:0)
	root     pts/0        2023-10-20 09:50 (:0)
	root     pts/1        2023-10-20 11:13 (:0)
	[root@sdbt ~]#

28.Ping:
The ping command in Linux is a utility that helps to test connectivity between two devices on a network.

	[root@sdbt ~]# ping
	Usage: ping [-aAbBdDfhLnOqrRUvV64] [-c count] [-i interval] [-I interface]
			  [-m mark] [-M pmtudisc_option] [-l preload] [-p pattern] [-Q tos]
			  [-s packetsize] [-S sndbuf] [-t ttl] [-T timestamp_option]
			  [-w deadline] [-W timeout] [hop1 ...] destination
	Usage: ping -6 [-aAbBdDfhLnOqrRUvV] [-c count] [-i interval] [-I interface]
			  [-l preload] [-m mark] [-M pmtudisc_option]
			  [-N nodeinfo_option] [-p pattern] [-Q tclass] [-s packetsize]
			  [-S sndbuf] [-t ttl] [-T timestamp_option] [-w deadline]
			  [-W timeout] destination
	[root@sdbt tesdb]# ping google.com
	PING google.com (142.250.195.110) 56(84) bytes of data.
	64 bytes from maa03s39-in-f14.1e100.net (142.250.195.110): icmp_seq=1 ttl=119 time=6.68 ms
	64 bytes from maa03s39-in-f14.1e100.net (142.250.195.110): icmp_seq=2 ttl=119 time=7.07 ms
	64 bytes from maa03s39-in-f14.1e100.net (142.250.195.110): icmp_seq=3 ttl=119 time=7.46 ms
	^C
	--- google.com ping statistics ---
	3 packets transmitted, 3 received, 0% packet loss, time 2002ms
	rtt min/avg/max/mdev = 6.682/7.072/7.460/0.324 ms

29.Awk:
Awk is a scripting language used for manipulating data and generating reports. The awk command programming language requires no compiling
and allows the user to use variables, numeric functions, string functions, and logical operators.

	[root@sdbt tesdb]# cat > employee.txt
	ajay manager account 45000
	sunil clerk account 25000
	varun manager sales 50000
	amit manager account 47000
	tarun peon sales 15000
	deepak clerk sales 23000
	sunil peon sales 13000
	satvik director purchase 80000
	[root@sdbt tesdb]# cat employee.txt
	ajay manager account 45000
	sunil clerk account 25000
	varun manager sales 50000
	amit manager account 47000
	tarun peon sales 15000
	deepak clerk sales 23000
	sunil peon sales 13000
	satvik director purchase 80000

29.1.Default behavior of Awk:
By default Awk prints every line of data from the specified file.

	[root@sdbt tesdb]# awk '{print}' employee.txt
	ajay manager account 45000
	sunil clerk account 25000
	varun manager sales 50000
	amit manager account 47000
	tarun peon sales 15000
	deepak clerk sales 23000
	sunil peon sales 13000
	satvik director purchase 80000
	[root@sdbt tesdb]#

29.2.Print the lines which match the given pattern

	[root@sdbt tesdb]# awk '/manager/ {print}' employee.txt
	ajay manager account 45000
	varun manager sales 50000
	amit manager account 47000

29.3. Splitting a Line Into Fields :
For each record i.e line, the awk command splits the record delimited by whitespace character by default and stores it in the $n variables.
If the line has 4 words, it will be stored in $1, $2, $3 and $4 respectively. Also, $0 represents the whole line.

	[root@sdbt tesdb]# awk '{print $1,$4}' employee.txt
	ajay 45000
	sunil 25000
	varun 50000
	amit 47000
	tarun 15000
	deepak 23000
	sunil 13000
	satvik 80000

29.4 Use of NR built-in variables (Display Line Number)

	[root@sdbt tesdb]# awk '{print NR,$0}' employee.txt

	1 ajay manager account 45000
	2 sunil clerk account 25000
	3 varun manager sales 50000
	4 amit manager account 47000
	5 tarun peon sales 15000
	6 deepak clerk sales 23000
	7 sunil peon sales 13000
	8 satvik director purchase 80000

29.5 Another use of NR built-in variables (Display Line From 3 to 6)

	[root@sdbt tesdb]# awk 'NR==3, NR==6 {print NR,$0}' employee.txt

	3 varun manager sales 50000
	4 amit manager account 47000
	5 tarun peon sales 15000
	6 deepak clerk sales 23000

30.Yum:
Yum is a command-line package manager for RPM-based Linux systems, such as Red Hat Enterprise Linux, CentOS, Fedora, and Oracle Linux.
Options:

	-h, 				--help
					show this help message and exit

	-t, 				--tolerant
					be tolerant of errors

	-C, 				--cacheonly
					run entirely from system cache, don't update cache

	-c [config file], 		--config=[config file]
					config file location

	-R [minutes], 			--randomwait=[minutes]
					maximum command wait time

	-d [debug level], 		--debuglevel=[debug level]
					debugging output level

					--showduplicates
					show duplicates, in repos, in list/search commands

	-e [error level], 		--errorlevel=[error level]
					error output level

					--rpmverbosity=[debug level name]
					debugging output level for rpm

	-q, 				--quiet
					quiet operation

	-v, 				--verbose
					verbose operation

	-y, 				--assumeyes
					answer yes for all questions

					--assumeno
					answer no for all questions

					--version
					show Yum version and exit

					--installroot=[path]
					set install root

					--enablerepo=[repo]
					enable one or more repositories (wildcards allowed)

					--disablerepo=[repo]
					disable one or more repositories (wildcards allowed)

	-x [package], 		--exclude=[package]
					exclude package(s) by name or glob

					--disableexcludes=[repo]
					disable exclude from main, for a repo or for
					everything

					--disableincludes=[repo]
					disable includepkgs for a repo or for everything

					--obsoletes
					enable obsoletes processing during updates

					--noplugins
					disable Yum plugins

					--nogpgcheck
					disable gpg signature checking

					--disableplugin=[plugin]
					disable plugins by name

					--enableplugin=[plugin]
					enable plugins by name

					--skip-broken
					skip packages with depsolving problems

					--color=COLOR
					control whether color is used

					--releasever=RELEASEVER
					set value of $releasever in yum config and repo files

					--downloadonly
					don't update, just download

					--downloaddir=DLDIR
					specifies an alternate directory to store packages

					--setopt=SETOPTS
					set arbitrary config and repo options

					--bugfix
					Include bugfix relevant packages, in updates

					--security
					Include security relevant packages, in updates

					--advisory=ADVS, --advisories=ADVS
					Include packages needed to fix the given
					advisory, in updates

					--bzs=BZS
					Include packages needed to fix the given
					BZ, in updates

					--cves=CVES
					Include packages needed to fix the given
					CVE, in  updates

					--sec-severity=SEVS, --secseverity=SEVS
					Include security relevant packages matching the
					severity, in updates

Plugin Options:
30.1. To Install
a. To install any package on the Linux system, we can fire the yum installand the package name:

	# yum install package1.rpm
	# yum install package1.rpm package2.rpm package3.rpm package4.rpm
	b. Yum utility generally ask for the confirmation for package installation,
	if you want to specify it in the command

	itself then fire below command
	# yum install package1.rpm -y

30.2. To Search

	To search for any package on the RPM repository (it can be RHN,
	Cent OS repository etc.):

	# yum search package1.rpm
	# yum search package1 package2
	# yum search all

30.3. To Update

	To update any existing package on the system fire below update command:
	# yum update package1.rpm
	# yum update package1.rpm package2.rpm
	# yum update package1.rpm -y

30.4. To remove/uninstall
To remove any existing package from the system:

	# yum remove package1.rpm
	# yum remove package1.rpm package2.rpm
	# yum remove package1.rpm -y

30.5. To update the entire system for the available updates from Vendor repository:

	# yum check-update
	# yum update
	# yum update –y
	# yum update yum

30.6. Get info :

		  To get the information about any package:

		  # yum info yum
		  # yum info vsftpd

31. /etc/redhat-release : To display the Red Hat Enterprise Linux version

	[root@sdbt tesdb]# cat /etc/redhat-release
	Red Hat Enterprise Linux Server release 7.9 (Maipo)

32.KILL:
kill command in Linux (located in /bin/kill), is a built-in command which is used to terminate processes manually. kill command sends a signal to a
process that terminates the process. If the user doesn’t specify any signal which is to be sent along with the kill command, then a default TERM signal
is sent that terminates the process.
32.1. kill -l

	To display all the available signals, you can use the below command option:
	[root@sdbt tesdb]# kill -l
	1) SIGHUP	 2) SIGINT	 3) SIGQUIT	 4) SIGILL	 5) SIGTRAP
	6) SIGABRT	 7) SIGBUS	 8) SIGFPE	 9) SIGKILL	10) SIGUSR1
	11) SIGSEGV	12) SIGUSR2	13) SIGPIPE	14) SIGALRM	15) SIGTERM
	16) SIGSTKFLT	17) SIGCHLD	18) SIGCONT	19) SIGSTOP	20) SIGTSTP
	21) SIGTTIN	22) SIGTTOU	23) SIGURG	24) SIGXCPU	25) SIGXFSZ
	26) SIGVTALRM	27) SIGPROF	28) SIGWINCH	29) SIGIO	30) SIGPWR
	31) SIGSYS	34) SIGRTMIN	35) SIGRTMIN+1	36) SIGRTMIN+2	37) SIGRTMIN+3
	38) SIGRTMIN+4	39) SIGRTMIN+5	40) SIGRTMIN+6	41) SIGRTMIN+7	42) SIGRTMIN+8
	43) SIGRTMIN+9	44) SIGRTMIN+10	45) SIGRTMIN+11	46) SIGRTMIN+12	47) SIGRTMIN+13
	48) SIGRTMIN+14	49) SIGRTMIN+15	50) SIGRTMAX-14	51) SIGRTMAX-13	52) SIGRTMAX-12
	53) SIGRTMAX-11	54) SIGRTMAX-10	55) SIGRTMAX-9	56) SIGRTMAX-8	57) SIGRTMAX-7
	58) SIGRTMAX-6	59) SIGRTMAX-5	60) SIGRTMAX-4	61) SIGRTMAX-3	62) SIGRTMAX-2
	63) SIGRTMAX-1	64) SIGRTMAX

32.2 kill PID

	This option specifies the process ID of the process to be killed.
	root@sdbt ~]# ps
	PID TTY          TIME CMD
	24370 pts/0    00:00:00 bash
	24473 pts/0    00:00:00 ps
	[root@sdbt ~]# kill 24473
	bash: kill: (24473) - No such process

32.3. Signals can be specified in three ways:
Signals can be specified in three ways; they are as follows:
1) By number:
We can specify a signal using a number. For example, we have a PID `1212` and want to send a `SIGKILL` signal to kill this PID. SIGKILL
has a signal number of `9` (To find signal numbers run `kill -l` command).
Syntax:

[root@sdbt ~]# ps
	  PID TTY          TIME CMD
	24370 pts/0    00:00:00 bash
	25568 pts/0    00:00:00 ps
	[root@sdbt ~]# kill -9 25568

2) With SIG prefix (e.g/ -SIGkill)
We can also specify signal using SIG prefix. For example, we need to send a signal `SIGTERM` and PID is `1432`.
To just check signal number of `SIGTERM`signal we can use `kill -l` command.
Syntax:

	
	kill -SIGTERM 25568

33. nohup and & DISPLAY:
A command in Linux systems that keep processes running even after exiting the shell or terminal

	[root@sdbt ~]# nohup df -h
	nohup: ignoring input and appending output to ‘nohup.out’
	You have new mail in /var/spool/mail/root
	[root@sdbt ~]# cat nohup.out
	Filesystem      Size  Used Avail Use% Mounted on
	devtmpfs        829M     0  829M   0% /dev
	tmpfs           847M   24K  847M   1% /dev/shm
	tmpfs           847M  9.4M  837M   2% /run
	tmpfs           847M     0  847M   0% /sys/fs/cgroup
	/dev/sda2        56G   33G   24G  59% /
	newshared       441G  154G  287G  35% /media/sf_newshared
	tmpfs           170M   32K  170M   1% /run/user/0
	/dev/sr0         59M   59M     0 100% /run/media/root/VBox_GAs_6.1.34
	[root@sdbt ~]# nohup date
	nohup: ignoring input and appending output to ‘nohup.out’
	[root@sdbt ~]# cat nohup.out
	Filesystem      Size  Used Avail Use% Mounted on
	devtmpfs        829M     0  829M   0% /dev
	tmpfs           847M   24K  847M   1% /dev/shm
	tmpfs           847M  9.4M  837M   2% /run
	tmpfs           847M     0  847M   0% /sys/fs/cgroup
	/dev/sda2        56G   33G   24G  59% /
	newshared       441G  154G  287G  35% /media/sf_newshared
	tmpfs           170M   32K  170M   1% /run/user/0
	/dev/sr0         59M   59M     0 100% /run/media/root/VBox_GAs_6.1.34
	Wed Oct 25 16:47:07 IST 2023

34.sysctl.conf:
In Linux, sysctl.conf is a configuration file used to control various kernel parameters and settings. It allows you to configure and tune the behavior of the
Linux kernel to suit your specific needs. This file is typically located in the /etc/sysctl.conf or /etc/sysctl.d/ directory.

View Current Kernel Parameters:
You can view the current kernel parameters and their values using the sysctl command. For example, to view the net.ipv4.ip_forward parameter,
you can use the following command:

	[root@sdbt ~]# sysctl net.ipv4.ip_forward
	net.ipv4.ip_forward = 0
	[root@sdbt ~]#

Edit sysctl.conf:
To configure kernel parameters persistently, you can edit the sysctl.conf file. You will typically need root privileges to edit this file.
You can use a text editor like nano or vi to open the file:

	Vi  /etc/sysctl.conf

Set Kernel Parameters: Inside the sysctl.conf file, you can set various parameters using the following format:

	parameter_name = value

	For example, to enable IP forwarding, you can add the following line to the file:
	net.ipv4.ip_forward = 1

Reload Configuration:
After editing the sysctl.conf file, you need to reload the configuration to apply the changes without rebooting the system.
You can do this using the following command:


	sysctl -p

35.ORATAB:
The oratab file in Linux is a configuration file specific to Oracle Database installations. It is used to manage the automatic startup and
shutdown of Oracle database instances on a given system.
The oratab file is typically located in the /etc directory, and its full path is usually /etc/oratab.

Here's how the oratab file works:
Listing Oracle Instances: The oratab file contains a list of Oracle database instances installed on the system. Each line in the file represents one instance
and has the following format:

	[oracle@sdbt ~]$ cat /etc/oratab

#
# This file is used by ORACLE utilities. It is created by root.sh
# and updated by either Database Configuration Assistant while creating
# a database or ASM Configuration Assistant while creating ASM instance.

# A colon, ':', is used as the field terminator. A new line terminates
# the entry. Lines beginning with a pound sign, '#', are comments.
#

# Entries are of the form: # $ORACLE_SID:$ORACLE_HOME::
#
# The first and second fields are the system identifier and home
# directory of the database respectively. The third field indicates
# to the dbstart utility that the database should , "Y", or should not,
# "N", be brought up at system boot time.
#
# Multiple entries with the same $ORACLE_SID are not allowed.
#
#
dev:/u01/app/oracle/product/12.2.0/dbhome_1:N
orcl:/u01/app/oracle/product/12.2.0/dbhome_1:N

Editing the oratab File:
If you install or remove Oracle instances, you may need to manually edit the oratab file to add or remove entries for those instances.
Be sure to follow the specified format when making changes.
It's essential to use caution when editing the oratab file, as incorrect entries can lead to issues with Oracle instance management.
Changes to the file should be made by individuals with appropriate privileges and knowledge of Oracle Database administration.

36: chkconfig:
chkconfig is a command in Linux used to manage and view the services and daemons that are configured to start automatically at boot time.
It is typically used on systems that use the SysV init system or Systemd.

Here are some common chkconfig commands and their usage:
36.1. List All Services :

	To list all services and their current runlevel settings
	[root@sdbt ~]# chkconfig --list

Note: This output shows SysV services only and does not include native systemd services. SysV configuration data might be overridden by
native systemd configuration.
If you want to list systemd services use 'systemctl list-unit-files'. To see services enabled on particular target use

	
	'systemctl list-dependencies [target]'.

	netconsole     	0:off	1:off	2:off	3:off	4:off	5:off	6:off
	network        	0:off	1:off	2:on	3:on	4:on	5:on	6:off
	rhnsd          	0:off	1:off	2:on	3:on	4:on	5:on	6:off

36.2. Check the Status of a Specific Service:

	Check the Status of a Specific Service:
	You can check the status of a specific service for a particular
	runlevel using the following syntax:

	chkconfig --list 
	Replace  with the name of the service you want to check.

36.3.Enable a Service:

	To enable a service to start automatically at boot time, you can
	use the --level option.
	For example,
	to enable the Apache web server (httpd) to start at runlevels 3 and 5, use:

	chkconfig --level 35 httpd on

37.mount :
In Linux, the mount command is used to attach (mount) a file system to a specific directory in the file system hierarchy. This process allows you to access
the files and data on the mounted file system as if they were part of your local file system. Mounting is a fundamental operation in Linux and is used to work
with various types of storage devices, network file systems, and more.the basic syntax of the mount command:
mount [options] source destination

source:
This is the device or file containing the file system you want to mount. It can be a device name (e.g., a hard drive partition such as /dev/sdb1),
a network location (e.g., an NFS or SMB share), or a disk image file.

destination:
This is the directory where you want to mount the file system. It must be an empty directory, and its contents will be hidden while the file system is mounted.
Common options used with the mount command include -t to specify the file system type (e.g., ext4, NFS, or SMB), and various options for specific file systems.

Mount a USB Drive:
To mount a USB drive located at /dev/sdb1 to a directory such as /mnt/usb, you can use the following command:
mount /dev/sdb1 /mnt/usb

Mount a Network Share (NFS):
To mount a network share from an NFS server, you would use a command like this:
mount -t nfs server:/share /mnt/nfs

Mount an ISO Image:
We can also mount an ISO image file directly to a directory. For example:
mount -o loop /path/to/your.iso /mnt/iso
The mount command has many options and is highly versatile. It is an essential tool for managing file systems and storage devices in Linux.
Be cautious when using the mount command, as incorrect usage can lead to data loss or other issues. Always ensure that the destination directory is
empty and take care when specifying options for different file system types.

38.Unmount a File System:
In Linux, the umount command is used to unmount (or detach) a currently mounted file system, making it no longer accessible through the
specified mount point. Properly unmounting file systems is important to ensure data integrity and prevent potential data corruption.
Here is the basic syntax of the umount command:


	umount [options] target

target:
This is the directory where the file system is mounted. When you use umount, you specify the path to the mount point, not the device or file.
Common options used with the umount command include -l (lazy unmount, allowing the file system to be unmounted when it is no longer in use)
and -f (force unmount, even if the file system is busy).

Unmount a Mounted Directory:
To unmount a directory, such as /mnt/usb, you would use the following command:


	umount /mnt/usb

Lazy Unmount:
If the file system is in use (e.g., files are open), you can use the -l option for a lazy unmount. This allows the file system to be unmounted when
it's no longer in use:


	umount -l /mnt/usb

Force Unmount:
In some cases, you may need to forcibly unmount a busy file system. Use the -f option, but be cautious as this can lead to data corruption:
umount -f /mnt/usb
Remember that it's essential to unmount file systems properly to avoid data corruption. For network file systems, unmounting might involve additional steps,
such as disconnecting from the network share or using specific commands for that file system type. Always ensure that you're not actively using the files
within the file system before unmounting.

39.mkfs.ext3:
The mkfs.ext3 command in Linux is used to create an Ext3 file system on a block device or a partition. Ext3 is a widely used file system in Linux, known for its
journaling capabilities, which help improve data integrity and recovery in the event of unexpected system crashes.
Here is the basic syntax for creating an Ext3 file system using mkfs.ext3:
mkfs.ext3 [options] device

device:
This is the block device or partition where you want to create the Ext3 file system. You should specify the path to the device, such as /dev/sdX1,
where "X" represents the drive letter and "1" is the partition number.

Common options for mkfs.ext3 include specifying the block size (-b), the inode size (-I), and others. However, many of these options can be left to
their default values, and the file system will be created with reasonable defaults.

Here's an example of creating an Ext3 file system on a partition:


	mkfs.ext3 /dev/sdX1

(Replace /dev/sdX1 with the actual device or partition you want to format as Ext3.)
After running the mkfs.ext3 command, the file system on the specified device or partition will be created, and you can then mount it to a directory to start
using it.
Please note that mkfs.ext3 is part of the e2fsprogs package, which is usually pre-installed on most Linux distributions. Always use caution
when formatting a device or partition, as it will erase all data on that storage medium. Double-check that you are formatting the correct device to avoid data loss.

40.how to add new disk for OEL (linux)
ADD NEW DISK(fdisk -l,mount, mkfs.ext3
fdisk also known as format disk is a dialog-driven command in Linux used for creating and manipulating disk partition table.
It is used for the view, create, delete, change, resize, copy and move partitions on a hard drive using the dialog-driven interface.
fdisk allows you to create a maximum of four primary partitions and the number of logical partition depends on the size of the hard disk you are using.

It allows the user:

To Create space for new partitions.
Organizing space for new drives.
Re-organizing old drives.
Copying or Moving data to new disks(partitions).

Command Purpose
fdisk -m Print the available (FDISK) commands
fdisk -p Print the partition table
0
======================================================
fdisk -d Delete a partition

=======================================================
fdisk -l to view details of available disk partitions.

=======================================================
Create a Hard Disk Partition:
For this go inside the hard drive partition that is the /dev/sdb partition, and use the following command: fdisk /dev/sdb
fdisk -w Write the table to the hard drive

Now you have to type n to create new partition and then type p for making a primary partition and e for making an
extended or logical partition depending on the type of partition to make.

View Partition on a Specific Disk:
Below command is used to view all disk partitions on device /dev/sda. fdisk -s /dev/sda to view the partition size.

41.RPM:
In Linux, the rpm command is used to manage Red Hat Package Manager (RPM) packages. The rpm command has various options
and subcommands for performing different package-related operations. The rpm -uvh command is used to upgrade or install an
RPM package with some specific options:
Query all installed packages:

	rpm -qa
	[root@sdbt ~]# rpm -qa|grep oracle
	oraclelinux-release-7.9-1.0.9.el7.x86_64
	oraclelinux-release-el7-1.0-17.el7.x86_64
	oracle-logos-70.7.0-1.0.7.el7.noarch
	oracle-database-server-12cR2-preinstall-1.0-5.el7.x86_64
	[root@sdbt ~]#

OPTIONS IN rpm:

	-i | --install:
		This option is used to install a new package

	rpm -i sample_package.rpm

	-q | --query:
	This option is used to query an installed package
	or a .rpm package file.

	rpm -q sample_package

	-e | --erase:
	This option is used to remove an installed package.
	rpm -e sample_package

Advanced Use Cases of rpm Command in Linux
Upgrade a package:

	rpm -U sample_package.rpm

	Verify an installed package:
	rpm -V sample_package

-u : This option stands for "upgrade." It allows you to upgrade an existing package if it's already installed or install it if it's not already installed.
-v : This option stands for "verbose." It provides more detailed information about the installation or upgrade process, showing the progress.
-h : This option stands for "hash." It displays a progress bar during the installation or upgrade to give you an indication of how far along the process is.
Here's how you can use the rpm -uvh command:


	rpm -uvh package.rpm

Replace package.rpm with the actual name of the RPM package you want to upgrade or install.
For example, if you have a package named "example.rpm," you can use the following command to upgrade or install it:


	rpm -uvh example.rpm

This command will upgrade the package if it's already installed, or it will install it if it's not already on your system, all while providing a verbose output
and a progress bar.

42.DF - disk free space:

	df  

	* The df command displays information about total space and available space on a
	file system. The FileSystem parameter specifies the name of the device on which
	the file system resides, the directory on which the file system is mounted, or
	the relative path name of a file system. 


	Display disk space usage for all mounted filesystems:

	df

	Options	                     Objective

	-h or --human-readable	      Displays sizes in a human-readable format (e.g.,
	"1.5G" for 1.5 gigabytes)


	Display disk space usage in human-readable format:

	[root@sdbt ~]# df -h 

	Filesystem      Size  Used Avail Use% Mounted on
	devtmpfs        829M     0  829M   0% /dev
	tmpfs           847M   24K  847M   1% /dev/shm
	tmpfs           847M  9.4M  837M   2% /run
	tmpfs           847M     0  847M   0% /sys/fs/cgroup
	/dev/sda2        56G   34G   23G  60% /
	newshared       441G  154G  287G  35% /media/sf_newshared
	tmpfs           170M   28K  170M   1% /run/user/0
	/dev/sr0         59M   59M     0 100% /run/media/root/VBox_GAs_6.1.34

43.DU - DISK USAGE:

The du (disk usage) command measures the disk space occupied by files or directories.

What is the du *| sort command? du -skh
The du command in Linux is used to estimate the space used by files and directories. The options you provided, du -skh, have the following meanings:

du : The disk usage command.

-s : This option stands for "summarize." It causes du to display only the total usage for each argument (i.e., the total usage of the specified file or
directory and its subdirectories) , rather than a detailed breakdown of every subdirectory.

-k : This option stands for "kilobytes." It displays the sizes in kilobytes, which is a common unit for disk space measurement.

-h : This option stands for "human-readable." It makes the output more human-friendly by using larger units (e.g., K for kilobytes, M for megabytes)
when the sizes are too large. This option is useful for making the output easier to read.

[root@sdbt ~]# du -skh tesdb

0K tesdb

44. SAR:
What is sar command linux monitor system performance?
The "sar" command in Linux is a powerful system performance monitoring tool that stands for "System Activity Reporter." It collects, reports, and
analyzes various system activity and performance metrics, providing administrators with valuable insights into the health and efficiency of a Linux system.
The "sar" command is part of the "sysstat" package, which is a set of utilities for collecting and reporting system performance data

CPU Usage Details :
To report CPU details a total of 5 times with the interval of 2 seconds. If the interval command is set to zero, average statistics from the time system
started are presented. If the count is not provided and the interval is given, statistics are provided continuously after every interval.

sar -u (cpu):

	[root@sdbt ~]# sar -u

	Linux 5.4.17-2136.318.7.2.el7uek.x86_64 (sdbt.localdomain) 	10/26/2023
	_x86_64_	(2 CPU)


	09:22:32 AM       LINUX RESTART

	09:30:01 AM     CPU     %user     %nice   %system   %iowait    %steal     %idle
	09:40:03 AM     all      0.89      1.32      1.47      4.19      0.00     92.13
	09:50:02 AM     all      0.46      0.22      0.80      2.37      0.00     96.15
	10:00:01 AM     all      0.09      0.00      0.43      0.03      0.00     99.46
	10:10:01 AM     all      0.08      0.00      0.41      0.01      0.00     99.50
	10:20:01 AM     all      0.07      0.00      0.40      0.05      0.00     99.48
	10:30:01 AM     all      0.06      0.00      0.32      0.01      0.00     99.61
	10:40:01 AM     all      0.70      0.00      0.70      0.76      0.00     97.84
	10:50:01 AM     all      1.13      0.00      0.99      0.02      0.00     97.87
	11:00:01 AM     all      0.83      0.00      0.80      0.16      0.00     98.21
	11:10:01 AM     all      1.27      0.00      1.14      0.35      0.00     97.25
	11:20:01 AM     all      0.89      0.00      0.83      0.39      0.00     97.89
	11:30:01 AM     all      0.48      0.00      0.61      0.02      0.00     98.88
	11:40:04 AM     all      1.32      0.00      2.25     15.89      0.00     80.54
	Average:        all      0.63      0.12      0.86      1.85      0.00     96.55

	11:55:49 AM       LINUX RESTART

	12:01:41 PM       LINUX RESTART

	12:10:05 PM     CPU     %user     %nice   %system   %iowait    %steal     %idle
	12:20:03 PM     all      1.09      0.00      1.78      4.71      0.00     92.42
	12:30:01 PM     all      1.10      0.00      1.77      1.30      0.00     95.83
	12:40:01 PM     all      0.57      0.00      1.45      1.12      0.00     96.86
	12:50:01 PM     all      0.84      0.00      1.66      1.27      0.00     96.22
	01:00:01 PM     all      0.98      0.00      1.70      1.41      0.00     95.92
	01:10:02 PM     all      0.86      0.00      1.57      1.37      0.00     96.20
	01:20:01 PM     all      0.16      0.00      1.22      0.84      0.00     97.77
	01:30:01 PM     all      0.12      0.00      1.30      0.62      0.00     97.96
	01:40:02 PM     all      0.20      0.01      1.57     10.83      0.00     87.39
	01:50:01 PM     all      0.31      0.00      1.48      2.49      0.00     95.72
	02:00:03 PM     all      0.75      0.00      2.05      4.93      0.00     92.27
	02:10:01 PM     all      0.55      0.00      1.87      2.49      0.00     95.08
	02:20:01 PM     all      0.32      0.00      1.75      1.21      0.00     96.73
	02:30:02 PM     all      0.17      0.00      1.70      1.06      0.00     97.06
	02:40:01 PM     all      0.28      0.00      1.70      1.07      0.00     96.95
	02:50:01 PM     all      0.17      0.00      1.72      0.85      0.00     97.25
	03:00:01 PM     all      0.16      0.00      1.72      2.48      0.00     95.64
	03:10:01 PM     all      0.20      0.00      2.03      0.81      0.00     96.95
	03:20:01 PM     all      0.19      0.00      2.01      0.64      0.00     97.16
	03:30:01 PM     all      0.18      0.00      2.00      0.41      0.00     97.41
	03:40:01 PM     all      0.29      0.00      1.99      0.53      0.00     97.19
	04:30:01 PM     all      0.20      0.00      1.82      2.44      0.00     95.53
	Average:        all      0.45      0.00      1.72      2.03      0.00     95.80

sar -q (load average)

	Run Queue Length and Load Average
	To report run queue length, number of processes and load average
	[root@sdbt ~]# sar -q
	Linux 5.4.17-2136.318.7.2.el7uek.x86_64 (sdbt.localdomain) 10/26/2023 _x86_64_ (2 CPU)

	09:22:32 AM       LINUX RESTART

	09:30:01 AM   runq-sz  plist-sz   ldavg-1   ldavg-5  ldavg-15   blocked
	09:40:03 AM         1       508      0.50      0.50      0.45         0
	09:50:02 AM         1       506      0.03      0.14      0.27         0
	10:00:01 AM         0       504      0.00      0.02      0.14         0
	10:10:01 AM         0       504      0.00      0.00      0.06         1
	10:20:01 AM         0       505      0.00      0.00      0.02         0
	10:30:01 AM         0       505      0.00      0.02      0.00         0
	10:40:01 AM         3       512      0.03      0.06      0.01         0
	10:50:01 AM         0       510      0.01      0.04      0.02         0
	11:00:01 AM         1       512      0.08      0.06      0.01         0
	11:10:01 AM         0       512      0.09      0.08      0.02         0
	11:20:01 AM         0       511      0.01      0.04      0.01         0
	11:30:01 AM         0       511      0.00      0.02      0.00         0
	11:40:04 AM         0       573      0.21      0.84      0.54         0
	Average:            0       513      0.07      0.14      0.12         0
	11:55:49 AM       LINUX RESTART
	12:01:41 PM       LINUX RESTART
	12:10:05 PM   runq-sz  plist-sz   ldavg-1   ldavg-5  ldavg-15   blocked
	12:20:03 PM         0       573      0.29      0.41      0.52         0
	12:30:01 PM         0       575      0.09      0.13      0.31         3
	12:40:01 PM         0       570      0.16      0.08      0.18         1
	12:50:01 PM         0       568      0.14      0.11      0.15         1
	01:00:01 PM         0       568      0.22      0.14      0.13         0
	01:10:02 PM         1       568      0.04      0.17      0.15         0
	01:20:01 PM         1       571      0.02      0.04      0.08         1
	01:30:01 PM         3       575      0.08      0.06      0.08         0
	01:40:02 PM         0       571      0.33      0.62      0.36         0
	01:50:01 PM         1       570      0.32      0.24      0.26         0
	02:00:03 PM         0       568      0.03      0.13      0.20         0
	02:10:01 PM         0       568      0.37      0.25      0.20         0
	02:20:01 PM         1       570      0.04      0.11      0.14         0
	02:30:02 PM         0       574      0.04      0.07      0.09         0
	02:40:01 PM         0       570      0.03      0.05      0.07         1
	02:50:01 PM         0       568      0.15      0.13      0.09         0
	03:00:01 PM         0       569      0.16      0.16      0.12         0
	03:10:01 PM         0       570      0.04      0.04      0.06         0
	03:20:01 PM         0       571      0.07      0.06      0.06         0
	03:30:01 PM         1       574      0.11      0.04      0.03         0
	03:40:01 PM         0       573      0.09      0.05      0.01         1
	04:30:01 PM         0       575      0.15      0.10      0.03         0
	Average:            0       571      0.14      0.14      0.15         0

sar -S (Swap)

	Swapping Statistics
	To report statistics about swapping

sar -q

	Linux 5.4.17-2136.318.7.2.el7uek.x86_64 (sdbt.localdomain) 	10/26/2023
	_x86_64_	(2 CPU)
	09:22:32 AM       LINUX RESTART
	09:30:01 AM   runq-sz  plist-sz   ldavg-1   ldavg-5  ldavg-15   blocked
	09:40:03 AM         1       508      0.50      0.50      0.45         0
	09:50:02 AM         1       506      0.03      0.14      0.27         0
	10:00:01 AM         0       504      0.00      0.02      0.14         0
	10:10:01 AM         0       504      0.00      0.00      0.06         1
	10:20:01 AM         0       505      0.00      0.00      0.02         0
	10:30:01 AM         0       505      0.00      0.02      0.00         0
	10:40:01 AM         3       512      0.03      0.06      0.01         0
	10:50:01 AM         0       510      0.01      0.04      0.02         0
	11:00:01 AM         1       512      0.08      0.06      0.01         0
	11:10:01 AM         0       512      0.09      0.08      0.02         0
	11:20:01 AM         0       511      0.01      0.04      0.01         0
	11:30:01 AM         0       511      0.00      0.02      0.00         0
	11:40:04 AM         0       573      0.21      0.84      0.54         0
	Average:            0       513      0.07      0.14      0.12         0

sar -r Unused Memory

	
	sar -r (Memory Usage Details)

To report about the amount of memory used, amount of memory free, available cache, available buffers total 3 times with the interval of 1 second.

	[root@sdbt ~]# sar -r
	Linux 5.4.17-2136.318.7.2.el7uek.x86_64 (sdbt.localdomain) 	10/26/2023
	_x86_64_	(2 CPU)

	09:22:32 AM       LINUX RESTART

   09:30:01 AM kbmemfree kbmemused  %memused kbbuffers kbcached  kbcommit   %commit  kbactive  kbinact kbdirty
   09:40:03 AM    27508   1705864     98.41       32    814188   4475828     75.51    900284   587192    4528
   09:50:02 AM   257372   1476000     85.15       20    788104   4265952     71.97    445112   827508       4
   10:00:01 AM   257064   1476308     85.17       20    788720   4269780     72.03    444916   827968       4
   10:10:01 AM   256472   1476900     85.20       20    788936   4265352     71.96    445260   827956       4
   10:20:01 AM   250076   1483296     85.57       20    794496   4265980     71.97    445840   833480       8
   10:30:01 AM   249272   1484100     85.62       20    795244   4266584     71.98    446524   833384      28
   10:40:01 AM   208000   1525372     88.00       20    820784   4306848     72.66    471348   845616      28
   10:50:01 AM   207204   1526168     88.05       20    821212   4305216     72.63    471588   845952      24
   11:00:01 AM    60760   1672612     96.49       20    966908   4311808     72.74    495680   968148      36
   11:10:01 AM    46148   1687224     97.34       20    949004   4337740     73.18    552040   925632      40
   11:20:01 AM    81692   1651680     95.29       20    912512   4339880     73.21    594300   848088     284
   11:30:01 AM   153660   1579712     91.14       20    832328   4344324     73.29    581208   789308      40
   11:40:04 AM    13952   1719420     99.20       20    902984   5800056     97.85    976784   495092      64
   Average:      159168   1574204     90.82       21    844263   4427334     74.69    559299   804256     392

sar -B - kernel paging (Paging Statistics)
To report paging statistics (KBs paged-in/sec, KBs paged-out/sec, pagefault/sec etc.)

	[root@sdbt ~]# sar -B
	Linux 5.4.17-2136.318.7.2.el7uek.x86_64 (sdbt.localdomain)
	10/26/2023 	_x86_64_	(2 CPU)

	09:22:32 AM       LINUX RESTART

	09:30:01 AM  pgpgin/s pgpgout/s   fault/s  majflt/s  pgfree/s pgscank/s pgscand/s pgsteal/s    %vmeff
	09:40:03 AM    988.99    637.71   1973.99      0.98   1557.13      0.00      0.00    250.93      0.00
	09:50:02 AM   1709.14     22.95    806.17      0.70   1130.43      0.00      0.00    425.93      0.00
	10:00:01 AM      0.88      1.90    360.40      0.01    251.87      0.00      0.00      0.00      0.00
	10:10:01 AM      0.43      2.15    362.49      0.01    253.87      0.00      0.00      0.00      0.00
	10:20:01 AM      9.15      2.00    399.15      0.06    278.37      0.00      0.00      0.00      0.00
	10:30:01 AM      1.11      1.74    398.36      0.00    278.74      0.00      0.00      0.00      0.00
	10:40:01 AM     42.68      5.88    492.41      0.19    349.90      0.00      0.00      0.00      0.00
	10:50:01 AM      0.37      2.30    473.96      0.01    354.90      0.00      0.00      0.00      0.00
	11:00:01 AM      0.81    264.98    519.02      0.00    353.56      0.00      0.00      0.00      0.00
	11:10:01 AM      2.95    844.28    552.75      0.01    548.56      0.00      0.00     98.89      0.00
	11:20:01 AM      0.35    685.42    543.21      0.04    509.89      0.00      0.00     92.53      0.00
	11:30:01 AM      0.12     52.95    501.05      0.00    400.87      0.00      0.00      0.00      0.00
	11:40:04 AM   4992.36    564.49   2169.40      4.96   2259.73      0.00      0.00   1618.12      0.00
	Average:       597.33    237.89    735.49      0.54    656.60      0.00      0.00    191.68      0.00

Sar -dp:

	[root@sdbt ~]# sar -dp
	Linux 5.4.17-2136.318.7.2.el7uek.x86_64 (sdbt.localdomain)
	10/26/2023 	_x86_64_	(2 CPU)

	09:22:32 AM       LINUX RESTART

	09:30:01 AM       DEV       tps  rd_sec/s  wr_sec/s  avgrq-sz  avgqu-sz     await     svctm     %util
	09:40:03 AM       sda     32.44   1977.92   1275.41    100.29      0.27      8.20      3.51     11.37
	09:40:03 AM       sr0      0.01      0.06      0.00      4.00      0.00     33.11     33.89      0.05
	09:50:02 AM       sda     10.06   3418.28     45.90    344.40      0.24     24.35      6.94      6.99
	09:50:02 AM       sr0      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00
	10:00:01 AM       sda      0.37      1.76      3.81     15.10      0.00     12.98      5.22      0.19
	10:00:01 AM       sr0      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00
	10:10:01 AM       sda      0.42      0.77      4.30     12.12      0.01     21.18      6.14      0.26
	10:10:01 AM       sr0      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00
	10:20:01 AM       sda      0.53     18.40      3.97     42.35      0.02     28.75      8.60      0.45
	10:20:01 AM       sr0      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00
	10:30:01 AM       sda      0.33      2.21      3.52     17.11      0.01     39.11     10.22      0.34
	10:30:01 AM       sr0      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00

	10:30:01 AM       DEV       tps  rd_sec/s  wr_sec/s  avgrq-sz  avgqu-sz     await     svctm     %util
	10:40:01 AM       sda      2.64     85.36     11.76     36.81      0.05     18.26     11.42      3.01
	10:40:01 AM       sr0      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00
	10:50:01 AM       sda      0.36      0.73      4.61     14.97      0.00     11.22      4.67      0.17
	10:50:01 AM       sr0      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00
	11:00:01 AM       sda      0.95      1.61    529.96    560.57      0.01     14.64      5.72      0.54
	11:00:01 AM       sr0      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00
	11:10:01 AM       sda      2.12      5.90   1688.56    800.21      0.04     20.72      5.21      1.10
	11:10:01 AM       sr0      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00
	11:20:01 AM       sda      1.62      0.71   1370.83    847.12      0.04     26.17      5.43      0.88
	11:20:01 AM       sr0      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00
	11:30:01 AM       sda      0.54      0.23    105.91    195.36      0.01     15.58      4.55      0.25
	11:30:01 AM       sr0      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00

	11:30:01 AM       DEV       tps  rd_sec/s  wr_sec/s  avgrq-sz  avgqu-sz     await     svctm     %util
	11:40:04 AM       sda     52.91   9984.73   1128.98    210.07      3.45     65.22      4.78     25.27
	11:40:04 AM       sr0      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00
	Average:          sda      8.12   1194.65    475.77    205.80      0.32     39.58      4.83      3.92
	Average:          sr0      0.00      0.00      0.00      4.00      0.00     33.11     33.89      0.00

sar -b (aveerage disk io)

	[root@sdbt ~]# sar -b
	Linux 5.4.17-2136.318.7.2.el7uek.x86_64 (sdbt.localdomain)
	10/26/2023 	_x86_64_	(2 CPU)

	09:22:32 AM       LINUX RESTART

	09:30:01 AM       tps      rtps      wtps   bread/s   bwrtn/s
	09:40:03 AM     32.45     29.32      3.13   1977.98   1275.41
	09:50:02 AM     10.06      9.11      0.94   3418.28     45.90
	10:00:01 AM      0.37      0.03      0.34      1.76      3.81
	10:10:01 AM      0.42      0.04      0.38      0.77      4.30
	10:20:01 AM      0.53      0.17      0.35     18.40      3.97
	10:30:01 AM      0.33      0.04      0.30      2.21      3.52
	10:40:01 AM      2.64      1.79      0.85     85.36     11.76
	10:50:01 AM      0.36      0.02      0.34      0.73      4.61
	11:00:01 AM      0.95      0.06      0.89      1.61    529.96
	11:10:01 AM      2.12      0.14      1.97      5.90   1688.56
	11:20:01 AM      1.62      0.04      1.57      0.71   1370.83
	11:30:01 AM      0.54      0.02      0.53      0.23    105.91
	11:40:04 AM     52.91     43.12      9.79   9984.73   1128.98
	Average:         8.12      6.47      1.65   1194.65    475.77

sar -n (network):

	-n { keyword [,...] | ALL }
			  Report network statistics.

	Possible keywords are DEV, EDEV, NFS, NFSD, SOCK, IP,
	EIP, ICMP, EICMP,TCP, ETCP, UDP, SOCK6, IP6,  EIP6,
	ICMP6,  EICMP6  and UDP6.

45.CRONTAB:

The crontab is a list of commands that you want to run on a regular schedule, and also the name of the command used to manage that list.
Crontab stands for "cron table, " because it uses the job scheduler cron to execute tasks; cron itself is named after "chronos, " the Greek word
for time.cron is the system process which will automatically perform tasks for you according to a set schedule.
The schedule is called the crontab, which is also the name of the program used to edit that schedule.

Linux Crontab Format
MIN HOUR DOM MON DOW CMD

	Field    Description    Allowed Value
	MIN      Minute field    0 to 59
	HOUR     Hour field      0 to 23
	DOM      Day of Month    1-31
	MON      Month field     1-12
	DOW      Day Of Week     0-6
	CMD      Command         Any command to be executed.

To find the list of jobs created:

	[root@sdbt ~]# crontab -l
	no crontab for root
	[root@sdbt ~]#

To create new job:

	[root@sdbt ~]# crontab -e
	no crontab for root - using an empty one
	crontab: installing new crontab

	*/1 * * * * touch testfilecreation
	~
	~
	~

	~

	 -- INSERT --
	[root@sdbt ~]# ls -lrt
	total 2936
	drwxrwxr-x. 6 root root        4096 Sep  4  2021 pgbadger-11.6
	-rw-------. 1 root root        2222 Mar  1  2022 anaconda-ks.cfg
	-rw-r--r--. 1 root root        2253 Mar  1  2022 initial-setup-ks.cfg
	drwxr-xr-x. 2 root root           6 Mar  1  2022 Templates
	drwxr-xr-x. 2 root root           6 Mar  1  2022 Downloads
	drwxr-xr-x. 2 root root           6 Mar  1  2022 Desktop
	drwxr-xr-x. 2 root root           6 Mar  1  2022 Videos
	drwxr-xr-x. 2 root root           6 Mar  1  2022 Public
	drwxr-xr-x. 2 root root           6 Mar  1  2022 Music
	drwxr-xr-x. 2 root root           6 Mar  1  2022 Documents
	drwxr-xr-x. 5 root root          39 Apr 10  2023 perl5
	-rw-r--r--. 1 root root     2974369 Aug 31 15:09 v11.6.tar.gz
	drwxr-xr-x. 4 root root          53 Sep 21 12:20 sdbt
	dr-xr-xr-x. 2 root root          46 Sep 22 12:10 filecomm
	drwxr-xr-x. 3 root root          34 Oct 20 14:44 test
	-rw-r--r--. 1 root oinstall       0 Oct 25 12:18 test_file
	drwxr-xr-x. 3 root root        4096 Oct 25 12:18 Pictures
	drwxr-xr-x. 3 root root          40 Oct 25 15:42 tesdb
	-rw-------. 1 root root         482 Oct 25 16:47 nohup.out

LIST JOBS:

	[root@sdbt ~]# crontab -l
	*/1 * * * * touch testfilecreation

	 FILE CREATED:
	[root@sdbt ~]# ls -lrt
	total 2936
	drwxrwxr-x. 6 root root        4096 Sep  4  2021 pgbadger-11.6
	-rw-------. 1 root root        2222 Mar  1  2022 anaconda-ks.cfg
	-rw-r--r--. 1 root root        2253 Mar  1  2022 initial-setup-ks.cfg
	drwxr-xr-x. 2 root root           6 Mar  1  2022 Templates
	drwxr-xr-x. 2 root root           6 Mar  1  2022 Downloads
	drwxr-xr-x. 2 root root           6 Mar  1  2022 Desktop
	drwxr-xr-x. 2 root root           6 Mar  1  2022 Videos
	drwxr-xr-x. 2 root root           6 Mar  1  2022 Public
	drwxr-xr-x. 2 root root           6 Mar  1  2022 Music
	drwxr-xr-x. 2 root root           6 Mar  1  2022 Documents
	drwxr-xr-x. 5 root root          39 Apr 10  2023 perl5
	-rw-r--r--. 1 root root     2974369 Aug 31 15:09 v11.6.tar.gz
	drwxr-xr-x. 4 root root          53 Sep 21 12:20 sdbt
	dr-xr-xr-x. 2 root root          46 Sep 22 12:10 filecomm
	drwxr-xr-x. 3 root root          34 Oct 20 14:44 test
	-rw-r--r--. 1 root oinstall       0 Oct 25 12:18 test_file
	drwxr-xr-x. 3 root root        4096 Oct 25 12:18 Pictures
	drwxr-xr-x. 3 root root          40 Oct 25 15:42 tesdb
	-rw-------. 1 root root         482 Oct 25 16:47 nohup.out
	-rw-r--r--. 1 root root           0 Oct 26 17:04 testfilecreation
	[root@sdbt ~]#

	 TO REMOVE CRON TAB:
	[root@sdbt ~]# crontab -r
	[root@sdbt ~]# crontab -l
	no crontab for root

46. SCP

scp stands for Secure Copy Protocol, and it is a command-line tool in Linux and Unix-like operating systems that allows you to securely transfer
files and directories between a local and a remote system. scp uses the SSH (Secure Shell) protocol for authentication and encryption,
making it a secure way to transfer files over a network.

	[oracle@tesdb1 ~]$ vi sample
	[oracle@tesdb1 ~]$ ll
	total 12
	-rw-r--r--. 1 oracle oinstall 221 Oct 20 01:19 db.env
	drwxr-xr-x. 2 oracle oinstall   6 Oct 19 00:59 Desktop
	drwxr-xr-x. 2 oracle oinstall   6 Oct 19 00:59 Documents
	drwxr-xr-x. 2 oracle oinstall   6 Oct 19 00:59 Downloads
	-rw-r--r--. 1 oracle oinstall 226 Oct 20 01:24 grid.env
	drwxr-xr-x. 2 oracle oinstall   6 Oct 19 00:59 Music
	drwxr-xr-x. 2 oracle oinstall   6 Oct 19 00:59 Pictures
	drwxr-xr-x. 2 oracle oinstall   6 Oct 19 00:59 Public
	-rw-r--r--. 1 oracle oinstall  14 Oct 26 07:53 sample
	drwxr-xr-x. 2 oracle oinstall   6 Oct 19 00:59 Templates
	drwxr-xr-x. 2 oracle oinstall   6 Oct 19 00:59 Videos

	[oracle@tesdb1 ~]$ scp sample root@192.168.1.101:/root
	The authenticity of host '192.168.1.101 (192.168.1.101)' can't be established.
	ECDSA key fingerprint is SHA256:9VHVB8UFkC7vGeeqa48NWPjwfXpA0YVHD6LFGXZBlAE.
	ECDSA key fingerprint is MD5:d8:bd:02:94:74:1a:b0:17:e9:d0:ea:27:4b:ce:46:e5.
	Are you sure you want to continue connecting (yes/no)? yes
	Warning: Permanently added '192.168.1.101' (ECDSA) to the list of known hosts.
	root@192.168.1.101's password:
	sample                                        100%   14     5.4KB/s   00:00

47. SCP
SH, or Secure Shell, is a cryptographic network protocol that provides a secure way to access and manage remote systems.
It is commonly used on Linux and other Unix-like operating systems for secure remote access, file transfers, and remote command execution.
Here are some key aspects of using SSH in Linux:

	[oracle@tesdb1 ~]$ ssh root@192.168.1.101
	root@192.168.1.101's password:
	Last login: Thu Oct 26 13:42:59 2023

	[root@sdbt ~]# logname
	Root

	[root@sdbt ~]# ll
	total 2940
	-rw-------. 1 root root        2222 Mar  1  2022 anaconda-ks.cfg
	drwxr-xr-x. 2 root root           6 Mar  1  2022 Desktop
	drwxr-xr-x. 2 root root           6 Mar  1  2022 Documents
	drwxr-xr-x. 2 root root           6 Mar  1  2022 Downloads
	-rwxr-xr-x. 1 root root          32 Oct 12 15:39 f1
	dr-xr-xr-x. 2 root root          46 Sep 22 12:10 filecomm
	-rw-r--r--. 1 root root        2253 Mar  1  2022 initial-setup-ks.cfg
	drwxr-xr-x. 3 root root          46 Oct 10 16:08 kri
	drwxr-xr-x. 2 root root        4096 Sep 13 12:38 krishna
	drwxr-xr-x. 2 root root           6 Mar  1  2022 Music
	-rw-------. 1 root root         482 Oct 25 16:47 nohup.out
	drwxr-xr-x. 5 root root          39 Apr 10  2023 perl5
	drwxrwxr-x. 6 root root        4096 Sep  4  2021 pgbadger-11.6
	drwxr-xr-x. 3 root root        4096 Oct 25 12:18 Pictures
	drwxr-xr-x. 2 root root           6 Mar  1  2022 Public
	-rw-r--r--. 1 root root          14 Oct 26 17:24 sample
	drwxr-xr-x. 4 root root          53 Sep 21 12:20 sdbt
	drwxr-xr-x. 2 root root           6 Mar  1  2022 Templates
	drwxr-xr-x. 3 root root          40 Oct 25 15:42 tesdb
	drwxr-xr-x. 3 root root          34 Oct 20 14:44 test
	-rw-r--r--. 1 root oinstall       0 Oct 25 12:18 test_file
	-rw-r--r--. 1 root root           0 Oct 26 17:16 testfilecreation
	-rw-r--r--. 1 root root     2974369 Aug 31 15:09 v11.6.tar.gz
	drwxr-xr-x. 2 root root           6 Mar  1  2022 Videos

	[root@sdbt ~]# ls -lrt|grep sample
	-rw-r--r--. 1 root root          14 Oct 26 17:24 sample

	[root@sdbt ~]# hostname -i
	192.168.1.101

	[root@sdbt ~]# exit
	logout
	Connection to 192.168.1.101 closed.

	[oracle@tesdb1 ~]$ hostname -i
	192.168.1.121

	[oracle@tesdb1 ~]$ cat sample
	sample work

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