type, which and whereis (Display Command Information)
There are several Linux commands that give you information about Linux commands besides the man command.
type – displays the type of a command
The type command returns types of commands. There are largely three types.
- Shell built-in command (internal command)
- External command (shell refers to the path of a command when it executes it)
- Alias
Here are examples of the three types.
Command Line - INPUT
type echo
Command Line - INTERACTIVE
echo is a shell builtin
Command Line - INPUT
type find
Command Line - INTERACTIVE
find is /usr/bin/find
Command Line - INPUT
type ll
Command Line - INTERACTIVE
ll is aliased to `ls -alF'
which – displays the path of a command
The which command gives you a file path of a command.
Command Line - INPUT
which sort
Command Line - RESPONSE
/usr/bin/sort
whereis – displays path of a command and related documents of the command
The whereis command is similar to the which command but gives you more information.
Command Line - INPUT
whereis sort
Command Line - RESPONSE
sort: /usr/bin/sort /usr/share/man/man1/sort.1.gz