Introduction to LINUX (Basic Commands)
[root@localhost ~]# hostname
localhost.localdomain
[root@localhost ~]# ifconfig
eth0 Link encap:Ethernet HWaddr 00:0C:29:63:46:BD
inet addr:172.16.28.145 Bcast:172.16.28.255 Mask:255.255.255.0
inet6 addr: fe80::20c:29ff:fe63:46bd/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:2332 errors:0 dropped:0 overruns:0 frame:0
TX packets:1455 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:257468 (251.4 KiB) TX bytes:192203 (187.6 KiB)
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:16 errors:0 dropped:0 overruns:0 frame:0
TX packets:16 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:960 (960.0 b) TX bytes:960 (960.0 b)
[root@localhost ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:63:46:bd brd ff:ff:ff:ff:ff:ff
inet 172.16.28.145/24 brd 172.16.28.255 scope global eth0
inet6 fe80::20c:29ff:fe63:46bd/64 scope link
valid_lft forever preferred_lft forever
3: pan0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN
link/ether 42:be:5a:58:ad:92 brd ff:ff:ff:ff:ff:ff
[root@localhost ~]# arp
Address HWtype HWaddress Flags Mask Iface
172.16.28.254 ether 00:50:56:ff:aa:b1 C eth0
172.16.28.2 ether 00:50:56:e6:ec:2b C eth0
172.16.28.1 ether 00:50:56:c0:00:08 C eth0
[root@localhost ~]# logname
root
[root@localhost ~]# who
root tty1 2016-03-26 20:30 (:0)
root pts/0 2016-03-26 20:31 (:0.0)
root pts/1 2016-03-26 20:32 (172.16.28.1)
[root@localhost ~]# who am i
root pts/1 2016-03-26 20:32 (172.16.28.1)
[root@localhost ~]# whoami
root
[root@localhost ~]# id
uid=0(root) gid=0(root) groups=0(root) context=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023
[root@localhost ~]# useradd jack
[root@localhost ~]# passwd jack
Changing password for user jack.
New password:
BAD PASSWORD: it is too short
BAD PASSWORD: is too simple
Retype new password:
passwd: all authentication tokens updated successfully.
mohammedrafi@NOC-RAFI:~$ ssh jack@172.16.28.145
jack@172.16.28.145’s password:
[jack@localhost ~]$ whoami
jack
[jack@localhost ~]$ who
root tty1 2016-03-26 20:30 (:0)
root pts/0 2016-03-26 20:31 (:0.0)
root pts/1 2016-03-26 20:32 (172.16.28.1)
jack pts/2 2016-03-26 21:29 (172.16.28.1)
[jack@localhost ~]$ id
uid=501(jack) gid=501(jack) groups=501(jack) context=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023
[jack@localhost ~]$ tty
/dev/pts/2
[root@localhost ~]# w
21:31:45 up 1:04, 4 users, load average: 0.01, 0.02, 0.05
USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT
root tty1 :0 20:30 1:04m 4.31s 4.31s /usr/bin/Xorg :0 -br -verbose -audit 4 -auth /var/run/gdm/auth-for-gdm-O1LNMm/d
root pts/0 :0.0 20:31 59:53 0.02s 0.02s /bin/bash
root pts/1 172.16.28.1 20:32 0.00s 0.32s 0.19s w
jack pts/2 172.16.28.1 21:29 1:40 0.04s 0.04s -bash
[root@localhost ~]# users
jack root root root
[root@localhost ~]# groups
root
[root@localhost ~]# tty
/dev/pts/1
[root@localhost ~]# pwd
/root
[root@localhost ~]# mkdir first
[root@localhost ~]# cd first/
[root@localhost first]# mkdir second
[root@localhost first]# cd second/
[root@localhost second]# pwd
/root/first/second
[root@localhost second]# cd ..
[root@localhost ~]# runlevel
N 5
[root@localhost first]# pwd
/root/first
[root@localhost first]# cd ..
[root@localhost ~]# pwd
/root
[root@localhost ~]# cd first/second/
[root@localhost second]# pwd
/root/first/second
[root@localhost second]# cd
[root@localhost ~]# pwd
/root
[root@localhost ~]# cd first/second/
[root@localhost second]# pwd
/root/first/second
[root@localhost second]# cd ../..
[root@localhost ~]# pwd
/root
[root@localhost ~]# mkdir one/two/three
mkdir: cannot create directory `one/two/three’: No such file or directory
[root@localhost ~]# mkdir -p one/two/three
[root@localhost ~]# cd one/two/three/
[root@localhost three]# pwd
/root/one/two/three
[root@localhost three]# cd
[root@localhost ~]# pwd
/root
[root@localhost ~]# ls
anaconda-ks.cfg Documents first install.log.syslog one Public Templates
Desktop Downloads install.log Music Pictures rhel-server-6.7-x86_64-dvd.iso Videos
[root@localhost ~]# ls -a
. .bashrc Documents .gnome2 .gvfs Music .pulse-cookie
.. .cache Downloads .gnome2_private .ICEauthority .nautilus rhel-server-6.7-x86_64-dvd.iso
anaconda-ks.cfg .config .esd_auth .gnote install.log one .ssh
.bash_history .cshrc first .gnupg install.log.syslog Pictures .tcshrc
.bash_logout .dbus .gconf .gstreamer-0.10 .local Public Templates
.bash_profile Desktop .gconfd .gtk-bookmarks .mozilla .pulse Videos
[root@localhost ~]# ls -l
total 3752044
-rw——-. 1 root root 3301 Dec 24 00:59 anaconda-ks.cfg
drwxr-xr-x. 2 root root 4096 Dec 23 19:34 Desktop
drwxr-xr-x. 2 root root 4096 Dec 23 19:34 Documents
drwxr-xr-x. 2 root root 4096 Dec 23 19:34 Downloads
drwxr-xr-x. 3 root root 4096 Mar 26 21:34 first
-rw-r–r–. 1 root root 42780 Dec 24 00:59 install.log
-rw-r–r–. 1 root root 9380 Dec 24 00:56 install.log.syslog
drwxr-xr-x. 2 root root 4096 Dec 23 19:34 Music
drwxr-xr-x. 3 root root 4096 Mar 26 21:36 one
drwxr-xr-x. 2 root root 4096 Dec 23 19:34 Pictures
drwxr-xr-x. 2 root root 4096 Dec 23 19:34 Public
-rwxr-xr-x. 1 root root 3841982464 Feb 22 05:22 rhel-server-6.7-x86_64-dvd.iso
drwxr-xr-x. 2 root root 4096 Dec 23 19:34 Templates
drwxr-xr-x. 2 root root 4096 Dec 23 19:34 Videos
[root@localhost ~]# uname -a
Linux localhost.localdomain 2.6.32-573.el6.x86_64 #1 SMP Wed Jul 1 18:23:37 EDT 2015 x86_64 x86_64 x86_64 GNU/Linux
[root@localhost ~]# getconf LONG_BIT
64
kernal-name
[root@localhost ~]# uname -s
Linux
hostname
[root@localhost ~]# uname -n
localhost.localdomain
kernal-release
[root@localhost ~]# uname -r
2.6.32-573.el6.x86_64
Machine-hardware name
[root@localhost ~]# uname -m
x86_64
kernal process type
[root@localhost ~]# uname -p
x86_64
Hard-ware platform
[root@localhost ~]# uname -i
x86_64
operating-system
[root@localhost ~]# uname -o
GNU/Linux
[root@localhost ~]# cat /etc/system-release
Red Hat Enterprise Linux Server release 6.7 (Santiago)
[root@localhost ~]# alias x=hostname
[root@localhost ~]# x
localhost.localdomain
[root@localhost ~]# arch
x86_64
[root@localhost ~]# alias -p
alias cp=’cp -i’
alias l.=’ls -d .* –color=auto’
alias ll=’ls -l –color=auto’
alias ls=’ls –color=auto’
alias mv=’mv -i’
alias rm=’rm -i’
alias which=’alias | /usr/bin/which –tty-only –read-alias –show-dot –show-tilde’
alias x=’hostname’
[root@localhost ~]# unalias x
[root@localhost ~]# x
-bash: x: command not found
[root@localhost ~]# ls
anaconda-ks.cfg Documents first install.log.syslog one Public Templates
Desktop Downloads install.log Music Pictures rhel-server-6.7-x86_64-dvd.iso Videos
[root@localhost ~]# stat one/
File: `one/’
Size: 4096 Blocks: 8 IO Block: 4096 directory
Device: 803h/2051d Inode: 524591 Links: 3
Access: (0755/drwxr-xr-x) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2016-03-26 21:36:33.823343770 -0700
Modify: 2016-03-26 21:36:13.334344400 -0700
Change: 2016-03-26 21:36:13.334344400 -0700
[root@localhost ~]# stat anaconda-ks.cfg
File: `anaconda-ks.cfg’
Size: 3301 Blocks: 8 IO Block: 4096 regular file
Device: 803h/2051d Inode: 131081 Links: 1
Access: (0600/-rw——-) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2015-12-23 19:38:42.073296687 -0800
Modify: 2015-12-24 00:59:23.445998907 -0800
Change: 2015-12-24 00:59:43.342998933 -0800
[root@localhost ~]# history
[root@localhost ~]# touch file1
[root@localhost ~]# cat >file1
hai this is first file
[root@localhost ~]# cat file1
hai this is first file
[root@localhost ~]# cat >> file1
this is newly appended
[root@localhost ~]# cat file1
hai this is first file
this is newly appended
[root@localhost ~]# cat > file1
it will replace all what is exixting
[root@localhost ~]# cat file1
it will replace all what is exixting
[root@localhost ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda3 55G 6.2G 46G 12% /
tmpfs 358M 76K 358M 1% /dev/shm
/dev/sda1 283M 41M 228M 16% /boot
[root@localhost ~]# df -hT
Filesystem Type Size Used Avail Use% Mounted on
/dev/sda3 ext4 55G 6.2G 46G 12% /
tmpfs tmpfs 358M 76K 358M 1% /dev/shm
/dev/sda1 ext4 283M 41M 228M 16% /boot
[root@localhost ~]# du /root/one/
4 /root/one/two/three
8 /root/one/two
12 /root/one/
[root@localhost ~]# du -h /root/one/
4.0K /root/one/two/three
8.0K /root/one/two
12K /root/one/
[root@localhost ~]# free
total used free shared buffers cached
Mem: 732388 581172 151216 3380 35732 222480
-/+ buffers/cache: 322960 409428
Swap: 4095996 1932 4094064
[root@localhost ~]# free -m
total used free shared buffers cached
Mem: 715 567 147 3 34 217
-/+ buffers/cache: 315 399
Swap: 3999 1 3998
[root@localhost ~]# swapon -s
Filename Type Size Used Priority
/dev/sda2 partition 4095996 1932 -1
[root@localhost ~]# swapoff -a
[root@localhost ~]# swapon -s
Filename Type Size Used Priority
[root@localhost ~]# swapon -a
[root@localhost ~]# swapon -s
Filename Type Size Used Priority
/dev/sda2 partition 4095996 0 -1
[root@localhost ~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 60G 0 disk
├─sda1 8:1 0 300M 0 part /boot
├─sda2 8:2 0 3.9G 0 part [SWAP]
└─sda3 8:3 0 55.8G 0 part /
sr0 11:0 1 1024M 0 rom
[root@localhost ~]# blkid /dev/sda1
/dev/sda1: UUID=”d5b88247-f67f-4b40-9862-16826e250b78″ TYPE=”ext4″
[root@localhost ~]# blkid /dev/sda2
/dev/sda2: UUID=”af69d0e5-b600-49a0-9228-d4195936bdd2″ TYPE=”swap”
[root@localhost ~]# blkid /dev/sda3
/dev/sda3: UUID=”cbc3eda3-9a23-4943-a8c4-3990addeb161″ TYPE=”ext4″
linuxmadeeasy 