Essential Daily Commands

These are the commands you'll use every day as a Linux user. Master these and you'll be productive on any Linux system.

Navigation Essentials

pwd                     # Where am I?
ls                      # What's here?
cd directory            # Go somewhere
cd ..                   # Go up
cd ~                    # Go home
cd -                    # Go back

File Operations Essentials

cat file.txt            # View file
less file.txt           # Page through file
head -n 10 file.txt     # First 10 lines
tail -n 10 file.txt     # Last 10 lines
touch newfile.txt       # Create file
mkdir newdir            # Create directory
cp source dest          # Copy
mv source dest          # Move/rename
rm file.txt             # Delete

Quick File Viewing

# Preview beginning
head file.txt

# Watch end (logs)
tail -f log.txt

# Count lines
wc -l file.txt

Finding Things

find . -name "*.txt"           # Find files
grep "pattern" file.txt        # Search in file
grep -r "pattern" .            # Search recursively
which command                  # Where is command?

System Information

uname -a                # System info
hostname                # Computer name
whoami                  # Current user
date                    # Current date/time
uptime                  # System uptime
df -h                   # Disk space
free -h                 # Memory usage

Process Management

ps aux                  # List processes
top                     # Monitor system
kill PID                # Stop process

Exercise: Daily Workflow

Run a series of common commands:

Network Commands

ping google.com         # Test connectivity
curl url                # Fetch URL
wget url                # Download file
ssh user@host           # Remote login
scp file user@host:     # Copy to remote

File Permissions

chmod +x script.sh      # Make executable
chmod 755 file          # rwxr-xr-x
chown user:group file   # Change owner
ls -l                   # View permissions

Text Processing

sort file.txt           # Sort lines
uniq file.txt           # Remove duplicates
cut -d',' -f1 file.csv  # Extract column
tr 'a-z' 'A-Z'          # Transform characters

Getting Help

man command             # Manual page
command --help          # Quick help
info command            # Info page
type command            # Command type

Daily Maintenance

# Update system (Debian/Ubuntu)
sudo apt update && sudo apt upgrade

# Check disk space
df -h

# Check memory
free -h

# Check logs
tail -f /var/log/syslog

Useful Aliases

Add to ~/.bashrc:

alias ll='ls -la'
alias la='ls -A'
alias ..='cd ..'
alias ...='cd ../..'
alias update='sudo apt update && sudo apt upgrade'
alias ports='netstat -tulanp'

Key Takeaways

• pwd, ls, cd for navigation
• cat, less, head, tail for viewing files
• find and grep for searching
• ps and top for processes
• man for help on any command