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From: rees@dabo.ifs.umich.edu (Jim Rees)
Newsgroups: comp.sys.apollo
Subject: Re: start_sh ( was Re: start_csh )
Message-ID: <1990Jun9.022616.21538@terminator.cc.umich.edu>
Date: 9 Jun 90 02:26:16 GMT
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start_* are all the same program.  What it does, approximately, is strip off
the 'start_' on arg 0 then look in /bin for a program by that name.  Then it
sets $SHELL to /bin/(shellname) and execs the shell, with arg 0 set to
-(shellname).

The shells look at arg0, and if it starts with '-', they run their
respective startup file (.profile, .login, etc).

So the main function of start_foo is to set arg0 to -foo so you get your
login startup file executed.

It's not needed if you log in the normal (Unix) way, with /bin/login, which
sets arg0 for you.  It's mostly useful if your login shell was started by
something like the DM that doesn't do this.