Linux Basic Commands - Part 1
Linux
Linux is an opensource operating system.The kernel of this operating system is written by Linus Torvalds.
Basic Commands:
pwd:
This command returns the present working directory as output.
Syntax:- pwd
Example:
[user1@node1~] $pwd
/users/home/user1
ls :
This command lists the files and directories under the present working directory.
Syntax: ls -[options]
Example:
[user1@node1~]$ls
bin dev tmp usr
It can be used with multiple options:
l - lists in longname
a - lists all files including hidden files
R - lists all subdirectories recursively.
r - lists files in reverse chronological order
t - lists latest files by modification time
h- lists all files and directories in human-readable format
<command> --help
This gives a brief documentation of the command.
Example:- $ls --help
grep
This command is used to search pattern in file
Syntax: grep -[option] pattern file_path
Example:
[user1@node1~]$ grep passed /root/tmp/certificate.pdf
has passed the examination of
It can be used with multiple options:
-i: Ignores the case
-v: Excludes the pattern found
-E: Extended grep - Regular expressions can be used with patterns
whoami
This command outputs the username of current user logged in
Example:
[user1@node1~]$whoami
user1