What are common built-in commands?

Common built-in commands in Linux include:

1. cd: Changes the current directory.
2. pwd: Prints the current working directory.
3. echo: Displays a line of text or variable values.
4. history: Shows the command history for the current session.
5. alias: Creates shortcuts for commands.
6. export: Sets environment variables for child processes.
7. set: Configures shell options and positional parameters.
8. unset: Removes variables or functions.
9. fg: Brings a background job to the foreground.
10. bg: Sends a job to the background.

These commands are integral to shell operation and can manipulate the shell environment directly. If you have more questions or need examples of how to use any of these commands, feel free to ask!