Common Linux Commands

The Linux command line is a text interface to your computer. Often called the shell, terminal, console, or prompt, it can appear complex at first. But being able to copy and paste commands, combined with the power and flexibility the command line offers, makes it essential when following instructions online — including many on this site.

New to the shell? Prefix any command below with man (for example, man ls) to read its full manual, and press q to exit.

File and Directory Management

• ls - List directory contents

  ls
  ls -l
  ls -lh
  ls -la
  

• cd - Change directory

  cd /path/to/directory
  cd ..
  cd ~
  cd -
  

• pwd - Print working directory

  pwd
  

• mkdir - Create a new directory

  mkdir directory_name
  mkdir -p /path/to/nested/directory
  

• rmdir - Remove an empty directory

  rmdir directory_name
  

• rm - Remove files or directories

  rm file_name
  rm -i file_name
  rm -r directory_name
  rm -rf directory_name
  

• cp - Copy files or directories

  cp source_file destination_file
  cp -i source_file destination_file
  cp -r source_directory destination_directory
  

• mv - Move or rename files or directories

  mv source_file destination_file
  mv -i source_file destination_file
  mv old_directory_name new_directory_name
  

• touch - Create an empty file or update its timestamp

  touch file_name
  

• ln - Create links between files

  ln -s /path/to/target link_name
  

• find - Search for files in a directory hierarchy

  find /path/to/search -name "file_name"
  find /path -type f -name "*.log"
  find /path -type d -name "cache"
  find . -name "*.tmp" -delete
  

• tree - Display directories as a tree

  tree
  tree -L 2
  tree -a
  

There is no recycle bin on the command line. rm -rf deletes permanently and without confirmation. Double-check the path before running it, and never run rm -rf with a wildcard or a variable you haven’t verified (rm -rf $DIR/ becomes rm -rf / if $DIR is empty).

cp and mv overwrite the destination silently. Add -i to be prompted before replacing an existing file. The same applies to find ... -delete — test the match with find ... -print first.

File Viewing and Editing

• cat - Concatenate and display file content

  cat file_name
  cat file1 file2 > combined.txt
  

• less - View file content one screen at a time

  less file_name
  

• more - View file content one screen at a time

  more file_name
  

• head - Display the first lines of a file

  head file_name
  head -n 20 file_name
  

• tail - Display the last lines of a file

  tail file_name
  tail -n 20 file_name
  tail -f /var/log/syslog
  

• grep - Search text using patterns

  grep "pattern" file_name
  grep -i "pattern" file_name
  grep -n "pattern" file_name
  grep -r "pattern" /path/to/search
  

• wc - Count lines, words, and bytes

  wc file_name
  wc -l file_name
  

• nano - Simple text editor in the terminal

  nano file_name
  

• vi or vim - Advanced text editor in the terminal

  vi file_name
  vim file_name
  

tail -f follows a file as it grows, which is the quickest way to watch a log in real time. Press Ctrl+C to stop.

Stuck in vim? Press Esc, then type :wq to save and quit or :q! to quit without saving. If cat on a binary file scrambles your terminal, run reset to restore it.

System Information and Management

• top - Display real-time system information

  top
  

• ps - Display information about active processes

  ps
  ps aux
  ps aux | grep process_name
  

• df - Display disk space usage

  df
  df -h
  

• du - Estimate file space usage

  du
  du -h
  du -sh directory_name
  

• free - Display memory usage

  free
  free -h
  

• uptime - Show how long the system has been running

  uptime
  

• uname - Display system information

  uname
  uname -a
  

• systemctl - Manage services on systemd distributions

  systemctl status service_name
  systemctl start service_name
  systemctl stop service_name
  systemctl restart service_name
  systemctl enable service_name
  

Add -h to df, du, and free for human-readable sizes (KB/MB/GB instead of raw blocks). In top, press q to quit; htop is a friendlier alternative if it’s installed.

systemctl start, stop, restart, and enable change system state and require sudo. status is read-only and safe to run as a normal user.

Networking

• ping - Send ICMP ECHO_REQUEST to network hosts

  ping host_name_or_ip
  ping -c 4 host_name_or_ip
  

• ifconfig - Configure a network interface

  ifconfig
  

• ip - Show/manipulate routing, devices, and tunnels

  ip address
  ip a
  ip link
  ip route
  

• netstat - Network statistics

  netstat
  netstat -tuln
  

• ss - Investigate sockets

  ss
  ss -tuln
  

• scp - Securely copy files between hosts

  scp source_file user@remote_host:/path/to/destination
  scp -r source_directory user@remote_host:/path/to/destination
  

• wget - Non-interactive network downloader

  wget url
  wget -O output_name url
  

• curl - Transfer data from or to a server

  curl url
  curl -O url
  curl -L url
  

• lsof - List open files, useful to check ports

  lsof -i :port_number
  

• kill - Terminate a process by PID

  kill pid
  kill -9 pid
  

ifconfig and netstat are deprecated on modern distributions and may not be installed. Use ip in place of ifconfig and ss in place of netstat.

kill -9 sends SIGKILL, which the process cannot catch or clean up after — it can leave temp files or corrupt state behind. Try a plain kill (SIGTERM) first and only escalate to -9 if the process ignores it.

Package Management

• apt-get - APT package handling utility (Debian/Ubuntu)

  sudo apt-get update
  sudo apt-get install package_name
  sudo apt-get remove package_name
  

• yum - Package manager (Red Hat/CentOS)

  sudo yum update
  sudo yum install package_name
  sudo yum remove package_name
  

• dnf - Package manager (Fedora)

  sudo dnf update
  sudo dnf install package_name
  sudo dnf remove package_name
  

Run the update command before installing so you pull the latest package versions. On recent Debian/Ubuntu systems, apt is the modern front end and can replace apt-get in these examples.

Permissions and Ownership

• sudo - Run a command as the superuser

  sudo command
  

• chmod - Change file modes or Access Control Lists

  chmod 755 file_name
  chmod +x script.sh
  chmod -R 755 directory_name
  

• chown - Change file owner and group

  chown user_name:group_name file_name
  chown -R user_name:group_name directory_name
  

Avoid chmod 777 — it makes a file writable and executable by everyone, which is a common security hole. Grant the least access that works (often 644 for files, 755 for directories and scripts).

Recursive changes (-R) apply to every file underneath the target. Running chmod -R or chown -R on the wrong directory — for example a system path like / or /etc — can render the system unbootable. Confirm the path first.

Archiving and Compression

• tar - Store, list, or extract files in an archive

  tar -cvf archive_name.tar directory_name
  tar -xvf archive_name.tar
  tar -czvf archive_name.tar.gz directory_name
  tar -xzvf archive_name.tar.gz
  

• zip - Package and compress files

  zip archive_name.zip file1 file2
  zip -r archive_name.zip directory_name
  

• unzip - Extract files from a ZIP archive

  unzip archive_name.zip
  unzip archive_name.zip -d /path/to/destination
  

The tar flags are easier to remember as a mnemonic: create, extract, gzip compression, verbose output, and file (the archive name, which must come last). So “create a gzipped archive verbosely from a file” is -czvf.

Miscellaneous

• echo - Display a line of text

  echo "Hello, World!"
  echo $HOME
  

• date - Display or set the system date and time

  date
  date -s "2024-07-31 12:34:56"
  

• whoami - Print the current user name

  whoami
  

• which - Locate a command’s executable

  which command_name
  

• man - Display the manual for a command

  man command_name
  

• history - Display the command history

  history
  

• clear - Clear the terminal screen

  clear
  

date -s sets the clock manually, requires root, and will fight an NTP time-sync service if one is running. On most systems, let NTP manage the time instead.

Speed up recall: press Ctrl+R to search your history interactively, and type !! to rerun the previous command. Avoid pasting passwords or tokens on the command line, since they are saved in history in plain text.