Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!seismo!elsie!ncifcrf!randy
From: randy@ncifcrf.UUCP (The Computer Grue)
Newsgroups: comp.unix.wizards
Subject: Re: #! magic number
Message-ID: <136@ncifcrf.UUCP>
Date: Mon, 29-Jun-87 09:33:03 EDT
Article-I.D.: ncifcrf.136
Posted: Mon Jun 29 09:33:03 1987
Date-Received: Wed, 1-Jul-87 01:56:43 EDT
References: <a7879@brl-adm.ARPA> > <2211@bunker.UUCP> <1097@mtune.ATT.COM> <1895@vdsvax.steinmetz.UUCP>
Organization: NCI Supercomputer Center, Frederick, MD
Lines: 51
Summary: Spaces seem to cause a problem

In article <1895@vdsvax.steinmetz.UUCP>, barnett@vdsvax.steinmetz.UUCP (Bruce G Barnett) writes:
> Yes, I did try #!/bin/awk -f
> 
> I STILL get the "bail" error:
> Exhibit A, Ultrix 1.2:
> 
> csh >cat t.awk
> #!/bin/awk -f 
>   BEGIN { print "Begin"}
>   { 
>   print;
>   }
>   END { print "End"}
> csh> awk -f t.awk </dev/null
> Begin
> End
> csh> t.awk
> awk: syntax error near line 1
> awk: bailing out near line 1  
> 

    You are not going to f**king believe this.  I got curious enough
  about your question to start fiddling (I use several awk 'shell
  scripts' and they work fine for me) and I think I figured out what
  the problem is.  You have a space (that's right, hex 0x20, char ' ',
  whatever) immediately after your '-f'.  This seems to be a problem
  because the kernel is passing '-f ' (as opposed to '-f', which is what the
  shell would pass it) to awk as it's first argument and it doesn't
  seem to know how to deal with a space immediately after a flag.
  Since the argument parsing is done in the kernel for the 'interpeter
  line' of shell scripts and in the shell for straight command line
  arguments, awk's getting a little hosed when called through the
  'exec' mechanism.

    I confirmed this hypothesis two ways.  First, I deleted the space
  at the end of the first line and Bruce's program runs fine.  That is to
  say, the program:
-------------------------
#!/bin/awk -f
  BEGIN { print "Begin"}
  { 
  print;
  }
  END { print "End"}
---------------------

  works fine for me (check it; no space) where the original program
  does not.  Second, I invoked "awk '-f ' awk.inp" and reproduced the
  syntax error message.

    Weird.  I'm not sure whether I'd call this a bug in the kernel
  processing of the '#!' magic number, or whether awk should be able
  to handle '-f ' as an argument.  Bad synergy.

					-- Randy Smith

-- 
  Randy Smith    @	NCI Supercomputer Facility
  c/o PRI, Inc.		
  PO Box B, Bldng. 430  Phone: (301) 698-5660                  
  Frederick, MD 21701  	Uucp: ...!seismo!elsie!ncifcrf!randy