Re: /0/0 in gawk

[Aharon Robbins]

> To: address@hidden
> From: Dan Jacobson <address@hidden>
> Subject: /0/0 in gawk
> Date: 08 Jan 2002 19:52:16 +0800
>
> OK, I forgot to quote "/dev/stdout" [GNU Awk 3.1.0]:
>
> $ awk 'BEGIN{print "b" /dev/stdout}'
> awk: cmd. line:1: fatal: division by zero attempted
> $ awk 'BEGIN{print "b"> /dev/stdout}'
> $ ls -l 0
> -rw-r--r--    1 jidanni  jidanni         2 01  8 19:55 0
>
> OK, my question is why can it make a 0 out of /../.. when making a
> filename, but not otherwise?  Shame, shame.  /../.. must be "new
> math".
>
> ok, I get it. the first one is "b"/0/0, ["b"==0], and the second one
> is 0/0/, but what is /0/0?
> At least the second one is a bug?

There are no bugs here.  The first is the equivalent of 0 / 0 / 0.

The value "b" becomes 0.  The variables `dev' and `stdout' are
automatically initialized to zero.  In the case of the
redirection, it's parsed as

        print "b" > ( (/dev/) stdout )

The `/dev/' is the same as ($0 ~ /dev/), which in this case is zero,
concatenated with the empty string value of the variable `stdout'.
This leads to a filename of "0".

This is explained in the gawk documentation.

Arnold