Edit( filename )
Edit
starts an editor with the file whose filename is given by the
string filename, and reads the file back into GAP when you exit the
editor again. You should set the GAP variable EDITOR
to the name of
the editor that you usually use, e.g., /usr/ucb/vi
. This can for
example be done in your .gaprc
file (see the sections on operating
system dependent features in chapter Getting and Installing GAP).
GAP 3.4.4