Date: Fri, 28 Oct 2016 17:02:02 +0100 From: Arthur Chance <freebsd@qeng-ho.org> To: Tim Daneliuk <tundra@tundraware.com>, FreeBSD-Questions <freebsd-questions@freebsd.org> Subject: Re: Interesting $0 Problem Message-ID: <06dacace-e46a-9437-4fa6-ab4d1ea9a2a0@qeng-ho.org> In-Reply-To: <5a4f0424-cdfa-bd44-9de2-b4860d121584@tundraware.com> References: <b859f7a3-51d1-06f4-e793-332edd212068@tundraware.com> <516bc76f-f14c-e9a5-a246-2e915a5369ce@qeng-ho.org> <5a4f0424-cdfa-bd44-9de2-b4860d121584@tundraware.com>
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On 28/10/2016 15:40, Tim Daneliuk wrote: > On 10/28/2016 03:34 AM, Arthur Chance wrote: > <SNIP> > >> >> >> Prepending a dash to a login shell has been standard behaviour since the >> BSD days at least. I think it was in version 6 of the original Bell Labs >> Unix as well, but after three and a half decades my memories for such >> details are a bit hazy. Anyway, it's a standard marker. >> > > > Thanks to all who took the time to answer what turned out to be a really > stupid question on my part. It's odd that I've never run into this > in over 3 decades of working on *NIX ... > > So now, can someone perhaps answer a couple of other really dumb questions: > > When is it useful for a script to know it's running in a login context vs. > a child of the login shell? When you want to automatically fire up ssh-agent or X or screen/tmux, or any other program that only makes sense to start once per login. > Is there another way to determine if your current shell is the login shell? csh/tcsh sets the variable loginsh only in login shells. I don't believe sh does anything special. > This is more intellectual curiosity than anything ... Nothing wrong with intellectual curiosity. It's the people without it I have problems with. :-) -- Schrödinger's cat had 18 half lives.
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