Both path-aliasing files share the same format:
Blank lines and lines that begin with a # sign are skipped.
Each line, other than a blank line or a line preceded by #, must contain four strings separated by any number of blanks or tabs.
The first string specifies a source path, the second a submit host, the third an execution host, and the fourth the source path replacement.
Both the submit host and the execution host strings can be an * (asterisk), which matches any host.