home..

Linux Commands

(831 Words, 5 Minutes)

File and Directory Management

• ls – List directory contents
• pwd – Print current working directory
• cd [directory] – Change directory
• mkdir [dir] – Create a new directory
• rmdir [dir] – Remove an empty directory
• rm -r [dir/file] – Remove directory or file recursively
• cp [source] [destination] – Copy files or directories
• mv [source] [destination] – Move/rename files
• find [path] -name [filename] – Search for files by name

---

File Operations

• cat [file] – Display file contents
• tac [file] – Display file contents in reverse
• less [file] – View file content page by page
• more [file] – Similar to less, but less advanced
• head -n [num] [file] – Show first n lines of a file
• tail -n [num] [file] – Show last n lines of a file
• touch [file] – Create an empty file or update timestamp
• stat [file] – Display file metadata
• diff [file1] [file2] – Compare two files

---

Permissions and Ownership

• ls -l – Show file permissions and ownership
• chmod [mode] [file] – Change file permissions (chmod 755 file)
• chown [user]:[group] [file] – Change file owner
• chgrp [group] [file] – Change file group

---

Process Management

• ps aux – Show running processes
• top – Display real-time process usage
• htop – Interactive process viewer (if installed)
• kill [PID] – Terminate process by PID
• killall [name] – Kill all processes by name
• pkill [pattern] – Kill processes matching a pattern
• jobs – Show background jobs
• fg – Bring background job to foreground
• bg – Resume a background job
• nohup [command] & – Run a process in the background

---

Networking

• ip a – Show IP address configuration
• ifconfig – Deprecated alternative to ip a
• ping [host] – Test network connection
• curl [url] – Fetch data from a URL
• wget [url] – Download files
• netstat -tulnp – Show open ports and services
• ss -tulnp – Modern alternative to netstat
• traceroute [host] – Trace network path to a host
• nslookup [domain] – Query DNS records

---

User Management

• whoami – Show current user
• who – Show logged-in users
• id [user] – Show user’s UID and GID
• su [user] – Switch to another user
• sudo [command] – Run command as superuser
• passwd [user] – Change user password
• useradd [user] – Create a new user
• usermod -aG [group] [user] – Add user to a group
• userdel [user] – Delete a user

---

Disk and Storage

• df -h – Show disk space usage
• du -sh [dir] – Show size of a directory
• mount [device] [mountpoint] – Mount a filesystem
• umount [device] – Unmount a filesystem
• lsblk – List all block devices
• fdisk -l – Show disk partitions
• mkfs.ext4 /dev/[device] – Format a disk partition

---

Package Management

Debian/Ubuntu (APT)

• apt update – Update package lists
• apt upgrade – Upgrade all installed packages
• apt install [package] – Install a package
• apt remove [package] – Remove a package

Arch Linux (Pacman)

• pacman -Syu – Sync and update system
• pacman -S [package] – Install package
• pacman -R [package] – Remove package

Red Hat/CentOS (Yum/DNF)

• yum update or dnf update – Update packages
• yum install [package] – Install package
• yum remove [package] – Remove package

---

System Monitoring

• uptime – Show system uptime
• free -h – Show memory usage
• vmstat – Show system performance metrics
• iostat – Show CPU and disk I/O stats
• dmesg | tail – Show kernel logs
• journalctl -xe – Show detailed system logs
• history – Show command history

---

Archiving and Compression

• tar -cvf archive.tar [file/dir] – Create tar archive
• tar -xvf archive.tar – Extract tar archive
• tar -czvf archive.tar.gz [file/dir] – Create tar.gz archive
• tar -xzvf archive.tar.gz – Extract tar.gz archive
• zip [file.zip] [file] – Create ZIP archive
• unzip [file.zip] – Extract ZIP archive

---

Text Processing

• grep [pattern] [file] – Search text in a file
• awk '{print $1}' file – Process text by columns
• sed 's/old/new/g' file – Replace text in a file
• cut -d':' -f1 /etc/passwd – Extract fields from text
• sort [file] – Sort file content
• uniq [file] – Remove duplicate lines

---

Shell Scripting and Automation

• echo "Hello" – Print text
• read var – Take user input
• export VAR=value – Set environment variable
• crontab -e – Edit cron jobs
• chmod +x script.sh – Make script executable
• ./script.sh – Run a script

---

Miscellaneous

• alias ll='ls -lah' – Create alias
• unalias ll – Remove alias
• time [command] – Measure execution time
• watch -n 5 [command] – Run command every 5 seconds
• yes | command – Auto-confirm prompts
• sleep 5 – Wait for 5 seconds