🧠 Linux command Built-in Tutorial

The command built-in in Linux is used to run a command while bypassing shell function lookup. It ensures that you're executing the actual binary or built-in command, not a shell alias or function with the same name.

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📋 Basic Syntax

command [options] <command_name> [arguments...]

• <command_name>: The command you want to run.
• arguments: Arguments passed to the command.
• options: Modify behavior (e.g., -v, -V, -p).

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🔧 Common Options

Option	Description
-v	Print the command that would be executed
-V	Print detailed information about the command
-p	Use a default value for PATH, ignoring shell functions and aliases

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🧪 Examples

1. Run a command while ignoring shell functions or aliases

command ls

This runs the actual ls binary, even if ls is aliased (e.g., alias ls='ls --color=auto').

2. Check what will be executed

command -v ls

Returns the path to the ls binary, e.g., /bin/ls.

3. Get verbose information about a command

command -V cd

Might return: cd is a shell builtin.

4. Use command to bypass a function

myfunc() { echo "This is a function"; }
command myfunc  # Will fail if no binary named `myfunc` exists

5. Use command with -p to ignore custom PATH

command -p ls

Runs ls using a default PATH, useful in restricted environments.

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🧠 Why Use command?

• To bypass aliases or functions that override standard commands.
• To ensure consistency in scripts by calling the original command.
• To debug shell behavior when a command isn't acting as expected.

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📚 References

• GNU Bash Manual: command
• Linuxize: Bash Builtins
• GeeksforGeeks: command Built-in in Linux
• man7.org: bash(1) Manual

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Happy scripting! 🧑‍💻

Let me know if you'd like a version that includes comparisons with `builtin` or `type`!