A more robust way to do this would be something like this,
that uses a reusable generic function for the actual replacements.
Especially if your template string is going to be dynamic.

#!/usr/local/bin/perl
use strict; 

my $filter      = q{user ([^\s]+) has ([^\n\r]+)$};

my $log_string  = q{user bob has logged on};

my $template    = q{user $1 has accessed the system and is $2}; 
      

if ( $log_string =~ /$filter/ )
{
    # would be better to use something else rather  
    # than '$1' as a replacement mark
    my %vars = 
    (
        '$1' => $1,
        '$2' => $2,
    );

    my $t = interpolate( $template, \%vars );

    print qq{LINE: [$t]\n};
}


sub interpolate
{
    my ( $text, $vars ) = @_; 

    study $text;

    $text =~ s/\Q$_\E/$vars->{$_}/g for ( keys %{$vars} );

    return $text;

} # END interpolate

[download]
Wonko

In reply to Re: How can I use $1 in an assigned string by Wonko the sane
in thread How can I use $1 in an assigned string by kitsonrp

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