Hi guys,
I'm doing a script to search through a lot of files and doing some replacements.
It is a lot of different replacements that has to be done so I list them in a
.txt
instruction file in two columns representing the strings to be matched and
replaced
and the new text.
A problem arise when doing some more complex substitution, wanting to keep
certain
parts of a string while replacing others. To be specific in this case I want to
remove the '' surrounding a string. The string between '' will change.
The problem comes from that I want to use the \1 (or $1) variable but since the
substitution command looks like
$line=~ s/$subst_from/$subst_to/ig;
and the $1 is incorporated into the $subst_to variable it is being populated
when
the replecement string is assinged to $subst_to.
How can I keep the substitution command as general as I have it, always taking
the
same to variables but still making use of the $1,...,$9 feature of Perl?
I post you a test-program which shows my problem.
List.\1 being printed after 'Result:' is the problem.
It's developed in an cygwin-environment and executes using the command
perl PerlSubstituteProblem.pl
The printouts looks like this when I run it:
Script started.
subst_to: List.\1
'' should be removed in List.'123_KeepThis_123'
$1_1: 123_KeepThis_123
$1_2: 123_KeepThis_123
Result:
'' should be removed in List.\1
Same thing but non-general s//:
'' should be removed in List.123_KeepThis_123
Changed in 1 places
________Program_______________
#!/usr/local/bin/perl
use strict;
use strict 'refs';
$|=1; #Flush ON
print "Script started.\n";
my($nr_of_changes,$line,$line_copy, $subst_from,$subst_to)=0;
$subst_from="List\\.'(\\w*)'";
$subst_to="List.\\1";
print "subst_to: $subst_to \n";
$line="'' should be removed in List.'123_KeepThis_123' \n";
print "$line";
if($line =~/$subst_from/i)
{
$line_copy=$line;
print "\$1_1: $1 \n";
$nr_of_changes++;
$line=~ s/$subst_from/$subst_to/ig;
print "\$1_2: $1 \n";
print "Result: \n";
print "$line";
print "Same thing but non-general s//: \n";
$line_copy=~ s/$subst_from/List.\1/ig;
print "$line_copy";
}
print"Changed in $nr_of_changes places\n";
exit(0);
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