Aside from system, which was properly recommended, there are several other ways to kick off an executable file. The one you choose depends on what you want the run to do in terms of IPC and process management.

The system function launches the external program in a new process and waits for it to end before proceeding with the rest of your script. It returns only an exit status.

The exec function takes off running the new executable in the same process, leaving the rest of your script behind. It never returns unless it failed. It's useful when all you wanted to do in perl was set up some environment variables, or some other kind of initialization. It's also useful after fork.

Backticks ($out = `foo`;) launch a command and return the captured STDOUT of that command for you to use as you like.

The open function has a pair of modes, '-|' and '|-', which let you launch a command as if it were a file to read or write. Your file operations serve to read from STDOUT or write to STDIN of the command. When used this way, open returns the pid of the child process.

There are also a number of modules which deliver different flavors of these. IPC::Run, Open2, and Open3 are three which provide more extensive IPC to system- and open-like commands.