Bash Commands Cheatsheet

Essential bash commands. If this repo helped you in any way, consider giving it a star ⭐

Table of Contents

• Basic Command Structure
• File Navigation & Management
• File Viewing & Editing
• System Information
• File Permissions
• Process Management
• Environment & Variables
• Network
• Package Management
• Repository Commands
• Useful Combinations
• Script-Related
• Common Use Cases
• Safety Notes

Basic Command Structure

command [options] [arguments]    # General syntax
command --help                  # Get help for any command
man command                     # Show manual page
info command                   # Detailed documentation

File Navigation & Management

pwd                            # print working directory
ls -la                         # list all files with details
cd /path/to/dir               # change directory
mkdir -p dir1/dir2            # create nested directories
rm -rf dir                    # remove directory recursively (use with caution!)
cp -r src/ dest/              # copy directories recursively
mv old_name new_name          # move/rename files
touch file.txt                # create empty file
find . -name "*.py"           # find files by pattern
tree                          # display directory structure

File Viewing & Editing

cat file.txt                  # display file content
less file.txt                 # view file with pagination
head -n 5 file.txt           # show first 5 lines
tail -f file.log             # follow log file updates
grep "pattern" file          # search text in file
nano file.txt                # simple text editor
vim file.txt                 # advanced text editor
diff file1 file2             # compare files

System Information

top                          # process viewer
htop                         # enhanced process viewer
df -h                        # disk space usage
free -h                      # memory usage 
ps aux | grep python        # find python processes
which python3               # locate command
uname -a                    # system information
lsb_release -a             # distribution info
uptime                     # system uptime
lscpu                      # CPU information

File Permissions

chmod +x script.sh          # make script executable
chmod 755 file             # set permissions (rwxr-xr-x)
chown user:group file      # change file owner
chmod -R 644 dir          # recursively change files
chmod -R 755 dir          # recursively change directories
stat file                 # display file status

Process Management

ps aux                     # list all processes
kill -9 PID               # force kill process
bg                        # send process to background
fg                        # bring process to foreground
nohup command &           # run command after terminal closes
jobs                      # list background jobs
pgrep process_name        # find process ID
pkill process_name        # kill process by name

Environment & Variables

export PATH=$PATH:/dir    # add to PATH
echo $HOME               # print environment variable
source ~/.bashrc         # reload bash configuration
env                      # show all environment vars
printenv                 # print environment
set                      # show all shell variables

Network

ping google.com          # test connectivity
curl http://site.com     # http request
wget http://site.com     # download file
sudo netstat -tulpn      # show active ports
ssh user@hostname        # ssh connection
ifconfig                 # network interface config
ip addr                  # modern interface config
dig domain.com          # DNS lookup
traceroute domain.com   # trace packet route

Package Management (Ubuntu/Debian)

sudo apt update          # update package list 
sudo apt upgrade         # upgrade installed packages
sudo apt install pkg     # install package
sudo apt remove pkg      # remove package
sudo apt autoremove      # clean unused packages
apt search pkg           # search for package
apt show pkg            # show package details

Repository Commands

git init                 # initialize repository
git clone url           # clone repository
git status              # check status
git add .               # stage all changes
git commit -m "msg"     # commit with message
git push origin main    # push to remote
git pull               # update local repository

Useful Combinations

command1 | command2      # pipe output
command > file.txt       # redirect output to file
command >> file.txt      # append output to file
command1 && command2     # run if previous succeeds
command1 || command2     # run if previous fails
time command            # measure execution time

Script-Related

#!/bin/bash             # shebang line
set -e                  # exit on error
set -x                  # debug mode
$1, $2                  # script arguments
$?                      # last command exit status
$#                      # number of arguments
$$                      # process ID of the script
$@                      # all arguments
$0                      # script name

Common Use Cases

# Find and replace in files
find . -type f -name "*.txt" -exec sed -i 's/old/new/g' {} +

# Monitor system resources
watch -n 1 'free -h; echo; df -h'

# Search command history
history | grep "command"

# Compress/Extract
tar -czf archive.tar.gz dir/    # compress
tar -xzf archive.tar.gz         # extract

# Find large files
find / -type f -size +100M -exec ls -lh {} \;

Safety Notes

• Always double-check before using rm -rf
• Use rm -i for interactive deletion
• Back up important files before using chmod -R or chown -R
• Test scripts in isolated environment first
• Use sudo with caution
• Create backup before system changes: cp file{,.bak}
• Use --dry-run when available to test commands

License

MIT License - Feel free to share and modify with attribution.

Contributing

1. Fork the repository
2. Create your feature branch
3. Commit your changes
4. Push to the branch
5. Create a Pull Request

Please ensure your PR:

• Follows consistent formatting
• Includes clear descriptions
• Tests all commands
• Updates Table of Contents if needed

Feel free to submit issues and enhancement requests!