Common Linux Commands Cheat Sheet

1. ls – List Directory Contents

Syntax:
ls [options] [path]

Usage:
Displays the files and directories in the specified directory (current directory by default).

Common Switches:

  • -l: Long listing format (permissions, owner, size).
  • -a: Include hidden files (those starting with a dot).
  • -lh: Human-readable file sizes (e.g., KB, MB).
  • -R: List directories recursively.

2. cd – Change Directory

Syntax:
cd [path]

Usage:
Changes the current directory to the specified directory.

Common Switches:

  • ..: Go up one directory level.
  • -: Go to the previous directory.
  • ~: Go to the home directory.

3. pwd – Print Working Directory

Syntax:
pwd

Usage:
Displays the current directory’s full path.

4. mkdir – Make Directory

Syntax:
mkdir [options] [directory_name]

Usage:
Creates a new directory.

Common Switches:

  • -p: Create parent directories if they don’t exist.
  • -v: Show the directories being created.

5. rm – Remove Files or Directories

Syntax:
rm [options] [file_name]

Usage:
Removes files or directories.

Common Switches:

  • -r: Remove directories and their contents recursively.
  • -f: Force remove files (ignore nonexistent files and do not prompt).
  • -i: Prompt before every removal.

6. cp – Copy Files and Directories

Syntax:
cp [options] [source] [destination]

Usage:
Copies files or directories.

Common Switches:

  • -r: Copy directories recursively.
  • -i: Prompt before overwriting files.
  • -u: Copy only when the source file is newer than the destination file or if the destination file is missing.

7. mv – Move or Rename Files

Syntax:
mv [options] [source] [destination]

Usage:
Moves or renames files or directories.

Common Switches:

  • -i: Prompt before overwriting files.
  • -u: Move only when the source file is newer than the destination file or if the destination file is missing.
  • -v: Display the actions being performed.

8. touch – Create Empty File or Update Timestamp

Syntax:
touch [file_name]

Usage:
Creates an empty file or updates the timestamp of an existing file.

Common Switches:

  • -c: Do not create any files if they do not exist.
  • -t: Set a specific timestamp.

9. cat – Concatenate and Display Files

Syntax:
cat [file_name]

Usage:
Displays the contents of a file.

Common Switches:

  • -n: Number all output lines.
  • -b: Number non-blank lines.
  • -E: Display a dollar sign ($) at the end of each line.

10. echo – Display Text or Variables

Syntax:
echo [options] [string]

Usage:
Prints text or variables to the terminal.

Common Switches:

  • -n: Do not output the trailing newline.
  • -e: Enable interpretation of backslash escapes (e.g., \n for newline, \t for tab).
  • -E: Disable backslash escapes.

11. man – Display Manual Pages

Syntax:
man [command]

Usage:
Displays the manual page for a command, showing detailed usage.

12. find – Search for Files

Syntax:
find [path] [expression]

Usage:
Searches for files and directories based on criteria.

Common Switches:

  • -name [pattern]: Search for files by name.
  • -type [d|f]: Search for directories (d) or files (f).
  • -exec [command]: Execute a command on the found files.
  • -size [size]: Find files of a specific size.

13. grep – Search Text Using Patterns

Syntax:
grep [options] [pattern] [file]

Usage:
Searches for a pattern within files.

Common Switches:

  • -i: Case-insensitive search.
  • -r: Search recursively in directories.
  • -v: Invert the match (show lines that do not match the pattern).
  • -l: List only filenames that match the pattern.
  • -n: Show line numbers with matching lines.

14. ps – View Process Status

Syntax:
ps [options]

Usage:
Shows information about running processes.

Common Switches:

  • -e: Show all processes.
  • -f: Show full format listing.
  • -u [user]: Show processes belonging to a specific user.

15. top – Monitor System Processes

Syntax:
top

Usage:
Displays a real-time view of system processes and resource usage.

Common Switches:

  • -d [seconds]: Set the delay between updates.
  • -u [user]: Show processes for a specific user.

16. df – Display Disk Space Usage

Syntax:
df [options] [path]

Usage:
Shows the disk space usage of the file system.

Common Switches:

  • -h: Human-readable format (e.g., KB, MB).
  • -T: Show file system type.
  • -a: Include pseudo, duplicate, and inaccessible file systems.

17. du – Disk Usage

Syntax:
du [options] [path]

Usage:
Shows disk usage for directories.

Common Switches:

  • -h: Human-readable format (e.g., KB, MB).
  • -s: Show only the total size of the specified directory.
  • -a: Show disk usage for all files and directories.

18. chmod – Change File Permissions

Syntax:
chmod [options] [permissions] [file]

Usage:
Changes file or directory permissions.

Common Switches:

  • -R: Change permissions recursively.
  • -v: Verbosely show permissions being changed.

19. chown – Change File Owner and Group

Syntax:
chown [options] [user]:[group] [file]

Usage:
Changes the owner and group of a file or directory.

Common Switches:

  • -R: Change ownership recursively.
  • -v: Verbosely show ownership changes.

20. sudo – Execute Command as Superuser

Syntax:
sudo [command]

Usage:
Executes a command with superuser (root) privileges.

Common Switches:

  • -u [user]: Run the command as a different user.
  • -i: Start a shell with root privileges.
  • -s: Run the shell specified in the environment variable SHELL.

21. apt – Package Management (Debian-based Systems)

Syntax:
apt [options] [command]

Usage:
Manages packages on Debian-based systems.

Common Switches:

  • update: Update package list from repositories.
  • install [package]: Install a package.
  • remove [package]: Remove a package.
  • upgrade: Upgrade all installed packages.
  • search [package]: Search for a package.

22. yum – Package Management (RHEL/CentOS)

Syntax:
yum [options] [command]

Usage:
Manages packages on RHEL/CentOS-based systems.

Common Switches:

search [package]: Search for a package.

install [package]: Install a package.

remove [package]: Remove a package.

update: Update all installed packages.