The Type command is used to find out the information about a Linux command. You can easily find whether the given command is an alias, shell built-in, file, function, or keyword using "type" command. Additionally, you can find the actual path of the command too.
Why would anyone need to find the command type? For instance, if you happen to work on a shared computer often, someone may intentionally or accidentally create an alias to a particular Linux command to perform an unwanted operation, for example "alias ls = rm -rf /". So, it is always good idea to inspect them before something worse happen. This is where the type command comes in help.
Let me show you some examples.
Type command usage
To find the type of ls command using type command, run:
$ type ls ls is aliased to `ls --color=auto'
As you can see in the above output, the "ls" command has been aliased to "ls --color-auto". It is harmless. But just think of if the ls command is aliased to something dangerous. You don't want that, do you?
You can use -t flag to find only the type of a Linux command. For example:
$ type -t ls alias
$ type -t mkdir file
$ type -t pwd builtin
$ type -t if keyword
$ type -t rvm function
This command just displays the type of the command, i.e alias. It doesn't display what is aliased to the given command. If a command is not found, you will see nothing in the terminal.
The another useful advantage of type command is we can easily find out the absolute path of a given Linux command. To do so, use -p flag as shown below.
$ type -p cal /usr/bin/cal
This is similar to 'which ls' command. If the given command is aliased, nothing will be printed.
To display all information of a command, use -a flag.
$ type -a ls ls is aliased to `ls --color=auto' ls is /usr/bin/ls ls is /bin/ls
As you see, -a flag displays the type of the given command and its absolute path.
So, what is the type of "type" command itself?
$ type type type is a shell builtin
For more details, refer the help section.
$ help type
