Reading lines from files Perl

jack.barnes · 04-14-2011, 03:51 AM

Hi All,

The code below is currently reading any line that does not meet my criteria (which is working fine). Instead of printing the line that is incorrect (which it currently does) I wish for it to print the line above it from the file instead of the actual line (the line above has the name which is valuable to the user)

Code:

use Getopt::Long;
use warnings;
use strict;

open my $input, "mirror_status_data";

my $broken_line = '';
my $all_ok=1;

while (<$input>){

    if ( $_ =~ /V Status/ && $_ !~ /available(\/syncd)?$/ ){
	$broken_line = $_;
	$all_ok=0;
	print "badline: $broken_line";
    }   
};

if ($all_ok==0) {
    print "CRITICAL \n";
   # print "badline: $broken_line";
}
else{
    print "OK \n";
}

close $input;

Any Suggestions?

brownie_cookie · 04-14-2011, 04:19 AM

i'm not familiar with Perl so don't be mad if it doesnt work, but sometimes i need something like you are using (but then in another programming language) and then i do "-1"
i geuss you got to do something like:

Code:

while (<$input>){

    if ( $_ =~ /V Status/ && $_ !~ /available(\/syncd)?$/ ){
	$broken_line = $_ -1;
	$all_ok=0;
	print "badline: $broken_line";
    }   
};

I really don't know if that's possible
or the thing that you put in $broken_line is that a word or a number ?

bsat · 04-15-2011, 03:14 AM

I don't know a perl specific solution but here is something that might work

Code:

while (<$input>){


    if ( $_ =~ /V Status/ && $_ !~ /available(\/syncd)?$/ ){
	$broken_line = $_;
	$all_ok=0;
	print "badline: $prev_line";
    }   
$prev_line = $_
}

grail · 04-15-2011, 04:05 AM

There is probably a Perl-centric solution, but brownie's idea and bsat's solution is the way I would go.
Basically you store the previous line on each iteration of the file and when your if is true you print the last stored value.