Most public-domain (and even commercial) software comes with bugs, and the speed with which such bugs are detected and removed depends to a large degree on the willingness of the user community to report these to us in a useful manner. When your car breaks down, simply telling the mechanic that it doesn't work will hardly speed up the repair or cut back costs! Therefore, we ask that if you detect a bug, first make sure that it in fact is a bug and not a user error. Then, send us email about the problem. Be sure to include all the information necessary for us to recreate the situation in which the bug occurred. This will include the full command line used and, if possible, the data file used by the program. Send the bug-reports to gmt@soest.hawaii.edu. We will try to fix bugs as soon as our schedules permit and inform users about the bug and availability of updated code (See Appendix D).
Two electronic mailing lists are available to which users may subscribe. gmtgroup@soest.hawaii.edu and is primarily a way for us to notify the users when bugs have been fixed or when new updates have been installed in the ftp directory (See Appendix D). We also maintain another list (gmthelp@soest.hawaii.edu) which interested users may subscribe to. It basically provides a forum for GMT users to exchange ideas and ask questions about GMT usage, installation and portability, etc. Please use this utility rather than sending questions directly to gmt@soest.hawaii.edu. We hope you appreciate that we simply do not have time to be everybody's personal GMT tutor.
The electronic mailing lists are maintained automatically by a program. To subscribe to one or both of the lists, send a message to listserver@soest.hawaii.edu containing the command(s):
subscribe gmtgroup 
your full name, not email address
subscribe gmthelp your full name, not email address
(Do not type the angular brackets ). You may also
register electronically via the GMT home web
page7.1. For information
on what commands you may send, send a message containing
the word help. You must interact with the listserver to be
added to or removed from the mailing lists! We strongly recommend that you
at least subscribe to gmtgroup since this is how we can notify
you of future updates and bug-fixes. Most new users will
also benefit from having the other forum (gmthelp) as they
struggle to realign their sense of logic with that of GMT.
While anybody may post messages to gmthelp, access to gmtgroup
is restricted to minimize net traffic. Any message sent to
gmtgroup will be intercepted by the GMT manager who will
determine if the message is important enough to cause thousands
of mailtools to go BEEP. Communication with other GMT users
should go via gmthelp. Finally, all GMT information is provided
online at the main GMT home page in Hawaii, i.e.,
www.soest.hawaii.edu/gmt. Changes to GMT will also be posted
on this page. The main GMT page has links to the official
GMT ftp sites around the world.