perl, cpio, and pipe

momo33 has asked for the wisdom of the Perl Monks concerning the following question:

Hello Monks

I have a problem handling an archive from within Perl (under Windows 7)

I have an archive and want to add a few files. The files to add are in a subdir which resides in $archivedir. The list of files is in @filelist (path relative to $archivedir). When I run it it creates arch.cpio.new but it remains empty and gives messages that it cannot find the files to add:

/tttest/cpio: test/1: Cannot stat: No such file or directory
/tttest/cpio: test/2: Cannot stat: No such file or directory
/tttest/cpio: test/3: Cannot stat: No such file or directory
1 block
[download]

The files are there...
Any suggestions?
Thank you.

My code:
chdir($archivedir);
my ($WRITEME);
my $program= "| \"$bindir/cpio\" -o -O arch.cpio.new ";
my $pid = open( $WRITEME, $program);
binmode $WRITEME; <<<<<<<<<<<<<<<<<<<<<<<<<<<<<solution
foreach my $f (@filelist){print $WRITEME "$f\n";}
close($WRITEME);
[download]

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Re: perl, cpio, and pipe by Anonyrnous Monk (Hermit) on Jan 13, 2011 at 15:06 UTC
Just a wild guess (I don't have a Windows system / cpio here to try). Maybe `cpio` doesn't like the `\r` that the file handle's `:crlf` layer (by default active on Windows) is adding when you say `print $WRITEME "$f\n";`. At least on Unix I get similar stat errors when I deliberately add `\r` to the filenames piped to `cpio` — not sure, though, how a Windows version of `cpio` would handle carriage returns... In other words, try `binmode $WRITEME`.	[reply] [d/l] [select]
Re^2: perl, cpio, and pipe by momo33 (Beadle) on Jan 13, 2011 at 15:43 UTC
binmode was the solution! Thank you!	[reply]
Re: perl, cpio, and pipe by Corion (Patriarch) on Jan 13, 2011 at 13:39 UTC
You don't check whether `$archivedir` exists and you can chdir into it. Use autodie or manually check for success: `chdir $archivedir or die "Couldn't chdir into '$archivedir': $!";` [download]	[reply] [d/l] [select]
Re^2: perl, cpio, and pipe by momo33 (Beadle) on Jan 13, 2011 at 14:27 UTC
In the actual code I do check (I build the filelist between chdir and cpio). After modification to make it more similar to the example-code I can assure you that chdir($archivedir) is executed correctly.	[reply]