From: mascheck@in-ulm.de (Sven Mascheck)
Subject: [TUHS] History of #! interpretation in Unix
Date: Sun, 16 Jan 2011 20:19:42 +0100 [thread overview]
Message-ID: <20110116191942.GA26424@lisa.in-ulm.de> (raw)
In-Reply-To: <20110116171715.GD3374@mercury.ccil.org>
John Cowan wrote:
> Sven Mascheck scripsit:
>
> > As you mention "shebangs began .. as csh-only hack":
> > I still wonder if one may call the BSD csh-hack as origin,
> > because #! might have been developed independently at Bell Labs.
>
> No, that would be too much of a coincidence to choose exactly the
> same characters. There has to be a single point of origin, from
> which it spread by stimulus diffusion (you hear there are telescopes,
> you know they use lenses, you build your own telescope).
This doesn't sound obligatory to me (I know it's academic).
DMR might have known the csh-hack (and if a comment character is
implemented anywhere, here csh, then it's obvious to use it for #!)
> > I thought sh-like shells in general try to interprete scripts themselves
> > upon an ENOEXEC. Do you know certain shells which actually call "/bin/sh"?
>
> Yes, seemingly bash does that too. Bogus.
How'd you get the impression? I can't verify this.
bash-1.05:execute_cmd.c executed the commands itself, in a subshell,
" [ errno == ENOEXEC ]
/* This file is executable.
If it begins with #!, then help out people with losing
operating systems. Otherwise, check to see if it is a binary
file by seeing if the first line (or upto 30 characters) are in
the ASCII set. Execute the contents as shell commands. */ "
and this hasn't been changed (except length or return status)
until the current release.
Perhaps you had another shell in mind? I believe a shell should
try to execute commands itself instead of calling any other shell.
(That's the only way how executing on in POSIX shell is possible, BTW,
because neither #! nor paths are standardized).
next prev parent reply other threads:[~2011-01-16 19:19 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-16 8:43 Warren Toomey
2011-01-16 9:55 ` John Cowan
2011-01-16 13:20 ` Sven Mascheck
2011-01-16 17:17 ` John Cowan
2011-01-16 19:19 ` Sven Mascheck [this message]
2011-01-16 20:17 ` John Cowan
2011-01-16 20:42 ` Larry McVoy
2011-01-16 21:08 ` Sven Mascheck
2011-01-16 21:37 ` John Cowan
2011-01-17 16:35 ` Warner Losh
2011-01-17 20:47 ` John Cowan
2011-01-17 10:09 ` Tim Bradshaw
2011-01-16 10:53 ` Wilko Bulte
2011-01-17 16:25 ` Warner Losh
2011-01-17 19:02 ` Jeremy C. Reed
2011-01-17 20:51 ` John Cowan
2011-01-17 22:41 ` Jeremy C. Reed
2011-01-17 20:58 ` Sven Mascheck
2011-01-19 4:10 ` Cyrille Lefevre
2011-01-19 20:35 ` Sven Mascheck
2011-01-20 4:09 ` Cyrille Lefevre
2011-01-28 19:38 ` Jeremy C. Reed
2011-01-30 15:05 ` Sven Mascheck
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20110116191942.GA26424@lisa.in-ulm.de \
--to=mascheck@in-ulm.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).