Linux basic commands
Updated: Oct 3, 2021
Document Id: RHEL002
In my previous post, I've shown how to install Red Hat Enterprise Linux, in this post I'll explain some basic commands every Linux administrator should know to operate Linux operating system.
Previous post: How to Install RedHat Enterprise Linux 8.2
hostname command, to check server hostname
[root@RHEL82 html]# hostname
RHEL82.localdomain
whoami command, to check login user
[root@RHEL82 html]# whoami
root
uname –a command, to get system identification, mainly kernel version
[root@RHEL82 html]# uname -a
Linux RHEL82.localdomain 4.18.0-193.el8.x86_64 #1 SMP Fri Mar 27 14:35:58 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
To get installed Red Hat Linux version details
[root@RHEL82 html]# cat /etc/redhat-release
Red Hat Enterprise Linux release 8.2 (Ootpa)
ifconfig command, to check server network interface details
[root@RHEL82 html]# ifconfig
ping command, to check connectivity to the server
[root@RHEL82 ~]# ping 192.168.10.10
PING 192.168.10.10 (192.168.10.10) 56(84) bytes of data.
64 bytes from 192.168.10.10: icmp_seq=1 ttl=128 time=20.8 ms
pwd command
Present working directory, when we first login to terminal we are in user home directory, pwd command shows absolute path of the current directory
[root@RHEL82 ~]# pwd
mkdir command
To create an empty directory
[root@RHEL82 ~]# mkdir newfolder
Output: It will create a directory with name newfolder in the current working directory
To create a directory in the specified location
[root@RHEL82 ~]# mkdir /tmp/newfolder
Output: It will create a directory with name newfolder in the /tmp directory
ls command
List of files and directory
[root@RHEL82 ~]# ls
Output: anaconda-ks.cfginitial-setup-ks.cfgnewfolder
To check list of files and directory in the specified location
[root@RHEL82 ~]# ls /tmp/
To check hidden files and folders
[root@RHEL82 ~]# ls –a
To check all files and folder with associated permission
[root@RHEL82 ~]# ls –la
cd command
Change directory- we use this command to change the working directory location.
Example:
[root@RHEL82 ~]# pwd
/root
[root@RHEL82 ~]# ls
anaconda-ks.cfg initial-setup-ks.cfg newfolder
[root@RHEL82 ~]# cd newfolder/
[root@RHEL82 newfolder]# pwd
/root/newfolder
cd.. (double dot) to go parent directory
Example:
[root@RHEL82 html]# pwd
/var/www/html
[root@RHEL82 html]# cd ..
[root@RHEL82 www]# pwd
/var/www
cd (only cd or cd~) to go home directory from anywhere
Example:
[root@RHEL82 ~]# cd /var/www/html/
[root@RHEL82 html]# pwd
/var/www/html
[root@RHEL82 html]# cd
[root@RHEL82 ~]# pwd
/root
cd – (hyphen) to come back previous working directory
Example:
[root@RHEL82 html]# pwd
/var/www/html
[root@RHEL82 html]# cd
[root@RHEL82 ~]# pwd
/root
[root@RHEL82 ~]# cd -
/var/www/html
[root@RHEL82 html]# pwd
/var/www/html