Shell Build In Commands

Shell built-in commands are commands that are built into the shell itself, and they are executed directly by the shell without invoking external programs.

• cd - Used for changing the current working directory.
• echo - Displays text or variables to the terminal.
• export - Sets environment variables.
• unset - Removes environment variables.
• alias - Defines and displays aliases for commands.
• history - Shows command history.
• type - Displays information about a command (e.g., whether it's an alias, built-in, or external command).
• exit - Exits the current shell session.
• logout - Logs out of the current shell session (for login shells).
• source -(or dot): Executes commands from a script or file in the current shell environment.
• builtin - Displays a list of shell built-in commands.
• jobs - Lists background jobs.
• fg - Brings a background job to the foreground.
• bg - Resumes a background job.
• ulimit - Sets or displays user-level resource limits.
• exec - Replaces the current shell with a specified command, often used to execute a command without creating a new process.
• wait - Waits for background processes to finish.