How the perl converts LF into CRLF

[perladdict]

Hi Monks, I have a file on unix os,as i know that in unix every line is padded with LF i,e,default.now i am sending the content of this file to some remote server which run on win os by using perl.In that scenario by which mechanism perl will converts LF to CRLF. Waiting for your saggation.

[sh1tn]

UNIX has '\n' end of line;
Windows family has '\r\n' instead;
Mac OS has '\r';
In perl you can convert (simulate dos2unix and unix2dos) like this:


# unix2dos:
# perl -i.org -pe 's/\n/\r\n/' filename 
# dos2unix:
# perl -i.org -pe 's/\r\n/\n/' filename

[ikegami]

Those won't work on a Windows box because binmode wasn't used.

[schnell18]

You are right. Below is the dos2unix equivalent works on Windows

#!/usr/bin/perl -w

use strict;
use File::Temp qw(tempfile);
use File::Copy;

dos_to_unix($ARGV[1]);

sub dos_to_unix {
    my($file) = @_;

    my($dst, $src);
    my (undef, $tmpfile) = tempfile();

    copy($file, $tmpfile)
      or die "Can't copy $file to $tmpfile due to: $!\n";
    open($dst, ">$file")
      or die "Can't open $file for write due to: $!\n";
    open($src, "<$tmpfile")
      or die "Can't open $tmpfile for read due to: $!\n";

    binmode($dst);
    while(<$src>) {
        chomp;
        print $dst "$_\n";
    }

    close($dst);
    close($src);
}

[derby]

How are you sending it? If you use Net::FTP in ascii mode, the translastion will be done auto-magically.

[perladdict]

Hi Derby, thanks for suggetion,i am using Net::cmd in my script,in which i included senddata(DATA) method.

[derby]

Hmmm ... never used Net::Cmd directly. For Net::FTP the translation is not done in the client but on the server side. What type of server are you connecting to? FTP? Home grown?

Update: That is for all ftp ... not just Net::FTP, the translation is done in the server.

[Joost]

How are you sending the file? Some mechanisms (like ASCII FTP transfers) translate line-ends automatically.

Anyway, check out binmode and the open pragma

[xdg]

If you don't want to do it manually, but want to understand how Perl does it, read perlport and perlio.

One simple option is to call binmode on the filehandle on the win32 machine to disable automatic CR/LF translation and then everything will stay with LF for line endings. (Note this will cause issues for UTF-8, so if you're worried about that, you will need to read about the various IO layers described in perlio.)

[jdtoronto]

Did you read the POD for the Net::cmd module? If you had you would find this:

datasend ( DATA )

    Send data to the remote server, converting LF to CRLF. Any line st
+arting with a '.' will be prefixed with another '.'. DATA may be an a
+rray or a reference to an array.

jdtoronto