perl -pi -e 'm{^/index} and s/$/%/' file
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use Tie::File;

tie my @fl, 'Tie::File', "filename.here"
  or die "ack: $!";

for(@fl) {
  m{^/index} and s/$/%/;
}
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open(my $in_fh,  '<', "input.filename")  or die "ack: $!";
open(my $out_fh, '>', "output.filename") or die "ack: $!";

while(<$in_fh>) {
  m{^/index} and $_ .= "%";
  print {$out_fh} $_;
}

close $in_fh;
close $out_fh;

rename( "output.filename", "input.filename" )
  or die "ack: $!";
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_________
broquaint

update: have fixed code to DTRT, thanks to delirium

Broquaint,

All these are going to add the percent sign after $/, no?

I'd use -l from the command line (e.g., Abigail's solution), or something like

$_=~s/$/%/;

replacing the

$_.='%';

(Update: autochomp will take care of this in Tie::File)

    perl -wpi -le '$_ .= "%" if m!^/index!' file
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Abigail

Sunadmn, you're very kind,

The file is a bibliography file some of whose lines start /index while many others also have a / at the beginning.

My problem is to add a %-sign at the end of the /index lines.

I know that it might be simply done in Perl, I just have such little experience yet that trying to piece it together in the on-line manual has been rather a lengthy process.

Is this enough detail ?

TIA

sativa

I believe that my fellow monks should have given you enough to work with here if not please let us know.