soelim reads files lines by lines.
If a line starts by: “.so anotherfile” it replace the line by processing “anotherfile”. Otherwise the
line is printed to stdout.
-C Recognise .so when not followed by a space character.
-r Compatibility with GNU groff's soelim (does nothing).
-t Compatibility with GNU groff's soelim (does nothing).
-v Compatibility with GNU groff's soelim (does nothing).
-Idir This option specify directories where soelim searches for files (both those on the command line
and those named in “.so” directive.) This options may be specified multiple times. The
directories will be searched in the order specified.
The files are always searched first in the current directory.
A file specified with an absolute path will be opened directly without performing a search.