How to use the command 'type' (with examples)

The ’type’ command is used to display the type of command that the shell will execute. It can be useful when troubleshooting issues related to command execution or when you want to know where a specific command is located.

Use case 1: Display the type of a command

Code:

type command

Motivation: We might want to verify the type of a specific command to understand how it will be executed by the shell. This can be helpful when dealing with aliases, functions, or built-in commands that may have the same name as a regular executable.

Explanation: This use case simply involves running the ’type’ command followed by the name of the command we want to check. The shell will then display the type of the command.

Example output:

$ type ls
ls is /usr/bin/ls

In this example, the ’type’ command is used to check the type of the ’ls’ command. The output indicates that ’ls’ is located at ‘/usr/bin/ls’, confirming that it is an executable file.

Use case 2: Display all locations containing the specified executable

Code:

type -a command

Motivation: When there are multiple locations containing an executable with the same name, we may want to see all the available options. By using the ‘-a’ option with the ’type’ command, we can list all the locations where the executable is found.

Explanation: To display all the locations containing the specified executable, we can use the ’type -a’ command followed by the name of the command. The shell will then list the paths where the executable is located.

Example output:

$ type -a ls
ls is aliased to `ls --color=auto'
ls is /usr/bin/ls

In this example, the ’type -a’ command is used to display all the locations containing the ’ls’ command. The output shows that ’ls’ has an alias defined as ’ls –color=auto’ and is also located at ‘/usr/bin/ls’.

Use case 3: Display the name of the disk file that would be executed

Code:

type -p command

Motivation: When you want to know the exact file that would be executed when running a command, you can use the ‘-p’ option with the ’type’ command. This can be useful when troubleshooting issues related to the execution of a specific command or when you need to provide the full path to a command.

Explanation: To display the name of the disk file that would be executed, we can use the ’type -p’ command followed by the name of the command. The shell will then show the path to the command.

Example output:

$ type -p ls
/usr/bin/ls

In this example, the ’type -p’ command is used to display the name of the disk file that would be executed when running the ’ls’ command. The output shows the path ‘/usr/bin/ls’.

Conclusion:

The ’type’ command is a useful tool for understanding how commands will be executed by the shell. It allows you to check the type of a command, display all locations containing the specified executable, and find the name of the disk file that would be executed. By using these different use cases, you can gain insights into the behavior of commands and troubleshoot any related issues more effectively.