CODEWITHSUNDEEP
perl
James
James

Reputation: 1490

Find replace across multiple lines in Perl?

Is there a way to replace instances of a string beginning with START and ending with END in a file, across multiple lines, in perl?

i.e. input:

good
START
bad
bad
END
good

Then find the range from START to END, and replace with 'replaced':

good
replaced
good

Thanks very much.

Upvotes: 0

Views: 101

Answers (3)

Praveen
Praveen

Reputation: 902

This is a simple Perl program which replaces the strings between START and END (Case insensitive) as shown in the below code:

#!/usr/bin/perl
    use strict;
    use warnings;
    my $InFile = $ARGV[0];
    my $document = do {
        local $/ = undef;
        open my $fh, "<", $InFile or die "Error: Could Not Open File $InFile: $!";
      <$fh>;
    };
    $document =~ s/\bSTART\b.*?\bEND\b/replaced/isg;
    print $document;

Upvotes: 0

mpapec
mpapec

Reputation: 50637

You can use flip-flop .. operator:

perl -pe '$_ = $i == 1 ? "replaced$/" : "" if $i = /START/ .. /END/' file

$i count lines from START to END, or it holds false value when outside start-end block.

Upvotes: 2

choroba
choroba

Reputation: 241748

Use a flag. Something like the following:

perl -ne '$inside = print "replaced\n" if /START/;
          print unless $inside;
          undef $inside if /END/' file

Upvotes: 2

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