Find the correct path to an executable file in Unix

Several Unix dialects use the whereis command to find where programs, or executables, are stored in the file structure of the computer. To use it at the Unix prompt, enter:

  whereis command

Replace command with the name of the executable for which you are looking. For example, if you are looking for the location of the lpr command, you would enter:

  whereis lpr

The whereis command will return something like the following:

  lpr: /usr/ucb/lpr /usr/man/man1/lpr.1

In this example, the query asked about the lpr command, which spools jobs to printers. The operating system returned two answers, and thus two paths. The first path is the location of the lpr executable, and the second path is the location of the lpr manual page.

To find the path the operating system uses to execute a command when you enter it on the command line, use the which command instead, for example:

  which lpr

This command will output something like the following:

  /var/bsd/lpr

This means that when you enter lpr at the command line, the system is really executing /var/bsd/lpr.