Ultrix 4.1 /bin/csh / awk bug?

[Frank Wortner]

In article <V4K1Y3Z at dri.com>, braun at dri.com (Kral) writes:

> Can someone tell me if this is a known bug ...   It seems that either csh
> or awk is barfing on the '#!' majik number.

Everything is working as documented.  Here's a quote from the execve(2)
manual page:

          An interpreter file begins with a line of the form ``#! inter-
          preter''.  When an interpreter file is executed the system exe-
          cutes the specified interpreter, giving it the name of the origi-
          nally executed file as an argument, shifting over the rest of the
          original arguments.

So, if we take your example:

#! /bin/awk

{
	print "This is a test."
}
#

and place it in the file test.awk, here is what happens:

	The kernel gets an exec-something-or-other system call with
	test.awk as an argument.

	The loader figures out that this is an interpreter file.

	The call is rearranged so that it looks like this:

	/bin/awk test.awk

	Awk assumes that its first and only argument is a program.

	The words "test.awk" do not constitute a valid awk program.

	OOPS!  Syntax error!

If you want awk to execute your program try making one small
change:

#! /bin/awk -f

instead of

#! /bin/awk

This way, when the loader calls /bin/awk, the result will be:

	/bin/awk -f test.awk

and things will work the way you expect.

Hope this clears things up a bit.  Have fun!


					Frank