The GECOS format (aka GCOS) has been well defined for several
DECADES (well more than 25 years).  If your mail tool doesn't
handle it right, then I gotta think the problem lies there.

I've had unix accounts with GCOS entries for an excessively
long time.  Never have I had a problem with MUA's (or MTAs)
"leaking" extra info.

Quoting Andrew Brown (atatat@atatdot.net):
> >Are these annoying anyone else :) ?
> >
> >Whenever a user  edits information with chfn, their
> >entries in /etc/passwd change from
> >
> >rasputin:*:<UID>:<GID>:Rasputin:<HOMEDIR>:<SHELL>
> >
> >to:
> >
> >rasputin:*:<UID>:<GID>:Rasputin,,,:<HOMEDIR>:<SHELL>
> >
> >(if you leave your phone nunmber, etc blank)
> >
> >This 'trailing comma' pattern looks a bit rough in mails, etc.
> >and if you want to fix this, you need root.
> 
> afaik, those commas have been there for a looong time.  it might be
> easier to fix the mail client that's getting it wrong.  if it knows to
> look up gecos, it ought to know to look for commas in it.
> 
> -- 
> |-----< "CODE WARRIOR" >-----|
> codewarrior@daemon.org             * "ah!  i see you have the internet
> twofsonet@graffiti.com (Andrew Brown)                that goes *ping*!"
> andrew@crossbar.com       * "information is power -- share the wealth."