codex-lv2-may-2025

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Clearing the Screen and Getting Help

⚠️ macOS Users: On macOS, ls --help does not work. You can skip this lesson and use man instead (covered in the next lesson). For example, try man ls to see the manual for the ls command.

Steps

  1. Clear the screen If your terminal gets too cluttered, type:

    clear

    Then press Enter. This doesn’t delete anything — it just gives you a blank screen to work on. You can still scroll up or use the up arrow (↑) and down arrow (↓) to go through your previous commands.

  2. Get help using --help Many commands support a --help option. This prints out a short guide. Try this:

    ls --help

    You’ll see a list of options and explanations. Example:

    Usage: ls [OPTION]... [FILE]...
-a, --all       show all files, including hidden ones
-F, --classify  add / for folders, * for executables
...

  3. Use the man command (manual pages) On macOS and Linux, you can also use man to open a full manual for the command:

    man ls

    Use the arrow keys to move. Press q to quit and return to the shell.

  4. Know which help method to use

    • Use --help for most regular commands (works in Git Bash and Linux).
    • Use man if available (macOS and Linux).

    • If you try man cd and it says:

      No manual entry for cd

      Then try:

      help cd

      The help command shows help for built-in Bash commands like cd.

  5. Understand command options Some commands have both short and long options. For example:

    • Short: -F
    • Long: --classify

    When to use each:

    • Use short options like -F when typing quickly in the terminal.
    • Use long options like --classify when writing scripts so they are easier to read.

  6. What happens with invalid options If you make a typo or use an unsupported option, you’ll get an error. Example:

    $ ls -j
ls: invalid option -- 'j'
Try 'ls --help' for more information.

Notes