100 linux useful commands

Introduction

We are going to see 100 linux useful commands, that may be handy in case of any trouble shooting or user/admin related activities

ls – List the contents of a directory

# ls

cd – Change the current directory

# cd Documents

mkdir – Create a new directory

mkdir my_directory

mv – Move or rename a file or directory

# mv old_file.txt new_file.txt

cp – Copy a file or directory# cp file1.txt file2.txt

cp file1.txt file2.txt

rm – Remove a file or directory

rm file.txt

chmod – Change the permissions of a file or directory

chmod 755 file.txt

grep – Search for a string in a file

grep "string" file.txt

find – Search for files in a directory

find . -name "*.txt"

cat – Display the contents of a file

cat file.txt

head – Display the first few lines of a file

head -n 5 file.txt

tail – Display the last few lines of a file

tail -n 5 file.txt

sort – Sort the contents of a file

sort file.txt

uniq – Remove duplicate lines from a file

uniq file.txt

tar – Create an archive file

tar -cvf archive.tar file1.txt file2.txt

gzip – Compress a file

gzip file.txt

gunzip – Decompress a file

gunzip file.txt.gz

ssh – Connect to a remote computer

ssh user@host

scp – Copy files between computers

scp file.txt user@host:~/

ping – Test the connection to a remote computer

ping www.example.com

ifconfig – Display network configuration

ifconfig

route – Display the routing table

route -n

netstat – Display network connections

netstat -an

top – Display the top running processes

top

ps – Display the running processes

ps -ef

kill – Terminate a process

kill -9 1234

df – Display disk usage

df -h

du – Display disk usage of a directory

du -sh /home/user

free – Display memory usage

free -m

wget – Download a file from the internet

wget http://example.com/file.zip

curl – Download a file from the internet

curl -O http://example.com/file.zip

apt-get – Install a package

apt-get install package

yum – Install a package

yum install package

systemctl – Manage system services

systemctl start service

service – Manage system services

service service start

reboot – Reboot the system

reboot

shutdown – Shutdown the system

shutdown -h now

date – Display the current date and time

date

cal – Display a calendar

cal

whoami – Display the current user

whoami

passwd – Change the current user’s password

passwd

su – Switch to another user

su user

sudo – Execute a command as another user

sudo command

vi – Edit a file

vi file.txt

nano – Edit a file

nano file.txt

grep – Search for a string in a file

grep "string" file.txt

awk – Process text

awk '{print $1}' file.txt

sed – Process text

sed 's/old/new/g' file.txt

tr – Translate characters

tr '[a-z]' '[A-Z]' < file.txt

diff – Compare two files

diff file1.txt file2.txt

patch – Apply a patch to a file

patch file.txt patch.diff

ln – Create a symbolic link

ln -s file.txt link.txt

chown – Change the owner of a file

chown user file.txt

chgrp – Change the group of a file

chgrp group file.txt

touch – Create an empty file

touch file.txt

echo – Print a string

echo "Hello World"

printf – Print a formatted string

printf "Hello %s\n" World

bc – Perform calculations

echo "2+2" | bc

history – Display the command history

history

man – Display the manual page for a command

man ls

which – Display the path of a command

which ls

type – Display the type of a command

type ls

alias – Create an alias for a command

alias ll='ls -l'

unalias – Remove an alias

unalias ll

export – Set an environment variable

export PATH=$PATH:/usr/local/bin

env – Display the environment variables

env

echo – Display the value of an environment variable

echo $PATH

source – Execute a script in the current shell

source script.sh

ssh-keygen – Generate an SSH key

ssh-keygen -t rsa -b 4096

ssh-copy-id – Copy an SSH key to a remote computer

ssh-copy-id user@host

rsync – Synchronize files between computers

rsync -avz user@host:/home/user/ ~/

nc – Network connection tool

nc -l -p 8080

telnet – Connect to a remote computer

telnet host 80

w – Display who is logged in

w

uptime – Display the system uptime

uptime

last – Display the last logged in users

last

lsof – List open files

lsof -i

netcat – Network connection tool

nc -l -p 8080

iptables – Configure the firewall

iptables -A INPUT -p tcp --dport 80 -j ACCEPT

dig – Query DNS

dig example.com

nslookup – Query DNS

nslookup example.com

host – Query DNS

host example.com

traceroute – Trace the route to a remote host

traceroute example.com

nmap – Scan a network

nmap -sV example.com

tmux – Multiplex terminal sessions

tmux

screen – Multiplex terminal sessions

screen

nohup – Run a command in the background

nohup command &

crontab – Schedule a command to run periodically

crontab -e

at – Schedule a command to run once

at now + 1 hour

watch – Execute a command periodically

watch -n 10 ls

dd – Copy a file

dd if=file.txt of=file.bak

tee – Redirect output to multiple files

ls | tee file1.txt file2.txt

ntpd – Synchronize the system clock

ntpd -q

logrotate – Rotate log files

logrotate -f /etc/logrotate.conf

rdate – Synchronize the system clock

rdate -s time.example.com

ntpdate – Synchronize the system clock

ntpdate -u time.example.com

chkconfig – Manage system services

chkconfig --list

system-config-services – Manage system services

system-config-services

iwconfig – Configure wireless network

iwconfig wlan0 essid "My Network"

iwlist – Scan for wireless networks

iwlist wlan0 scan

Conclusion

There are lot more commands in linux, this is just basics people who are looking for basic commands quick through, let us know your thoughts and inputs

Aslo read:

Veritas Volume Manager (VxVM) cheatsheet – https://computercarriage.com/2023/03/02/veritas-volume-manager-vxvm-cheatsheet/

Troubleshooting commands in Linux – https://computercarriage.com/2023/02/16/troubleshooting-commands-in-linux/

block devices using lsblk – https://computercarriage.com/2020/05/18/list-block-devices-using-lsblk-command/

tldp.org – https://tldp.org/LDP/abs/html/basic.html