Re: find a substring using regex and then replace it

There are 2 problems there: you are using bge1 as a bareword and you are escaping the dollars in the regex thus preventing them from doing what you want. Here's the working version:

#!/usr/bin/env perl 
use strict;
use warnings;

my $Interface = 'bge1';
$Interface =~ s/[0-9]$/:$&/;
print $Interface . "\n";
[download]

which outputs "bge:1".

Comment on Re: find a substring using regex and then replace it Download Code

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Re^2: find a substring using regex and then replace it by johngg (Canon) on May 02, 2016 at 16:08 UTC
It's unlikely but not beyond the realms of possibility to have more than ten interfaces so it would be safer to match for one or more (`+`) digits at the end of the string. This gives the wrong result:- `$ perl -Mstrict -Mwarnings -E ' my $interface = q{bge12}; $interface =~ s{[0-9]$}{:$&}; say $interface;' bge1:2 $` [download] This corrects the problem. I also prefer to use the `\d` special escape for digits and a look-ahead to save having to mention what was matched in the replacement part:- `$ perl -Mstrict -Mwarnings -E ' my $interface = q{bge12}; $interface =~ s{(?=\d+$)}{:}; say $interface;' bge:12 $` [download] I hope this is of interest. Cheers, JohnGG	[reply] [d/l] [select]

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Re^2: find a substring using regex and then replace it
by johngg (Canon) on May 02, 2016 at 16:08 UTC

It's unlikely but not beyond the realms of possibility to have more than ten interfaces so it would be safer to match for one or more (+) digits at the end of the string. This gives the wrong result:-

 $ perl -Mstrict -Mwarnings -E '
my $interface = q{bge12};
$interface =~ s{[0-9]$}{:$&};
say $interface;'
bge1:2
$
[download]

This corrects the problem. I also prefer to use the \d special escape for digits and a look-ahead to save having to mention what was matched in the replacement part:-

 $ perl -Mstrict -Mwarnings -E '
my $interface = q{bge12};
$interface =~ s{(?=\d+$)}{:};
say $interface;'
bge:12
$
[download]

I hope this is of interest.

Cheers,

JohnGG

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