A fish-friendly source version of gvp's gvp in and gvp out commands.
Currently there are no automated installation options. However, gvp-fish is
just a fish script. Put it wherever you want.
Fish requires a file to be sourced directly, rather than the file found in
$PATH. Example:
source /usr/local/bin/gvp-fish in
Where /usr/local/bin/gvp-fish is wherever you installed the fish script.