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I am trying to assign an iutput of perl command to a variable . but getting an erro. below is the pelr command.

Posted on 2011-03-25
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Last Modified: 2013-11-13

#!/usr/sbin/perl
value=`perl -ne '{/zone "rajat.com" {/ and print "$."}' /etc/postfix/test | head -1`
print  $value;

When i run this script i get the below error
Error-
Can't modify constant item in scalar assignment at /usr/local/sbin/test25 line 78, near "print"
syntax error at /usr/local/sbin/test25 line 78, near "print"
Execution of /usr/local/sbin/test25 aborted due to compilation errors.
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Question by:pehalwaan
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6 Comments
 
LVL 26

Expert Comment

by:wilcoxon
ID: 35217937
It looks like you're missing a semi-colon at the end of the assignment line.
#!/usr/sbin/perl
value=`perl -ne '{/zone "rajat.com" {/ and print "$."}' /etc/postfix/test | head -1`;
print  $value;

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LVL 26

Expert Comment

by:wilcoxon
ID: 35217982
Rather than having a perl script call a perl one-liner, why not do this?  It will give the same output.
#!/usr/sbin/perl

open IN, '/etc/postfix/test' or die "could not open /etc/postfix/text: $!";
while (<IN>) {
    next unless /zone "rajat.com" {/;
    print $.;
    last;
}
close IN;

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Author Comment

by:pehalwaan
ID: 35218829
I want to use one liner only and want to store the output of that one liner into the variable so that i can use that value to start a loop.
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LVL 26

Accepted Solution

by:
wilcoxon earned 500 total points
ID: 35219245
I did notice both your original code and my first code have a typo - it should be "$value=..." in the first line.

Calling a one-liner will work but will be much less efficient.  If you want to use the return to start a loop, you can do...
#!/usr/sbin/perl

# you should always use strict and warnings...
use strict;
use warnings;

my $start;
open IN, '/etc/postfix/test' or die "could not open /etc/postfix/text: $!";
while (<IN>) {
    next unless /zone "rajat.com" {/;
    $start = $.;
    last;
}
close IN;

for ($start..999) {
}

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LVL 26

Expert Comment

by:wilcoxon
ID: 35219251
So, if you really want to use a one-liner, this is the further corrected code...
#!/usr/sbin/perl
$value=`perl -ne '{/zone "rajat.com" {/ and print "$."}' /etc/postfix/test | head -1`;
print  $value;

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Author Closing Comment

by:pehalwaan
ID: 35219324
Thanks a lot.
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