Day3: Leaning mostly used Linux Commands in DevOps

4 min readJan 25, 2023

This is the Day 3. I hope you have read all my previous blogs on DevOps. In an earlier blog, we discussed DevOps and Linux basics structure and commands. Today will learn about Linux commands which are mostly used in DevOps.

Root Permission

sudo -This command executes with superuser privileges.
sudo -i :- This command will switch to root user
sudo su :- This command will activate the root permission to the user.

2. Commands about users

whoami :- This command is to check which user is logged in.
id :- This command will show the details about the user
who :- This command will show which user is logged in with some detail
w :- This command will show all logged-in user details.

3. System information

uname :- This command will show the kernel name
uname -r :- show the Karnal version
uname -a :- show the kernel details
hostname :- This is the command to show the hostname of the server
date :- This is the command to show the date and time zone of the server

4. Network Information

ip a :- This command will show all network adapters that are connected to the virtual machine.
nmtui :- It is a text-based user interface that allows users to manage network connections.
ping :- It is used to test the reachability of a host on the network.

5. History

history :- It shows their previously executed commands
history 10 :- It will display the last 10 commands
!number :- It will display of executed command from history by its number

Example of !numbers
!42   # execute command number 45 from the command history
!-6   # execute command number 3 before the current command
!ls   # execute the most recent command that starts with 'ls'

6. File and Directory

touch :- create a file
mkdir :- create directory
rm :- remove file
rmdir :- remove directory
rm -r :- remove the directory recursively

7. Cat

cat :- Thi command is used to display the content of the text file.
cat -b :- This is used to add line numbers to non-blank lines
cat -n :- This is used to add line numbers to all lines.
cat -s :- This is used to squeeze lines into one line

8. Grep

grep :- It returns results for the matching string option.
grep -i :- It returns the case-sensitive strings
grep -n :- It prints the matching string along with their line numbers
grep -v :- It returns the lines not matching the search string
grep -c :- It returns the number of lines in which the results matched search string

9. User and Groups

which :- This command is used to know the location of the command.
useradd :- Add user in server
userdel :- Delete user from the server

There are some commands which contain user and group information. /etc/passwd, /etc/group and /etc/shadow
useradd, usermod, userdel, and passed commands used to manage users.
groupadd and groupdel commands are used to manage groups.
change command used to configure and view the password expiration settings for the user.

10. File System Permission