Linux Basic Commands Cheatsheet

System Information

uname -a Display all system information including kernel version, hostname, and architecture

uname -r Show kernel release version

uname -m Display machine hardware architecture

hostname Show or set system hostname

hostnamectl Query and change system hostname and related settings

uptime Show how long system has been running and load average

whoami Display current username

id Show user ID and group ID information

w Display who is logged in and what they are doing

who Show who is logged in

last Show listing of last logged in users

date Display or set system date and time

cal Display calendar

df -h Show disk space usage in human-readable format

df -i Show inode usage

du -sh Show disk usage summary in human-readable format

du -sh * Show disk usage for all items in current directory

free -h Display memory usage in human-readable format

top Display real-time system resource usage and processes

htop Interactive process viewer with better interface than top

ps aux Show all running processes with detailed information

ps -ef Display all processes in full format

pstree Show processes in tree format

Navigation and Directory Operations

pwd Print working directory path

cd Change to home directory

cd .. Move up one directory level

cd ../.. Move up two directory levels

cd - Change to previous directory

cd ~ Change to home directory

cd /path/to/directory Change to specific directory

ls List directory contents

ls -l List with detailed information in long format

ls -a List all files including hidden files

ls -la List all files with detailed information

ls -lh List with human-readable file sizes

ls -lt List sorted by modification time newest first

ls -ltr List sorted by modification time oldest first

ls -R List recursively including subdirectories

ls -d */ List only directories in current location

tree Display directory tree structure

tree -L 2 Display directory tree limited to two levels deep

dirs Show directory stack

pushd /path Push directory onto stack and change to it

popd Pop directory from stack and change to it

File Operations

touch filename Create empty file or update timestamp

cat filename Display file contents

cat file1 file2 Concatenate and display multiple files

tac filename Display file contents in reverse order

more filename View file contents one screen at a time

less filename View file contents with backward navigation capability

head filename Display first ten lines of file

head -n 20 filename Display first twenty lines of file

tail filename Display last ten lines of file

tail -n 20 filename Display last twenty lines of file

tail -f filename Follow file and display new lines as they are added

cp source destination Copy file to destination

cp -r source_dir dest_dir Copy directory recursively

cp -i source destination Copy with interactive prompt before overwrite

cp -u source destination Copy only when source is newer than destination

cp -v source destination Copy with verbose output

mv source destination Move or rename file

mv -i source destination Move with interactive prompt before overwrite

mv -u source destination Move only when source is newer than destination

rm filename Remove file

rm -i filename Remove with interactive confirmation

rm -f filename Force remove without confirmation

rm -r directory Remove directory and contents recursively

rm -rf directory Force remove directory and contents without confirmation

mkdir dirname Create directory

mkdir -p path/to/nested/directory Create nested directories including parents

rmdir dirname Remove empty directory

ln -s source linkname Create symbolic link

ln source linkname Create hard link

stat filename Display detailed file information and statistics

file filename Determine file type

basename /path/to/file Extract filename from path

dirname /path/to/file Extract directory path from full path

File Viewing and Editing

nano filename Edit file with nano text editor

vi filename Edit file with vi editor

vim filename Edit file with vim editor

gedit filename Edit file with gedit graphical editor

code filename Open file in Visual Studio Code

diff file1 file2 Compare two files line by line

diff -u file1 file2 Compare files with unified format output

sdiff file1 file2 Compare files side by side

cmp file1 file2 Compare two files byte by byte

comm file1 file2 Compare sorted files line by line

File Permissions and Ownership

chmod 755 filename Change file permissions using numeric notation

chmod u+x filename Add execute permission for user owner

chmod g-w filename Remove write permission for group

chmod o+r filename Add read permission for others

chmod -R 755 directory Change permissions recursively for directory

chown user:group filename Change file owner and group

chown user filename Change file owner only

chown -R user:group directory Change ownership recursively for directory

chgrp group filename Change group ownership of file

umask Display default permission mask

umask 022 Set default permission mask

Searching and Finding

find /path -name filename Find files by name

find /path -iname filename Find files by name case-insensitive

find /path -type f Find only files

find /path -type d Find only directories

find /path -size +100M Find files larger than one hundred megabytes

find /path -mtime -7 Find files modified in last seven days

find /path -user username Find files owned by specific user

find /path -name “*.txt” -delete Find and delete files matching pattern

find /path -perm 777 Find files with specific permissions

locate filename Find files by name using database

updatedb Update locate database

which command Show full path of command

whereis command Show binary, source, and manual page locations

type command Display information about command type

Text Processing and Manipulation

grep pattern filename Search for pattern in file

grep -i pattern filename Search case-insensitive

grep -r pattern directory Search recursively in directory

grep -n pattern filename Show line numbers with matches

grep -v pattern filename Show lines not matching pattern

grep -c pattern filename Count matching lines

grep -l pattern files* List files containing pattern

grep -w pattern filename Match whole words only

grep -A 3 pattern filename Show three lines after match

grep -B 3 pattern filename Show three lines before match

grep -C 3 pattern filename Show three lines before and after match

egrep pattern filename Extended grep with regular expressions

fgrep pattern filename Fixed string grep without regex interpretation

sort filename Sort lines alphabetically

sort -r filename Sort in reverse order

sort -n filename Sort numerically

sort -u filename Sort and remove duplicates

sort -k 2 filename Sort by second column

sort -t: -k3 -n filename Sort by third field using colon delimiter numerically

uniq filename Remove adjacent duplicate lines

uniq -c filename Count occurrences of duplicate lines

uniq -d filename Show only duplicate lines

uniq -u filename Show only unique lines

wc filename Count lines, words, and characters

wc -l filename Count lines only

wc -w filename Count words only

wc -c filename Count bytes only

cut -d: -f1 filename Extract first field using colon delimiter

cut -c1-10 filename Extract characters one through ten

paste file1 file2 Merge lines of files side by side

join file1 file2 Join lines of files on common field

tr ‘a-z’ ‘A-Z’ < filename Translate lowercase to uppercase

tr -d ‘0-9’ < filename Delete all digits

tr -s ‘ ‘ < filename Squeeze repeated spaces to single space

sed ‘s/old/new/’ filename Replace first occurrence of old with new on each line

sed ‘s/old/new/g’ filename Replace all occurrences of old with new

sed -i ‘s/old/new/g’ filename Replace in file and save changes

sed -n ‘10,20p’ filename Print lines ten through twenty

sed ‘5d’ filename Delete line five

awk ‘{print $1}’ filename Print first field of each line

awk -F: ‘{print $1}’ filename Print first field using colon delimiter

awk ‘/pattern/ {print $0}’ filename Print lines matching pattern

awk ‘NR==10’ filename Print line ten

awk ‘{sum+=$1} END {print sum}’ filename Sum values in first column

Archiving and Compression

tar -cvf archive.tar directory Create tar archive

tar -xvf archive.tar Extract tar archive

tar -tvf archive.tar List contents of tar archive

tar -czvf archive.tar.gz directory Create compressed tar gzip archive

tar -xzvf archive.tar.gz Extract tar gzip archive

tar -cjvf archive.tar.bz2 directory Create compressed tar bzip2 archive

tar -xjvf archive.tar.bz2 Extract tar bzip2 archive

gzip filename Compress file with gzip

gzip -d filename.gz Decompress gzip file

gunzip filename.gz Decompress gzip file

bzip2 filename Compress file with bzip2

bzip2 -d filename.bz2 Decompress bzip2 file

bunzip2 filename.bz2 Decompress bzip2 file

zip archive.zip files Create zip archive

zip -r archive.zip directory Create zip archive recursively

unzip archive.zip Extract zip archive

unzip -l archive.zip List contents of zip archive

7z a archive.7z files Create 7z archive

7z x archive.7z Extract 7z archive

Network Operations

ping hostname Send ICMP echo requests to test connectivity

ping -c 4 hostname Ping four times then stop

ifconfig Display or configure network interfaces

ip addr Show IP addresses and network interfaces

ip link Show network interface status

ip route Show routing table

netstat -tuln Show listening ports

netstat -ant Show all network connections

ss -tuln Show listening sockets

ss -ant Show all sockets

curl url Transfer data from URL

curl -O url Download file from URL

curl -I url Fetch HTTP headers only

wget url Download file from URL

wget -c url Continue interrupted download

scp file user@host:/path Securely copy file to remote host

scp user@host:/path/file . Securely copy file from remote host

rsync -avz source destination Synchronize files and directories

rsync -avz source user@host:/path Synchronize to remote host

ssh user@host Connect to remote host via SSH

ssh -p port user@host Connect using specific port

nslookup domain Query DNS for domain information

dig domain DNS lookup utility

host domain DNS lookup simple output

traceroute hostname Show path packets take to destination

route -n Display routing table

arp -a Show ARP cache

Process Management

ps Show processes for current shell

ps aux Show all processes with details

ps -ef Show all processes in full format

ps -u username Show processes for specific user

pgrep process_name Find process ID by name

pidof process_name Find process ID of running program

kill pid Terminate process by ID

kill -9 pid Force kill process

killall process_name Kill all processes by name

pkill process_name Kill processes matching pattern

bg Resume suspended job in background

fg Bring background job to foreground

jobs List background jobs

nohup command & Run command immune to hangups in background

nice -n 10 command Run command with modified priority

renice -n 5 -p pid Change priority of running process

watch command Execute command repeatedly and display results

watch -n 5 command Execute command every five seconds

screen Start screen session for persistent terminal

tmux Start tmux session for terminal multiplexing

Package Management for Debian and Ubuntu

apt update Update package index

apt upgrade Upgrade all packages

apt full-upgrade Upgrade with package removal if needed

apt install package Install package

apt remove package Remove package keeping configuration

apt purge package Remove package including configuration

apt autoremove Remove unused dependencies

apt search keyword Search for packages

apt show package Show package details

apt list –installed List installed packages

apt list –upgradable List upgradable packages

dpkg -i package.deb Install deb package file

dpkg -r package Remove package

dpkg -l List installed packages

dpkg -L package List files installed by package

dpkg -S filename Find package owning file

Package Management for Red Hat and CentOS

yum update Update all packages

yum install package Install package

yum remove package Remove package

yum search keyword Search for packages

yum info package Show package information

yum list installed List installed packages

dnf update Update all packages with dnf

dnf install package Install package with dnf

dnf remove package Remove package with dnf

rpm -i package.rpm Install rpm package

rpm -e package Remove rpm package

rpm -qa List all installed rpm packages

rpm -ql package List files in package

rpm -qf filename Find package owning file

User and Group Management

useradd username Create new user

useradd -m username Create user with home directory

useradd -s /bin/bash username Create user with specific shell

userdel username Delete user

userdel -r username Delete user including home directory

usermod -aG group username Add user to group

usermod -s /bin/zsh username Change user shell

passwd Change current user password

passwd username Change password for specific user

groupadd groupname Create new group

groupdel groupname Delete group

groups Show groups current user belongs to

groups username Show groups for specific user

id username Show user ID and group memberships

su Switch to root user

su - username Switch to user with login shell

sudo command Execute command as root

sudo -u user command Execute command as specific user

sudo -i Start interactive root shell

visudo Edit sudoers file safely

System Control and Services

systemctl start service Start systemd service

systemctl stop service Stop systemd service

systemctl restart service Restart systemd service

systemctl reload service Reload service configuration

systemctl status service Show service status

systemctl enable service Enable service to start at boot

systemctl disable service Disable service from starting at boot

systemctl list-units List all active units

systemctl list-unit-files List all unit files

journalctl View systemd journal logs

journalctl -u service View logs for specific service

journalctl -f Follow journal logs in real-time

journalctl -b Show logs from current boot

service service_name start Start service using init script

service service_name stop Stop service using init script

service service_name status Check service status

reboot Reboot system

shutdown -h now Shutdown system immediately

shutdown -r now Restart system immediately

shutdown -h +10 Shutdown in ten minutes

poweroff Power off system

halt Halt system

init 0 Shutdown system using runlevel

init 6 Restart system using runlevel

Disk and Filesystem Management

fdisk -l List all disk partitions

fdisk /dev/sda Partition disk interactively

parted /dev/sda Partition disk with parted

mkfs.ext4 /dev/sda1 Create ext4 filesystem

mkfs.xfs /dev/sda1 Create xfs filesystem

mount /dev/sda1 /mnt Mount filesystem

mount -t nfs server:/path /mnt Mount NFS share

umount /mnt Unmount filesystem

blkid Show block device attributes

lsblk List block devices in tree format

fsck /dev/sda1 Check and repair filesystem

e2fsck /dev/sda1 Check ext filesystem

tune2fs -l /dev/sda1 Show ext filesystem parameters

resize2fs /dev/sda1 Resize ext filesystem

dd if=/dev/sda of=/dev/sdb Copy disk to disk

dd if=/dev/zero of=file bs=1M count=100 Create file filled with zeros

Environment Variables

echo $PATH Display PATH variable

echo $HOME Display home directory variable

echo $USER Display current username variable

env Display all environment variables

printenv Display all environment variables

export VAR=value Set environment variable

export PATH=$PATH:/new/path Add to PATH variable

unset VAR Remove environment variable

source filename Execute commands from file in current shell

. filename Execute commands from file in current shell

Input Output Redirection

command > file Redirect stdout to file overwriting

command » file Redirect stdout to file appending

command 2> file Redirect stderr to file

command &> file Redirect both stdout and stderr to file

command > file 2>&1 Redirect stdout and stderr to same file

command < file Redirect file as stdin

command « EOF Here document for multi-line input

command 2>&1 | tee file Redirect to file and stdout simultaneously

command | command2 Pipe stdout of first command to stdin of second

command 2>&1 | command2 Pipe both stdout and stderr to next command

command > /dev/null Discard stdout

command 2> /dev/null Discard stderr

command &> /dev/null Discard all output

Wildcards and Pattern Matching

filename Match any characters

file?.txt Match single character

file[abc].txt Match any one character in brackets

file[a-z].txt Match any character in range

file[!abc].txt Match any character not in brackets

{file1,file2}.txt Brace expansion for multiple patterns

file{1..10}.txt Brace expansion with sequence

Command History and Shortcuts

history Display command history

history 20 Display last twenty commands

!number Execute command by history number

!! Execute previous command

!string Execute most recent command starting with string

!$ Reference last argument of previous command

!* Reference all arguments of previous command

ctrl-r Search command history interactively

ctrl-c Cancel current command

ctrl-z Suspend current process

ctrl-d Logout or end input

ctrl-l Clear screen

tab Autocomplete commands and filenames

Miscellaneous Useful Commands

clear Clear terminal screen

reset Reset terminal to default state

tty Print terminal device name

alias name=’command’ Create command alias

unalias name Remove alias

history -c Clear command history

script filename Record terminal session to file

bc Command-line calculator

expr 5 + 3 Evaluate arithmetic expression

factor number Display prime factors

yes string Output string repeatedly

seq start end Generate sequence of numbers

shuf filename Shuffle lines randomly

rev filename Reverse characters in each line

column -t filename Format output into columns

split -l 100 filename Split file into pieces of one hundred lines each

csplit file pattern Split file at pattern matches

xargs Build and execute commands from stdin

xargs -I {} command {} Execute command for each input line

parallel command ::: args Execute commands in parallel

time command Measure command execution time

timeout 10 command Run command with time limit

sleep 5 Delay for five seconds

wait Wait for background processes to complete

cron Schedule recurring tasks

crontab -e Edit cron jobs for current user

crontab -l List cron jobs

at now + 5 minutes Schedule one-time task

batch Execute commands when load permits