making one single line - perl

Question

keyword harry /
sally/
tally/
want that whenever the string matches with keyword it should also look for "/" character.This signifies continuation of line
Then I want output as
keyword harry sally tally
==========================
My current code:
#!/usr/bin/perl
open (file2, "trial.txt");
$keyword_1 = keyword;
foreach $line1 (<file2>) {
s/^\s+|\s+$//g;
if ($line1 =~ $keyword_1) {
$line2 =~ (s/$\//g, $line1) ;
print " $line2 " ;
}
}

Answer 1

If the ===== lines in your question are supposed to be in the output, then use
#! /usr/bin/env perl
use strict;
use warnings;
*ARGV = *DATA; # for demo only; delete
sub print_line {
my($line) = #_;
$line =~ s/\n$//; # / fix Stack Overflow highlighting
print $line, "\n",
"=" x (length($line) + 1), "\n";
}
my $line = "";
while (<>) {
$line .= $line =~ /^$|[ \t]$/ ? $_ : " $_";
if ($line !~ s!/\n$!!) { # / ditto
print_line $line;
$line = "";
}
}
print_line $line if length $line;
__DATA__
keyword jim-bob
keyword harry /
sally/
tally/
Output:
keyword jim-bob
================
keyword harry sally tally
==========================

Answer 2

You did not specify what to do with the lines that do not contain the keyword. You might use this code as an inspiration, though:
#!/usr/bin/perl
use warnings;
use strict;
my $on_keyword_line;
while (<>) {
if (/keyword/ or $on_keyword_line) {
chomp;
if (m{/$}) {
chop;
$on_keyword_line = 1;
} else {
$on_keyword_line = 0;
}
print;
} else {
$on_keyword_line = 0;
print "\n";
}
}

Answer 3

A redo is useful when dealing with concatenating continuation lines.
my $line;
while ( defined( $line = <DATA> )) {
chomp $line;
if ( $line =~ s{/\s*$}{ } ) {
$line .= <DATA>;
redo unless eof(DATA);
}
$line =~ s{/}{};
print "$line\n";
}
__DATA__
keyword harry /
sally/
tally/
and
done!!!
$ ./test.pl
keyword harry sally tally and
done!!!

Answer 4

I think you need to simply concatenate all lines that end in a slash, regardless of the keyword.
I suggest this code.
Updated to account for the OP's comment that continuation lines are terminated by backslashes.
while (<>) {
s|\\\s*\z||;
print;
}