Essential Linux commands for network engineers

Wed, 20 Dec 2023 00:00:00 +0000

ls:

Lists directories and files in the current directory.
Example:

ubuntu@panda:~$ ls
clab docker-compose downloads hugo package-lock.json scripts
compose docker-vol service lasthop powerlevel10k tf

pwd:

Prints the current working directory.
Example:

ubuntu@panda:~$ pwd
/home/ubuntu

cd:

Navigate through directories.
Example:

ubuntu@panda:~$ cd clab
ubuntu@panda:~/clab$ cd
ubuntu@panda:~$

mkdir:

Create directories.
Example:

ubuntu@panda:~$ mkdir newdir
ubuntu@panda:~$ ls
clab docker-compose downloads hugo newdir powerlevel10k tf
compose docker-vol service lasthop package-lock.json scripts

mv:

Move or rename files.
Example:

ubuntu@panda:~$ mv downloads downloads_backup
ubuntu@panda:~$ ls
clab docker-compose downloads_backup hugo package-lock.json scripts
compose docker-vol service lasthop powerlevel10k tf

cp:

Copy files.
Example:

ubuntu@panda:~$ cp package-lock.json package-lock-backup.json
ubuntu@panda:~$ ls
clab docker-compose downloads hugo package-lock-backup.json package-lock.json powerlevel10k scripts
compose docker-vol service lasthop tf

rm:

Delete files or directories.
Example:

ubuntu@panda:~$ rm package-lock-backup.json
ubuntu@panda:~$ ls
clab docker-compose downloads hugo package-lock.json powerlevel10k scripts
compose docker-vol service lasthop tf

touch:

Create blank/empty files.
Example:

ubuntu@panda:~$ touch newfile.txt
ubuntu@panda:~$ ls
clab docker-compose downloads hugo newfile.txt package-lock.json powerlevel10k scripts
compose docker-vol service lasthop tf

cat:

Display file contents on the terminal.
Example:

ubuntu@panda:~$ cat newfile.txt
hello world

clear:

Clear the terminal display.
Example:

ubuntu@panda:~$ clear

echo:

Print any text that follows the command.
Example:

ubuntu@panda:~$ echo "hello world"
hello world

less:

Display paged outputs in the terminal.
Example:

ubuntu@panda:~$ less package-lock.json

man:

Access manual pages for Linux commands.
Example:

ubuntu@panda:~$ man ls

uname:

Get basic information about the OS.
Example:

ubuntu@panda:~$ uname -a
Linux panda 5.15.0-1049-oracle

whoami:

Get the active username.
Example:

ubuntu@panda:~$ whoami
ubuntu

tar:

Extract and compress files.
Example:

ubuntu@panda:~$ tar -xvf archive.tar

grep:

Search for a string within an output.
Example:

ubuntu@panda:~$ grep "pattern" filename

head:

Return the specified number of lines from the top.
Example:

ubuntu@panda:~$ head -n 5 filename

tail:

Return the specified number of lines from the bottom.
Example:

ubuntu@panda:~$ tail -n 5 filename

diff:

Find the difference between two files.
Example:

ubuntu@panda:~$ diff file1 file2

cmp:

Check if two files are identical.
Example:

ubuntu@panda:~$ cmp file1 file2

comm:

Combine the functionality of diff and cmp.
Example:

ubuntu@panda:~$ comm file1 file2

sort:

Sort the content of a file while outputting.
Example:

ubuntu@panda:~$ sort filename

export:

Export environment variables.
Example:

ubuntu@panda:

ps:

Display active processes.
Example:

ubuntu@panda:~$ ps
PID TTY TIME CMD
1234 pts/1 00:00:01 bash
5678 pts/1 00:00:03 python

kill and killall:

Kill active processes by process ID or name.
Example:

ubuntu@panda:~$ kill 1234
ubuntu@panda:~$ killall python

df:

Display disk filesystem information.
Example:

ubuntu@panda:~$ df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda1 20G 15G 4.0G 80% /

chmod:

Change file permissions.
Example:

ubuntu@panda:~$ chmod 755 script.sh
ubuntu@panda:~$ ls -l script.sh
-rwxr-xr-x 1 ubuntu ubuntu 0 Jan 1 12:00 script.sh

chown:

Grant ownership of files or folders.
Example:

ubuntu@panda:~$ chown ubuntu:ubuntu script.sh
ubuntu@panda:~$ ls -l script.sh
-rwxr-xr-x 1 ubuntu ubuntu 0 Jan 1 12:00 script.sh

ifconfig:

Display network interfaces and IP addresses.
Example:

ubuntu@panda:~$ ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.1.2 netmask 255.255.255.0 broadcast 192.168.1.255

traceroute:

Trace all the network hops to reach the destination.
Example:

ubuntu@panda:~$ traceroute google.com

wget:

Direct download files from the internet.
Example:

ubuntu@panda:~$ wget https://example.com/file.zip

cal:

View a command-line calendar.
Example:

ubuntu@panda:~$ cal
January 2023
Su Mo Tu We Th Fr Sa
1
2 3 4 5 6 7 8
9 10 11 12 13 14 15
16 17 18 19 20 21 22
23 24 25 26 27 28 29
30 31

alias:

Create custom shortcuts for regularly used commands.
Example:

ubuntu@panda:~$ alias ll='ls -l'
ubuntu@panda:~$ ll
total 4
drwxrwxr-x 2 ubuntu ubuntu 4096 Jan 1 12:00 clab

whereis:

Locate the binary, source, and manual pages for a command.
Example:

ubuntu@panda:~$ whereis ls
ls: /bin/ls /usr/share/man/man1/ls.1.gz

whatis:

Find what a command is used for.
Example:

ubuntu@panda:~$ whatis ls
ls (1) - list directory contents

top:

View active processes live with their system usage.
Example:

ubuntu@panda:~$ top

useradd and usermod:

Add new user or change existing users’ data.
Example:

ubuntu@panda:~$ sudo useradd newuser
ubuntu@panda:~$ sudo usermod -aG sudo newuser

passwd:

Create or update passwords for existing users.
Example:

ubuntu@panda:~$ sudo passwd newuser
Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully

ls -1 | wc -l:

Get the count of the files present in a directory.
Example:

ubuntu@panda:~$ ls -1 | wc -l
12

kill:

Command to kill a process (PID).
Example:

ubuntu@panda:~$ kill 1234

w:

Check how many users are logged into Linux.
Example:

ubuntu@panda:~$ w
12:00:00 up 10 days, 2:00, 2 users, load average: 0.00, 0.01, 0.05

date:

Used to check the current date and time in Linux.
Example:

ubuntu@panda:~$ date
Sat Jan 1 12:00:00 UTC 2023

ls -a:

List the hidden files in a directory.
Example:

ubuntu@panda:~$ ls -a
. .. .hiddenfile clab downloads

ls -l:

Check the permissions on all the files.
Example:

ubuntu@panda:~$ ls -l
total 4
drwxrwxr-x 2 ubuntu ubuntu 4096 Jan 1 12:00 clab

ls -R:

List information about files and directories within the file system.
Example:

ubuntu@panda:~$ ls -R
.:
clab downloads
./clab:
file1 file2
./downloads:
file3 file4

rm -rf:

Remove directory with the files.
Example:

ubuntu@panda:~$ rm -rf testdir
ubuntu@panda:~$ ls
clab downloads

About me

Sun, 06 Mar 2022 00:00:00 +0000

Search

Mon, 01 Jan 0001 00:00:00 +0000

Useful links