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From: maart@cs.vu.nl (Maarten Litmaath)
Newsgroups: comp.unix.wizards
Subject: Re: exec() with executable shell scripts
Keywords: exec() sh
Message-ID: <2351@solo11.cs.vu.nl>
Date: 22 Apr 89 03:04:54 GMT
References: <647@mqcomp.oz>
Organization: V.U. Informatica, Amsterdam, the Netherlands
Lines: 28

martin@mqcomp.oz (Martin Foord) writes:
\Everytime I seem to exec() a shell script that is executable I have problems
\(execepting if I use execlp() or execvp()).

The shell script doesn't start with the magic number #! or your kernel
doesn't recognize it, hence you get ENOEXEC ("Exec format error"), as you
would have known, had you put a call to perror() in your C program.
On the other hand, after having received an exec format error EXECVP()
decides the file must be a shell script, and executes /bin/sh with the file
as first argument. Hence execvp() works.

\...
\	execv("/bin/true",args);
\	printf("Can't execute process\n");

Thanks a lot for that *VERY* helpful error message! :-(
Instead do:

	perror("/bin/true");

If you are a Real Programmer, add:

	*(char *) -1 = 0xDEAD;

and read the hexdump with breakfast! :-)
-- 
 "If it isn't aesthetically pleasing, |Maarten Litmaath @ VU Amsterdam:
  it's probably wrong." (jim@bilpin). |maart@cs.vu.nl, mcvax!botter!maart