Introduction to the Linux Command Line

1. Editing Commands with Readline

Bash uses the Readline library, which supports rich editing, navigation, and clipboard operations directly from the terminal.

Cursor Movement Keys

Key	Action
Ctrl+A	Move to beginning of line
Ctrl+E	Move to end of line
Ctrl+F / →	Forward one character
Ctrl+B / ←	Backward one character
Alt+F	Forward one word
Alt+B	Backward one word
Ctrl+L	Clear screen

Text Editing Shortcuts

Key	Action
Ctrl+D	Delete current character
Ctrl+T	Transpose character with previous
Alt+T	Transpose current and previous word
Alt+L	Lowercase to end of word
Alt+U	Uppercase to end of word

2. Cutting and Pasting with Kill & Yank

Text is cut into a buffer (kill-ring) and pasted using:

Key	Action
Ctrl+K	Kill to end of line
Ctrl+U	Kill to beginning of line
Alt+D	Kill to end of word
Alt+Backspace	Kill to beginning of word
Ctrl+Y	Yank (paste) last killed text

3. Autocompletion with Tab

Pressing TAB completes filenames, commands, directories, and more:

ls l[TAB] → ls-output.txt
ls Do[TAB] → Documents

Supported Completions:

• File/directory paths
• Environment variables like $HO[TAB]
• Usernames ~user
• System commands
• Hosts from /etc/hosts

Additional Keys:

Key	Action
Alt + ?	List all completions
Alt + *	Insert all matching items

4. Command History Management

history | less
history | grep /usr/bin
!88          # Run command number 88

Interactive Search (Ctrl+R):

• Ctrl+R → Start reverse search
• Ctrl+J → Insert and edit command
• Ctrl+G → Cancel search

Navigation Shortcuts

Key	Action
Ctrl+P / ↑	Previous command
Ctrl+N / ↓	Next command
Alt+<	First command in history
Alt+>	Last command in history
Ctrl+O	Run current command and move to next

5. History Expansion with !

Pattern	Action
!!	Run last command
!number	Run specific numbered command
!string	Run last command starting with string
!?string	Run last command containing string

⚠ Caution: History expansion can trigger unexpected results. Always verify before executing.

6. Recording a Terminal Session

script log.txt        # Saves all terminal activity to log.txt
exit                  # Stop recording

Conclusion

Bash power users rely on the keyboard and its rich shortcut set to streamline their workflow. By mastering Readline edits, autocompletion, history tricks, and efficient command expansion, you can elevate your shell experience to pro level—where speed meets precision.