Note: untested.

• The -i.bak switch says "edit the input files in place, making backup files for each with a .bak extension".
• The -l switch says "do automatic line-end processing".
• The -p switch says "iterate over each line". Well, it does a bit more than that; see perldoc:perlrun for more.
• The $. special variable holds the input line number (like NR in awk).

--
F o x t r o t U n i f o r m
Found a typo in this node? /msg me
The hell with paco, vote for Erudil!

Unfortunately, when using <> (as -p does), $. is not reset after the close of each file. However, there is an example in the perlfunc:eof documentation of how to get around this (basically, you just have to do an explicit test of eof, then close the filehandle when it is found). The example is easily modified to fit this problem:

#!/usr/bin/perl -i.bak

while (<>) {
  s/^(N\d+ )?/N$. /;
}
continue {
  print;
  close ARGV if eof;
}
[download]

-- Mike

--
just,my${.02}

There's only a nasty caveat about $. on ARGV: it is not reset for each file, so it seems neccessary to "recode" the behaviour of <> in order to make this work as intended.

--
http://fruiture.de

#!/usr/bin/perl -w
use strict;

open(OLDF,"file.txt") || die $!;
open(NEWF,">newfile.txt") || die $!;

my $line=1;
while (<OLDF>) {
    s/^\s*(N\d+)?\s*/N$line /;
    print NEWF;
    $line++;
}
close(OLDF);
close(NEWF);
[download]

cLive ;-)

--
seek(JOB,$$LA,0);

How about something simple like: #!perl $myfile="c:/myfile.txt"; open MYFILE, $myfile or die "Cannot open $myfile for read :$!"; while (<MYFILE>) { print "N1 $. $_"; } while (<MYFILE>) { print "N $. $_"; }

OOPS My Bad- the above post shoulda been:
#!perl 
$myfile="c:/myfile.txt"; 
open MYFILE, $myfile or die "Cannot open $myfile for read :$!"; 

while (<MYFILE>)
{
  print "N1 $. $_"; 
}
[download]