gc is written in gawk. Of course, gawk can't do all the stuff on its own - it's not python - and relies one some standard UNIX commands.
gawk --version). This is the script interpreter and other awk dialects will not work.
rlwrap ./gcinstead of
If you have a debian based distribution
sudo apt-get install gawk socat lynx
installs the required packages.
Some more functionality is in external scripts but these come in gc's tar archive (see below).
gc's comes without a proper Linux / UNIX installation. The reason is simple: I want to make it totally easy for everyone to try gc wihtout touching the system installation. gc comes with a tar archive that unpacks into the directory gc-version.
gc needs to find it's supplemental scripts gmi2text and md2text. If you start gc with a path other than /usr/bin/ or /usr/local/bin then gc expects the scripts to be in the same directory as gc. If instead gc is in one of the system's directories then the script must be copied to /usr/lib/gc or /usr/local/lib/gc respectively. Alternatively you might set the script path with the -l option.
Effectively this means that for a simple test installation and start
tar -xzvf gc-version.tar.gz cd gc-version ./gc
is enough. After you have checked what it is you can still think about where to put the scripts.
If you didn't copy gc from its untarred directory to somewhere else, all you need to do is to remove that directory. If you installed some off the prerequisites and you want to remove them too then
sudo apt-get purge package-names
will do it.