Linux Commands Cheat Sheet — Essential Terminal Reference

Files & Directories

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ls -la

List all files with details

ls -lh

List files with human-readable sizes

cd /path/to/dir

Change directory

cd -

Go to previous directory

pwd

Print current directory

mkdir -p dir1/dir2/dir3

Create nested directories

cp -r source/ dest/

Copy directory recursively

mv old_name new_name

Move or rename file

rm -rf directory/

Remove directory recursively (careful!)

touch file.txt

Create empty file or update timestamp

ln -s target link_name

Create symbolic link

find / -name "*.log" -mtime +7

Find files modified more than 7 days ago

find . -type f -size +100M

Find files larger than 100MB

find . -name "*.tmp" -delete

Find and delete matching files

tree -L 2

Display directory tree (2 levels deep)

du -sh *

Disk usage of each item

df -h

Show disk space usage

File Viewing & Editing

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cat file.txt

Display file contents

less file.txt

View file with pagination

head -20 file.txt

Show first 20 lines

tail -f /var/log/syslog

Follow log file in real-time

wc -l file.txt

Count lines in file

diff file1 file2

Compare two files

sort file.txt | uniq -c | sort -rn

Count and sort unique lines

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

Print specific columns

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

Find and replace in file

cut -d',' -f1,3 data.csv

Extract columns from CSV

Search & Filter

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grep -r "pattern" /path/

Search recursively in files

grep -i "pattern" file.txt

Case-insensitive search

grep -n "pattern" file.txt

Show line numbers with matches

grep -v "pattern" file.txt

Show lines NOT matching pattern

grep -c "pattern" file.txt

Count matching lines

grep -E "pat1|pat2" file.txt

Extended regex (OR pattern)

which command

Find location of command

locate filename

Fast file search (requires updatedb)

Permissions & Ownership

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chmod 755 script.sh

rwxr-xr-x (owner: rwx, group+others: rx)

chmod +x script.sh

Add execute permission

chmod -R 644 /path/

Set permissions recursively

chown user:group file

Change file ownership

chown -R user:group /dir/

Change ownership recursively

Process Management

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ps aux

List all running processes

ps aux | grep nginx

Find specific process

top

Interactive process viewer

htop

Better interactive process viewer

jobs

List background jobs

bg %1 / fg %1

Send job to background/foreground

lsof -i :8080

Find process using port 8080

nohup command &

Run in background (survives logout)

Networking

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curl -s https://api.example.com

HTTP GET request

wget -O output.zip https://example.com/file.zip

Download file

ping -c 4 google.com

Test connectivity

traceroute google.com

Trace network path

nslookup domain.com

DNS lookup

dig domain.com

Detailed DNS lookup

ss -tulnp

Show listening ports

ip addr show

Show IP addresses

ssh user@host

Connect to remote server

scp file.txt user@host:/path/

Copy file to remote

rsync -avz src/ user@host:/dest/

Sync files (incremental)

Archives & Compression

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tar -czf archive.tar.gz dir/

Create gzipped archive

tar -xzf archive.tar.gz

Extract gzipped archive

tar -tf archive.tar.gz

List archive contents

zip -r archive.zip dir/

Create zip archive

unzip archive.zip

Extract zip archive

gzip file.txt

Compress file

gunzip file.txt.gz

Decompress gzip file

System Info

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uname -a

System information

hostname

Show hostname

uptime

System uptime

free -h

Memory usage

lsblk

List block devices

whoami

Current username

date

Current date and time

env

Show environment variables

Services & Systemd

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systemctl start nginx

Start a service

systemctl stop nginx

Stop a service

systemctl restart nginx

Restart a service

systemctl status nginx

Check service status

systemctl enable nginx

Enable service on boot

journalctl -u nginx -f

Follow service logs

journalctl --since "1 hour ago"

View recent system logs

Package Management

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apt update && apt upgrade

Update packages (Debian/Ubuntu)

apt install package

Install package (Debian/Ubuntu)

apt remove package

Remove package

apt search keyword

Search packages

yum install package

Install package (RHEL/CentOS)

snap install app

Install snap package

Bash Tricks

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!!

Repeat last command

Ctrl+R

Reverse search command history

history | tail -20

Show recent command history

command1 | command2

Pipe output to another command

command > file.txt

Redirect output (overwrite)

command >> file.txt

Redirect output (append)

cmd1 && cmd2

Run cmd2 only if cmd1 succeeds

cmd1 || cmd2

Run cmd2 only if cmd1 fails

alias ll='ls -la'

Create command alias

Cron Jobs

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crontab -e

Edit cron jobs

crontab -l

List cron jobs

*/5 * * * * /path/script.sh

Run every 5 minutes

0 2 * * * /path/backup.sh

Run daily at 2 AM

0 0 * * 0 /path/weekly.sh

Run every Sunday at midnight

@reboot /path/startup.sh

Run on system startup

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