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From: jiml@uwslh.slh.wisc.edu (James E. Leinweber)
Newsgroups: comp.unix.ultrix
Subject: Re: Awk strangeness or misunderstandings?
Keywords: awk
Message-ID: <1991May2.162303.10658@uwslh.slh.wisc.edu>
Date: 2 May 91 16:23:03 GMT
References: <115@janis.UUCP>
Organization: Wisconsin State Laboratory of Hygiene
Lines: 25

ericw@janis.UUCP (Eric Wedaa) writes:
>I've been having some troubles with awk under Ultrix 3.0 and 3.1. ...
>    awk '{system("date")}' test.file ...  produces NO output.

Under Ultrix 4.1 on a Vaxstation 3100 and 4.3BSD Unix on an 11/750, I get:
    (/usr/1/wbacti) sente$ awk 'END{print system("date")}' < /dev/null
    date
    (/usr/1/wbacti) sente$ nawk 'END{print system("date")}' < /dev/null
    Thu May  2 11:15:14 CDT 1991
    0

Consulting the documentation we have on the old and new awks, it appears
that the system() function was one of the 1985 additions.  Old awk evaluates
system("date") as a concatenation of an uninitialized variable named
"system" with a string "date".  Since concatenation is implicit and so
is variable initialization, this surprising behavior is required by the
language definition.  

The solution is to get a recent version of awk.  Upgrading to Ultrix
4.1 is one way; failing that I'd suggest getting the GNU awk clone
"gawk" from your nearest comp.sources archive or the FSF.

-- 
Jim Leinweber  (608)262-0736   State Lab. of Hygiene/U. of Wisconsin - Madison 
jiml@sente.slh.wisc.edu	       uunet!uwvax!uwslh!jiml        fax:(608)262-3257