Linux Type Command

In this guide, we will learn more about the “type” command in Linux.

Prerequisites:

To perform the steps that are demonstrated in this guide, you need the following components:

A properly configured Linux system. Check out how to create a Linux VM for testing and learning purposes.
Basic understanding of the command-line interface

The Type Command in Linux

Unlike other Linux-specific commands (for example: ls, chmod, shutdown, vi, grep, pwd, etc.), the “type” command is a built-in Bash function that displays an info on the type of the command that is provided as an argument.

$ type type

Besides Bash, other shells (Zsh, Ksh, etc.) also come with their own implementation of the “type” command.

Basic Usage

The command structure of type is as follows:

$ type <option> <argument>

The simplest usage is to provide a command as an argument.

$ type which

The “type” command can also work with multiple arguments at once.

$ type type which cd ls chmod sudo sleep shutdown

Command Types

If we are interested in only the type of the command, use the “-t” flag to get the command type only.

$ type -t echo

$ type -t type

$ type -t while

$ type -t grep

The output is one of the following command types:

alias: A shell alias.
function: A built-in shell function.
builtin: A built-in shell command.
file: A disk file.
keyword: A reserved word for shell-specific functions.

Displaying All Locations

Various commands on Linux exist as both a standalone executable file and a built-in shell function. We can determine if a command has both characteristics using the “type” command.

Check out the following example:

$ type -a echo

Here, as the output suggests, the “echo” command is a built-in shell function as well as an executable file (located at “/usr/bin/echo”).

Other Options

Besides the options that are mentioned so far, the “type” command comes with some additional ones.

The “-p” Flag

Run the following commands:

$ type -p echo

$ type -p shutdown

Here, the “type” command won’t show any output if the given argument is a shell built-in. Otherwise, the output will be the location of the command’s executable file.

The “-P” Flag

Check out the following examples:

$ type -P echo pwd

$ type -P if while

Here, the “type” command will search for the given arguments in all the PATH locations and return the location of the matching executable files.

In this example, both “echo” and “pwd” commands have dedicated binaries. Both “if” and “while” are shell keywords and have no dedicated binary. So, the output is empty.

Exit Codes

After performing its task, the “type” command leaves behind an exit code. Using the exit code, we can determine if the task is successful or not.

0: The command runs successfully and without any error.
1: The command faces an error.

The following commands demonstrate the exit codes:

$ type type

$ echo $?

$ type asdfg

$ echo $?

Conclusion

In this guide, we demonstrated how to use the “type” command in Linux. It’s a shell built-in command that describes the nature of a command.

Interested in learning more about other Linux commands? Check out the Linux commands sub-category. For more Bash-related guides, check out about Bash programming instead.

Happy computing!