linux-commands.md

Linux Commands Cheat Sheet

File and Directory Management

Navigation

• Change directory:
  cd /path/to/directory
• Go to the home directory:
  cd ~
• Go to the previous directory:
  cd -
• List files and directories:
  ls
• List detailed file info:
  ls -l
• List hidden files:
  ls -a

File Operations

• Copy files:
  cp source destination
• Copy directories:
  cp -r source_dir destination_dir
• Move or rename files:
  mv source destination
• Delete files:
  rm file.txt
• Delete directories:
  rm -r directory_name
• Create a new file:
  touch file.txt
• Create a new directory:
  mkdir directory_name
• Remove an empty directory:
  rmdir directory_name

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File Viewing and Editing

Viewing Files

• Display file content:
  cat file.txt
• View file content one page at a time:
  less file.txt
• Display the first 10 lines of a file:
  head file.txt
• Display the last 10 lines of a file:
  tail file.txt
• Follow a file in real-time:
  tail -f file.txt

Editing Files

• Edit files using nano:
  nano file.txt
• Edit files using vim:
  vim file.txt

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File Permissions and Ownership

Changing Permissions

• Change file permissions (e.g., rwx):
  chmod 755 file.txt
• Change directory permissions recursively:
  chmod -R 755 directory_name

Changing Ownership

• Change file owner:
  chown user file.txt
• Change file owner and group:
  chown user:group file.txt
• Change ownership recursively:
  chown -R user:group directory_name

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Searching and Finding Files

File Search

• Search for a file by name:
  find /path -name "filename"
• Search for files by extension:
  find /path -name "*.txt"

Content Search

• Search for text in a file:
  grep 'pattern' file.txt
• Search recursively in a directory:
  grep -r 'pattern' /path

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Disk and System Information

Disk Usage

• Check disk space usage:
  df -h
• Check directory or file size:
  du -sh /path

System Information

• Display system information:
  uname -a
• Show current logged-in users:
  who
• Display memory usage:
  free -h
• Show running processes:
  top
• Display detailed process list:
  ps aux

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Networking

Network Configuration

• Display IP address:
  ip addr
• Test network connectivity:
  ping example.com
• Display open network ports:
  netstat -tuln

File Transfers

• Copy files between systems:
  scp file.txt user@remote:/path
• Download files using wget:
  wget http://example.com/file.zip

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Process Management

Process Operations

• Show current running processes:
  ps aux
• Kill a process by PID:
  kill PID
• Kill a process by name:
  pkill process_name

Background and Foreground

• Run a command in the background:
  command &
• List background jobs:
  jobs
• Bring a background job to the foreground:
  fg %job_number

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User Management

User and Group Operations

• Add a new user:
  sudo useradd username
• Change a user's password:
  sudo passwd username
• Add a user to a group:
  sudo usermod -aG groupname username

Switching Users

• Switch to another user:
  su - username
• Execute a command as another user:
  sudo command

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Archiving and Compression

Creating Archives

• Create a .tar archive:
  tar -cvf archive.tar file_or_directory
• Create a compressed .tar.gz archive:
  tar -czvf archive.tar.gz file_or_directory

Extracting Archives

• Extract a .tar archive:
  tar -xvf archive.tar
• Extract a .tar.gz archive:
  tar -xzvf archive.tar.gz

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Package Management

Debian/Ubuntu (APT)

• Update package list:
  sudo apt update
• Upgrade all packages:
  sudo apt upgrade
• Install a package:
  sudo apt install package_name
• Remove a package:
  sudo apt remove package_name

Red Hat/CentOS (YUM/DNF)

• Install a package:
  sudo yum install package_name
sudo dnf install package_name
• Remove a package:
  sudo yum remove package_name
sudo dnf remove package_name

Arch Linux (Pacman)

• Update package list:
  sudo pacman -Sy
• Upgrade all packages:
• Install a package:
  sudo pacman -S package_name
• Remove a package:
• sudo pacman -R package_name
• Search for a package:
  pacman -Ss search_term

Arch Linux (yay)

• Install a package:
  yay -S package_name
• Remove a package: yay -R package_name
• Search for a package:
  yay -Ss search_term

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Shell Scripting

Variables and Scripts

• Assign a variable:
  variable_name="value"
• Print a variable:
  echo $variable_name
• Run a shell script:
  bash script.sh

Loops and Conditions

• Example for loop:

  for i in {1..5}; do
      echo $i
  done

• Example if statement:

  if [ condition ]; then
      echo "Condition met"
  fi

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Miscellaneous

History and Aliases

• Show command history:
  history
• Create a command alias:
  alias ll='ls -la'

Permissions and Ownership

• Display current working directory:
  pwd
• Change the hostname:
  sudo hostname new_hostname