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Re: [bug-gawk] How to test if a variable is uninitialized or is just a v
From: |
Davide Brini |
Subject: |
Re: [bug-gawk] How to test if a variable is uninitialized or is just a variable that happens to be an empty string? |
Date: |
Tue, 09 Oct 2012 09:53:40 +0200 |
(sorry for top-posting)
Given awk's definition of "uninitialized variable", I think this could work:
if ((var == 0) && (var == "")) { print "uninitialized" }
Peng Yu <address@hidden> wrote:
Hi,
I'm not able to find a function to test if a variable is uninitialized
or is just a variable that happens to be an empty string in the
manual. Is there such a function in awk? Thanks!
~/linux/test/awk/lang/variable/undefined$ cat main.sh
#!/usr/bin/env bash
echo | awk 'BEGIN{print "^" x "$"}'
echo | awk 'BEGIN{if(x=="") { print "Hello World!" }}'
echo | awk 'BEGIN{x=""; if(x=="") { print "Hello World!" }}'
--
Regards,
Peng