novice needs help with file I/O

[awingnut]

I have the following partially written script:

#!/usr/bin/perl -w
#
# This script fixes the AWStats config file so the current IP address is
# included in the statistics
#

use strict;

my $awcfgfile = "awstats.conf";
my $awcfgdir = "/etc/awstats";
my $tmpcfgfile = "awstatsnew.conf";

open(FHIN,"< $awcfgdir/$awcfgfile") || die "Unable to open $awcfgfile for input:
 $!\n";
open(FHOUT,"> /tmp/$tmpcfgfile") || die "Unable to open /tmp/$tmpcfgfile for out
put: $!\n";

my $line="";
my $indx=0;
while (! undef ($line=readline(FHIN))) {
        print $line;
        if (($indx=index($line,"HostAliases"))>=0) {
                print "Found it!\n";
        }
        print FHOUT $line || die "Write error: $!";
}
close(FHOUT);
close(FHIN);

I am getting 3 errors when I run this:

Use of uninitialized value in print at /usr/local/bin/fixawconf.pl line 19, <FHIN> line 1.
Use of uninitialized value in index at /usr/local/bin/fixawconf.pl line 20, <FHIN> line 1.
Write error: Bad file descriptor at /usr/local/bin/fixawconf.pl line 23, <FHIN> line 1.

It seems that it doesn't like something about my file descriptor (FHIN) although it is '$line' that is the common element in the lines the error is complaining about. Can someone tell me what I am doing wrong? TIA.

 

[PaulTEG]

if (($indx==index($line,"HostAliases"))>=0) { is one error you're lookig at, a single = is assignment and always returns a true value.

also drop the spaces between filename and director
">/tmp/$tmpcfgfile" instead of "> /tmp/$tmpcfgfile"

HTH
--Paul

Paul
------------------------------------
Spend an hour a week on CPAN, helps cure all known programming ailments ;-)

 

[ishnid]

Assignment returns the value of whatever was being assigned, so it's not necessarily always a true value.

 

[awingnut]

Thanks for the replies. Removing the white space didn't change anything and indeed the docs say it shouldn't matter. As for the '=' vs. '==', I believe my single '=' is the correct syntax. I want the value returned set to '$indx' and then the value of '$indx' compared with '0'. If the substring is not found, 'index' is supposed to return -1 in which case the expression is false, as intended. Am I misunderstand the perl syntax?

 

[awingnut]

I may have figured out what is wrong but I don't know how to fix it. I think 'undef' is not being used as a unary logical operator but rather as a function. My variable is being 'undef'ed. What is the syntax for testing for an 'undef' variable in my 'while' loop? TIA.

 

[raklet]

Use of uninitialized value means that the variable is empty and no information was passed to it.

Bad file descriptor indicates a problem with the path to the file or the file does not exist.

You guess about $line being the problem is correct. If no value is assigned to $line during "readline(FHIN)" then everything else after that point that depends on $line will fail also.

 

[awingnut]

Got it! I was right, my 'while' test was not testing for 'undef' it was 'undef'ing the variable. Since 'defined' is NOT a funtion, I changed my test from '! undef' to 'defined' and it works. Thanks anyway.

 

[PaulTEG]

== is for use as numeric comparison
eq is for string operations

= is an assignment, error mine previously, thanks ishnid, NOT the correct syntax

--Paul

Paul
------------------------------------
Spend an hour a week on CPAN, helps cure all known programming ailments ;-)