Actually, exec might return, if 1) perl doesn't need to call the shell to execute the command (that is, exec is either given more than one argument, or a string which has no characters (except whitespace) that are special to the shell), and hence will call execvp directly, and 2) the command can't be called (usually because the file doesn't exists, or due to permission problems).

See perldoc -f exec.

Abigail