Ubuntu Command Cheat Sheet – Essential Linux Commands

File & Directory Commands

Command	Description	Example
ls	List directory contents with details (permissions, owner, size)	ls -la
cd	Change current directory (use ~ for home directory)	cd /var/www
pwd	Print working directory (shows current path)	pwd
mkdir	Create new directory (use -p to create parent directories)	mkdir -p project/src
rm	Remove files/directories (-r for recursive, -f to force)	rm -rf temp/
cp	Copy files (-r for directories, -i for interactive)	cp -ri source/ destination/
mv	Move or rename files/directories	mv oldname.txt newname.txt
find	Search for files in directory hierarchy	find /home -name “*.txt”

User Management Commands

Command	Description	Example
adduser	Add a new user with interactive setup	sudo adduser john
useradd	Low-level utility for adding users	sudo useradd -m -s /bin/bash john
passwd	Change user password (root can change any password)	passwd john
usermod	Modify user account (add to groups, change shell, etc.)	sudo usermod -aG sudo john
deluser	Remove a user (–remove-home to delete home directory)	sudo deluser –remove-home john
groups	Show groups a user belongs to	groups john
id	Display user and group information	id john
whoami	Display current username	whoami

Command

Description

Example

adduser

Add a new user with interactive setup

sudo adduser john

useradd

Low-level utility for adding users

sudo useradd -m -s /bin/bash john

passwd

Change user password (root can change any password)

passwd john

usermod

Modify user account (add to groups, change shell, etc.)

sudo usermod -aG sudo john

deluser

Remove a user (–remove-home to delete home directory)

sudo deluser –remove-home john

groups

Show groups a user belongs to

groups john

Display user and group information

id john

whoami

Display current username

whoami

System Information Commands

Command	Description	Example
uname -a	Show all system information (kernel version, hostname, etc.)	uname -a
lsb_release -a	Display Ubuntu version information	lsb_release -a
top	Display Linux processes (dynamic real-time view)	top
htop	Interactive process viewer (install with sudo apt install htop)	htop
df -h	Show disk space usage in human-readable format	df -h
free -h	Show memory usage in human-readable format	free -h
uptime	Show how long the system has been running	uptime
hostnamectl	Show or set system hostname and related settings	hostnamectl

Command

Description

Example

uname -a

Show all system information (kernel version, hostname, etc.)

uname -a

lsb_release -a

Display Ubuntu version information

lsb_release -a

top

Display Linux processes (dynamic real-time view)

top

htop

Interactive process viewer (install with sudo apt install htop)

htop

df -h

Show disk space usage in human-readable format

df -h

free -h

Show memory usage in human-readable format

free -h

uptime

Show how long the system has been running

uptime

hostnamectl

Show or set system hostname and related settings

hostnamectl

Network Management Commands

Command	Description	Example
ip a	Show all IP addresses and interfaces	ip a
ip r	Display routing table	ip r
ping	Check connectivity to a host	ping google.com
traceroute	Trace route to a host	traceroute google.com
nslookup	Query DNS information	nslookup example.com
dig	Advanced DNS lookup tool	dig example.com
netstat	Display network connections	netstat -tuln
ss	Socket statistics (netstat replacement)	ss -tuln
nmcli	Control NetworkManager from command line	nmcli device status
nmtui	Text user interface for NetworkManager	nmtui
hostname	Display or set system hostname	hostname
ifconfig	Legacy command to view network interfaces	ifconfig
ethtool	Display or change Ethernet device settings	sudo ethtool eth0
iwconfig	Configure wireless network interfaces	iwconfig
ip link set	Enable or disable a network interface	sudo ip link set eth0 up
curl	Transfer data from or to a server	curl https://example.com
wget	Download files from the web	wget https://example.com/file.zip
tcpdump	Packet analyzer	sudo tcpdump -i eth0
nmap	Network scanner	nmap -sP 192.168.1.0/24
ufw	Uncomplicated Firewall utility	sudo ufw status

Command

Description

Example

ip a

Show all IP addresses and interfaces

ip a

ip r

Display routing table

ip r

ping

Check connectivity to a host

ping google.com

traceroute

Trace route to a host

traceroute google.com

nslookup

Query DNS information

nslookup example.com

dig

Advanced DNS lookup tool

dig example.com

netstat

Display network connections

netstat -tuln

Socket statistics (netstat replacement)

ss -tuln

nmcli

Control NetworkManager from command line

nmcli device status

nmtui

Text user interface for NetworkManager

nmtui

hostname

Display or set system hostname

hostname

ifconfig

Legacy command to view network interfaces

ifconfig

ethtool

Display or change Ethernet device settings

sudo ethtool eth0

iwconfig

Configure wireless network interfaces

iwconfig

ip link set

Enable or disable a network interface

sudo ip link set eth0 up

curl

Transfer data from or to a server

curl https://example.com

wget

Download files from the web

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

tcpdump

Packet analyzer

sudo tcpdump -i eth0

nmap

Network scanner

nmap -sP 192.168.1.0/24

ufw

Uncomplicated Firewall utility

sudo ufw status

Package Management Commands

Command	Description	Example
sudo apt update	Update package list	sudo apt update
sudo apt upgrade	Upgrade all upgradable packages	sudo apt upgrade
sudo apt install	Install a package	sudo apt install nginx
sudo apt remove	Remove a package	sudo apt remove nginx
sudo apt purge	Remove package with config files	sudo apt purge nginx
sudo apt autoremove	Remove unnecessary packages	sudo apt autoremove
apt list –installed	List all installed packages	apt list –installed
apt show	Show package details	apt show nginx
dpkg -i	Install a .deb file	sudo dpkg -i package.deb
dpkg -r	Remove a package	sudo dpkg -r nginx
dpkg -l	List installed .deb packages	dpkg -l
dpkg -s	Get package status	dpkg -s nginx
snap install	Install a Snap package	sudo snap install code –classic
snap remove	Remove a Snap package	sudo snap remove code
snap list	List installed Snap packages	snap list
flatpak install	Install a Flatpak package	flatpak install flathub org.gimp.GIMP
flatpak uninstall	Uninstall a Flatpak package	flatpak uninstall org.gimp.GIMP
flatpak list	List installed Flatpak apps	flatpak list
apt-cache search	Search for packages	apt-cache search nginx
apt-mark hold	Prevent a package from being upgraded	sudo apt-mark hold nginx

Command

Description

Example

sudo apt update

Update package list

sudo apt update

sudo apt upgrade

Upgrade all upgradable packages

sudo apt upgrade

sudo apt install

Install a package

sudo apt install nginx

sudo apt remove

Remove a package

sudo apt remove nginx

sudo apt purge

Remove package with config files

sudo apt purge nginx

sudo apt autoremove

Remove unnecessary packages

sudo apt autoremove

apt list –installed

List all installed packages

apt list –installed

apt show

Show package details

apt show nginx

dpkg -i

Install a .deb file

sudo dpkg -i package.deb

dpkg -r

Remove a package

sudo dpkg -r nginx

dpkg -l

List installed .deb packages

dpkg -l

dpkg -s

Get package status

dpkg -s nginx

snap install

Install a Snap package

sudo snap install code –classic

snap remove

Remove a Snap package

sudo snap remove code

snap list

List installed Snap packages

snap list

flatpak install

Install a Flatpak package

flatpak install flathub org.gimp.GIMP

flatpak uninstall

Uninstall a Flatpak package

flatpak uninstall org.gimp.GIMP

flatpak list

List installed Flatpak apps

flatpak list

apt-cache search

Search for packages

apt-cache search nginx

apt-mark hold

Prevent a package from being upgraded

sudo apt-mark hold nginx

Permissions & Ownership Commands

Command	Description	Example
chmod	Change file/directory permissions	chmod 755 file.txt
chmod -R	Recursively change permissions	chmod -R 755 /var/www
chown	Change file owner and group	sudo chown john:john file.txt
chown -R	Recursively change owner/group	sudo chown -R www-data:www-data /var/www
chgrp	Change group ownership	sudo chgrp staff file.txt
umask	Set default permissions for new files	umask 022
ls -l	List files with permissions	ls -l
stat	Display detailed file info	stat file.txt
getfacl	Get ACL permissions	getfacl file.txt
setfacl	Set ACL permissions	setfacl -m u:john:rwx file.txt
chmod +x	Make a file executable	chmod +x script.sh
chmod -x	Remove executable permission	chmod -x script.sh
chmod 000	Revoke all permissions	chmod 000 file.txt
chmod 644	Set read/write for owner, read-only for others	chmod 644 file.txt
chmod 700	Set full permissions for owner only	chmod 700 file.txt
find -perm	Find files with specific permissions	find / -type f -perm 0777
sudo visudo	Edit sudoers file safely	sudo visudo
sudo usermod -aG	Add user to a group	sudo usermod -aG sudo john
groups	Show groups for a user	groups john
whoami	Show current user	whoami

Command

Description

Example

chmod

Change file/directory permissions

chmod 755 file.txt

chmod -R

Recursively change permissions

chmod -R 755 /var/www

chown

Change file owner and group

sudo chown john:john file.txt

chown -R

Recursively change owner/group

sudo chown -R www-data:www-data /var/www

chgrp

Change group ownership

sudo chgrp staff file.txt

umask

Set default permissions for new files

umask 022

ls -l

List files with permissions

ls -l

stat

Display detailed file info

stat file.txt

getfacl

Get ACL permissions

getfacl file.txt

setfacl

Set ACL permissions

setfacl -m u:john:rwx file.txt

chmod +x

Make a file executable

chmod +x script.sh

chmod -x

Remove executable permission

chmod -x script.sh

chmod 000

Revoke all permissions

chmod 000 file.txt

chmod 644

Set read/write for owner, read-only for others

chmod 644 file.txt

chmod 700

Set full permissions for owner only

chmod 700 file.txt

find -perm

Find files with specific permissions

find / -type f -perm 0777

sudo visudo

Edit sudoers file safely

sudo visudo

sudo usermod -aG

Add user to a group

sudo usermod -aG sudo john

groups

Show groups for a user

groups john

whoami

Show current user

whoami

Process Management Commands

Command	Description	Example
ps	Display active processes	ps aux
top	Real-time process viewer	top
htop	Interactive process viewer (advanced)	htop
kill	Terminate a process by PID	kill 1234
killall	Kill all processes by name	killall firefox
nice	Launch a process with priority	nice -n 10 myscript.sh
renice	Change priority of a running process	renice -n 5 -p 1234
pidof	Get PID of a process	pidof nginx
pgrep	Find PID(s) by process name	pgrep apache2
pkill	Kill processes by name	pkill -f chrome
watch	Run a command repeatedly	watch -n 1 free -h
bg	Resume a background job	bg %1
fg	Bring background job to foreground	fg %1
jobs	List current user jobs	jobs
&	Run command in background	./longtask.sh &
disown	Remove job from shell job table	disown %1
strace	Trace system calls and signals	strace -p 1234
lsof	List open files by processes	lsof -i :80
systemctl	Manage services/processes	systemctl status apache2
timeout	Run command with a time limit	timeout 10s ping google.com
grep	Search for patterns in files using regular expressions	grep “search_term” filename.txt
grep -r	Recursively search for a pattern in all files under a directory	grep -r “error” /var/log
grep -i	Search for a pattern, ignoring case sensitivity	grep -i “warning” logs.txt
sed	Stream editor for filtering and transforming text	sed ‘s/old/new/g’ file.txt
sed -n	Suppress automatic printing and print only matching lines	sed -n ‘/pattern/p’ file.txt
awk	Pattern scanning and processing language for files	awk ‘{print $1}’ file.txt
awk -F	Set the field separator for input data	awk -F “:” ‘{print $1}’ /etc/passwd

Command

Description

Example

Display active processes

ps aux

top

Real-time process viewer

top

htop

Interactive process viewer (advanced)

htop

kill

Terminate a process by PID

kill 1234

killall

Kill all processes by name

killall firefox

nice

Launch a process with priority

nice -n 10 myscript.sh

renice

Change priority of a running process

renice -n 5 -p 1234

pidof

Get PID of a process

pidof nginx

pgrep

Find PID(s) by process name

pgrep apache2

pkill

Kill processes by name

pkill -f chrome

watch

Run a command repeatedly

watch -n 1 free -h

Resume a background job

bg %1

Bring background job to foreground

fg %1

jobs

List current user jobs

jobs

Run command in background

./longtask.sh &

disown

Remove job from shell job table

disown %1

strace

Trace system calls and signals

strace -p 1234

lsof

List open files by processes

lsof -i :80

systemctl

Manage services/processes

systemctl status apache2

timeout

Run command with a time limit

timeout 10s ping google.com

grep

Search for patterns in files using regular expressions

grep “search_term” filename.txt

grep -r

Recursively search for a pattern in all files under a directory

grep -r “error” /var/log

grep -i

Search for a pattern, ignoring case sensitivity

grep -i “warning” logs.txt

sed

Stream editor for filtering and transforming text

sed ‘s/old/new/g’ file.txt

sed -n

Suppress automatic printing and print only matching lines

sed -n ‘/pattern/p’ file.txt

awk

Pattern scanning and processing language for files

awk ‘{print $1}’ file.txt

awk -F

Set the field separator for input data

awk -F “:” ‘{print $1}’ /etc/passwd

Disk Management Commands

Command	Description	Example
df	Show disk space usage	df -h
du	Estimate file and directory space usage	du -sh *
lsblk	List information about block devices	lsblk
fdisk	Partition a disk	sudo fdisk /dev/sda
parted	Manage disk partitions	sudo parted /dev/sdb
mount	Mount a filesystem	sudo mount /dev/sdb1 /mnt
umount	Unmount a filesystem	sudo umount /mnt
mkfs	Create a new filesystem	sudo mkfs.ext4 /dev/sdb1
fsck	Check and repair a filesystem	sudo fsck /dev/sda1
blkid	Get block device attributes (UUID, type)	sudo blkid
tune2fs	Adjust tunable filesystem parameters	sudo tune2fs -l /dev/sda1
mount -a	Mount all filesystems defined in fstab	sudo mount -a
df -T	Show disk usage with filesystem type	df -T
ncdu	Interactive disk usage analyzer	ncdu /
findmnt	Find mounted filesystems	findmnt
ls -lh	List files with human-readable sizes	ls -lh /var/log
stat	Show detailed file or filesystem info	stat filename
udisksctl	Manage disks with UDisks2	udisksctl mount -b /dev/sdb1
df –total	Show total disk space used	df -h –total
mount \| column -t	View mounted drives in formatted output	mount \| column -t

Command

Description

Example

Show disk space usage

df -h

Estimate file and directory space usage

du -sh *

lsblk

List information about block devices

lsblk

fdisk

Partition a disk

sudo fdisk /dev/sda

parted

Manage disk partitions

sudo parted /dev/sdb

mount

Mount a filesystem

sudo mount /dev/sdb1 /mnt

umount

Unmount a filesystem

sudo umount /mnt

mkfs

Create a new filesystem

sudo mkfs.ext4 /dev/sdb1

fsck

Check and repair a filesystem

sudo fsck /dev/sda1

blkid

Get block device attributes (UUID, type)

sudo blkid

tune2fs

Adjust tunable filesystem parameters

sudo tune2fs -l /dev/sda1

mount -a

Mount all filesystems defined in fstab

sudo mount -a

df -T

Show disk usage with filesystem type

df -T

ncdu

Interactive disk usage analyzer

ncdu /

findmnt

Find mounted filesystems

findmnt

ls -lh

List files with human-readable sizes

ls -lh /var/log

stat

Show detailed file or filesystem info

stat filename

udisksctl

Manage disks with UDisks2

udisksctl mount -b /dev/sdb1

df –total

Show total disk space used

df -h –total

mount | column -t

View mounted drives in formatted output

mount | column -t

Systemd & systemctl Commands

Command	Description	Example
systemctl status	Show the status of a service	systemctl status apache2
systemctl start	Start a service	sudo systemctl start nginx
systemctl stop	Stop a service	sudo systemctl stop nginx
systemctl restart	Restart a service	sudo systemctl restart apache2
systemctl reload	Reload service config without restarting	sudo systemctl reload apache2
systemctl enable	Enable a service to start on boot	sudo systemctl enable nginx
systemctl disable	Disable a service from starting on boot	sudo systemctl disable nginx
systemctl is-active	Check if a service is active	systemctl is-active mysql
systemctl is-enabled	Check if a service is enabled	systemctl is-enabled ssh
systemctl list-units	List all loaded units	systemctl list-units
systemctl list-unit-files	List all unit files and states	systemctl list-unit-files
systemctl daemon-reexec	Re-exec systemd manager	sudo systemctl daemon-reexec
systemctl daemon-reload	Reload systemd configuration	sudo systemctl daemon-reload
systemctl mask	Prevent a service from being started	sudo systemctl mask apache2
systemctl unmask	Unblock a previously masked service	sudo systemctl unmask apache2
systemctl reboot	Reboot the system	sudo systemctl reboot
systemctl poweroff	Power off the system	sudo systemctl poweroff
systemctl suspend	Suspend the system	sudo systemctl suspend
journalctl	View logs managed by systemd	journalctl -xe
systemctl show	Show properties of a systemd unit	systemctl show ssh

Command

Description

Example

systemctl status

Show the status of a service

systemctl status apache2

systemctl start

Start a service

sudo systemctl start nginx

systemctl stop

Stop a service

sudo systemctl stop nginx

systemctl restart

Restart a service

sudo systemctl restart apache2

systemctl reload

Reload service config without restarting

sudo systemctl reload apache2

systemctl enable

Enable a service to start on boot

sudo systemctl enable nginx

systemctl disable

Disable a service from starting on boot

sudo systemctl disable nginx

systemctl is-active

Check if a service is active

systemctl is-active mysql

systemctl is-enabled

Check if a service is enabled

systemctl is-enabled ssh

systemctl list-units

List all loaded units

systemctl list-units

systemctl list-unit-files

List all unit files and states

systemctl list-unit-files

systemctl daemon-reexec

Re-exec systemd manager

sudo systemctl daemon-reexec

systemctl daemon-reload

Reload systemd configuration

sudo systemctl daemon-reload

systemctl mask

Prevent a service from being started

sudo systemctl mask apache2

systemctl unmask

Unblock a previously masked service

sudo systemctl unmask apache2

systemctl reboot

Reboot the system

sudo systemctl reboot

systemctl poweroff

Power off the system

sudo systemctl poweroff

systemctl suspend

Suspend the system

sudo systemctl suspend

journalctl

View logs managed by systemd

journalctl -xe

systemctl show

Show properties of a systemd unit

systemctl show ssh

Popular Ubuntu Tools

Tool	Description	Example
htop	Interactive system process viewer	sudo apt install htop
ncdu	Disk usage analyzer with ncurses interface	sudo apt install ncdu
curl	Transfer data from or to a server	sudo apt install curl
wget	Download files from web via CLI	sudo apt install wget
git	Version control system	sudo apt install git
neofetch	Display system info in terminal	sudo apt install neofetch
ufw	Uncomplicated Firewall management	sudo apt install ufw
nmap	Network scanner and security auditing tool	sudo apt install nmap
tree	Display directories as trees	sudo apt install tree
tmux	Terminal multiplexer	sudo apt install tmux
zsh	Powerful shell alternative to bash	sudo apt install zsh
oh-my-zsh	ZSH configuration framework	sh -c “$(curl -fsSL https://raw.github.com/ohmyzsh/ohmyzsh/master/tools/install.sh)”
docker	Containerization platform	sudo apt install docker.io
snap	Install and manage snap packages	sudo apt install snapd
flatpak	Manage Flatpak applications	sudo apt install flatpak
gparted	Partition management GUI tool	sudo apt install gparted
bleachbit	System cleaner and privacy tool	sudo apt install bleachbit
timeshift	System restore tool	sudo apt install timeshift
vim	Powerful terminal-based text editor	sudo apt install vim
gnome-tweaks	Customize GNOME desktop settings	sudo apt install gnome-tweaks
remmina	Remote desktop client	sudo apt install remmina
virtualbox	Open-source virtualization tool	sudo apt install virtualbox
gnome-disk-utility	Manage drives and partitions via GUI	sudo apt install gnome-disk-utility
synaptic	Advanced package manager GUI	sudo apt install synaptic
alacritty	GPU-accelerated terminal emulator	sudo apt install alacritty
bat	cat command with syntax highlighting	sudo apt install bat
fd	Simple, fast alternative to find	sudo apt install fd-find
ripgrep	Fast search tool like grep	sudo apt install ripgrep
lazygit	Terminal UI for Git	sudo snap install lazygit

Tool

Description

Example

htop

Interactive system process viewer

sudo apt install htop

ncdu

Disk usage analyzer with ncurses interface

sudo apt install ncdu

curl

Transfer data from or to a server

sudo apt install curl

wget

Download files from web via CLI

sudo apt install wget

git

Version control system

sudo apt install git

neofetch

Display system info in terminal

sudo apt install neofetch

ufw

Uncomplicated Firewall management

sudo apt install ufw

nmap

Network scanner and security auditing tool

sudo apt install nmap

tree

Display directories as trees

sudo apt install tree

tmux

Terminal multiplexer

sudo apt install tmux

zsh

Powerful shell alternative to bash

sudo apt install zsh

oh-my-zsh

ZSH configuration framework

sh -c “$(curl -fsSL https://raw.github.com/ohmyzsh/ohmyzsh/master/tools/install.sh)”

docker

Containerization platform

sudo apt install docker.io

snap

Install and manage snap packages

sudo apt install snapd

flatpak

Manage Flatpak applications

sudo apt install flatpak

gparted

Partition management GUI tool

sudo apt install gparted

bleachbit

System cleaner and privacy tool

sudo apt install bleachbit

timeshift

System restore tool

sudo apt install timeshift

vim

Powerful terminal-based text editor

sudo apt install vim

gnome-tweaks

Customize GNOME desktop settings

sudo apt install gnome-tweaks

remmina

Remote desktop client

sudo apt install remmina

virtualbox

Open-source virtualization tool

sudo apt install virtualbox

gnome-disk-utility

Manage drives and partitions via GUI

sudo apt install gnome-disk-utility

synaptic

Advanced package manager GUI

sudo apt install synaptic

alacritty

GPU-accelerated terminal emulator

sudo apt install alacritty

bat

cat command with syntax highlighting

sudo apt install bat

Simple, fast alternative to find

sudo apt install fd-find

ripgrep

Fast search tool like grep

sudo apt install ripgrep

lazygit

Terminal UI for Git

sudo snap install lazygit