Linux Cheatsheet

Practical Linux command cheatsheet organized by category: file operations, text processing, networking, process management, disk usage, permissions, and more for quick reference

94 commands

ls

List files and directories

ls -la

cp

Copy files or directories

cp -r src/ dest/

mv

Move or rename files/directories

mv old.txt new.txt

rm

Remove files or directories

rm -rf directory/

touch

Create empty file or update timestamp

touch newfile.txt

cat

Display file contents

cat file.txt

less

View file contents page by page

less largefile.log

head

Display the beginning of a file

head -n 20 file.txt

tail

Display the end of a file

tail -f /var/log/syslog

ln

Create hard or symbolic links

ln -s /path/to/target link_name

file

Determine file type

file image.png

stat

Display detailed file information

stat file.txt

cd

Change directory

cd /var/log

pwd

Print working directory

pwd

mkdir

Create directories

mkdir -p parent/child/dir

rmdir

Remove empty directories

rmdir empty_dir

find

Search for files and directories

find / -name '*.log' -mtime -7

locate

Fast file search using database

locate nginx.conf

tree

Display directory tree structure

tree -L 2

du

Display directory disk usage

du -sh /var/*

chmod

Change file permissions

chmod 755 script.sh

chown

Change file owner

chown user:group file.txt

chgrp

Change file group

chgrp developers project/

umask

Set default file creation permissions

umask 022

setfacl

Set file access control lists

setfacl -m u:user:rwx file

getfacl

Get file access control lists

getfacl file.txt

ps

Display running processes

ps aux | grep nginx

top

Real-time process monitoring

top -u username

htop

Interactive process viewer

htop

kill

Send signal to a process

kill -9 1234

killall

Kill processes by name

killall nginx

bg

Resume stopped job in background

bg %1

fg

Bring background job to foreground

fg %1

nohup

Run command immune to hangups

nohup ./script.sh &

nice

Run command with modified priority

nice -n 10 ./heavy_task.sh

systemctl

Manage systemd services

systemctl restart nginx

ip

Manage network interfaces and routing

ip addr show

ping

Test network connectivity

ping -c 4 google.com

curl

Transfer data from/to a URL

curl -X POST -d '{"key":"val"}' https://api.example.com

wget

Download files from the web

wget https://example.com/file.tar.gz

ss

Display socket statistics

ss -tulnp

netstat

Display network connections and routing

netstat -tulnp

traceroute

Trace packet route to host

traceroute google.com

dig

DNS lookup utility

dig example.com MX

nslookup

Query DNS name servers

nslookup example.com

iptables

Manage firewall rules

iptables -L -n

scp

Secure copy over SSH

scp file.txt user@host:/path/

rsync

Efficiently sync files

rsync -avz src/ user@host:dest/

df

Display filesystem disk usage

df -h

mount

Mount a filesystem

mount /dev/sdb1 /mnt/usb

umount

Unmount a filesystem

umount /mnt/usb

fdisk

Manage disk partitions

fdisk -l

lsblk

List block devices

lsblk

mkfs

Create a filesystem (format)

mkfs.ext4 /dev/sdb1

fsck

Check and repair filesystem

fsck /dev/sda1

whoami

Display current username

whoami

id

Display user and group IDs

id username

useradd

Create a new user

useradd -m -s /bin/bash newuser

userdel

Delete a user

userdel -r username

usermod

Modify a user account

usermod -aG docker username

passwd

Change user password

passwd username

su

Switch to another user

su - root

sudo

Execute command as superuser

sudo apt update

groups

Display user's groups

groups username

apt update

Update package lists (Debian/Ubuntu)

sudo apt update

apt install

Install packages (Debian/Ubuntu)

sudo apt install nginx

apt remove

Remove packages (Debian/Ubuntu)

sudo apt remove nginx

apt upgrade

Upgrade installed packages (Debian/Ubuntu)

sudo apt upgrade

apt search

Search for packages (Debian/Ubuntu)

apt search nodejs

yum install

Install packages (RHEL/CentOS)

sudo yum install nginx

yum remove

Remove packages (RHEL/CentOS)

sudo yum remove nginx

yum update

Update packages (RHEL/CentOS)

sudo yum update

dnf install

Install packages (Fedora)

sudo dnf install nginx

uname

Display system information

uname -a

hostname

Display or set hostname

hostname -I

uptime

Display system uptime

uptime

date

Display or set date/time

date '+%Y-%m-%d %H:%M:%S'

free

Display memory usage

free -h

lscpu

Display CPU information

lscpu

dmesg

Display kernel messages

dmesg | tail -20

journalctl

View systemd journal logs

journalctl -u nginx -f

env

Display environment variables

env | grep PATH

export

Set environment variable

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

grep

Search for text patterns

grep -rn 'error' /var/log/

sed

Stream editor for text transformation

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

awk

Pattern scanning and text processing

awk '{print $1, $3}' file.txt

sort

Sort lines of text

sort -k2 -n file.txt

uniq

Remove or detect duplicate lines

sort file.txt | uniq -c

wc

Count lines, words, bytes

wc -l file.txt

cut

Extract fields from text

cut -d':' -f1 /etc/passwd

tr

Translate or delete characters

echo 'HELLO' | tr 'A-Z' 'a-z'

diff

Compare files line by line

diff file1.txt file2.txt

tee

Read stdin and write to stdout and files

echo 'log' | tee output.log

xargs

Build command arguments from stdin

find . -name '*.log' | xargs rm