Search and replace

kulua has asked for the wisdom of the Perl Monks concerning the following question:

I want to replace below string

input bist_g6bb_prn_clk_bistctlr;

output bist_g6bb_prn_clk_bistctlr;

and then change the output bist_g6bb_prn_clk_bistctlr; string to

assign vif.bist_g6bb_prn_clk_bistctlr = bist_g6bb_prn_clk_bistctlr;


use strict;
use warnings;
use autodie;

my $data = <<'EOD';

input  bist_g6bb_prn_clk_m;
EOD

open my $fh, '<', \$data;

while (my $line = <$fh>) {
    $line =~ s/input .*clk/output .*clk/g;
    print $line;
    }

close $fh;
[download]

I am new to perl, Can you point me my mistake ?

Comment on Search and replace Download Code

Replies are listed 'Best First'.
Re: Search and replace by hippo (Archbishop) on May 23, 2021 at 13:46 UTC
`$line =~ s/input .clk/output .clk/g;` The first part of `s///` is a regular expression but the second part is a string. It is essentially `s/REGEX/STRING/`. Since (in the first part of your task, which is the only part your code attempts to address) there are no complications, you can ignore the rest of the pattern and just do this: `$line =~ s/input/output/;` [download] That should get you farther along. For the general case you would need to use capture groups. 🦛	[reply] [d/l] [select]
Re^2: Search and replace by kulua (Initiate) on May 23, 2021 at 15:39 UTC
Hi Hippo , I want to change the string to output when the string clk matches not the input to output Can you provide me good tutorial for reg expression ?	[reply]
Re^3: Search and replace by hippo (Archbishop) on May 23, 2021 at 16:10 UTC
You could try Regular Expressions Tutorial, the Basics (for BEGINNERS) which is listed on our Tutorials page under the Pattern Matching, Regular Expressions, and Parsing section. There's also the official tutorial at perlretut. Enjoy. 🦛	[reply]
Re^3: Search and replace by tybalt89 (Monsignor) on May 23, 2021 at 16:09 UTC
`$line =~ s/input(?= .*clk)/output/g;` [download] Untested since no test cases were provided.	[reply] [d/l]
Re: Search and replace by 1nickt (Canon) on May 23, 2021 at 13:35 UTC
Please answer this question: have you read and studied the examples in perlrequick? There is a section entitled exactly "Search and replace". The way forward always starts with a minimal test.	[reply]