Perhaps you haven't explained your goal very well, but in any case I'm sure your code as posted does not do what you want. If I understand it correctly:

• There is one directory full of files (so no need to do recursion over subdirectories).
• Each file contains a relatively small number of lines.
• Each line is a "name,value" pair (except the first line, which is just a timestamp).
• You want all the lines in a given file to joined into a single line, by converting line breaks into commas, so each file ends up being just "name,value,name,value,..."
• When that processing is done, you want to load all the file data into an excel spreadsheet, with each original source file being one row.

If that's the basic plan, I wouldn't bother with writing modified versions of every original file. Just output a single stream of data (store it all in a single file), having one line of text for each input file. Something like this:

#!/usr/bin/perl

use strict;  # you really should!

( @ARGV == 1 and -d $ARGV[0] ) or die "Usage: $0 dir_name > out.csv\n"
+;

my $dirname = shift;
opendir( DIR, $dirname ) or die "$dirname: $!";

my @files = grep /.+\.txt$/, readdir DIR;
for my $file ( @files ) {
    my ( $basename ) = ( $file =~ /(.+)\.txt$/ );
    if ( open( F, $file )) {
        my ( $date, @lines ) = <F>;
        chomp $date;
        chomp @lines;
        print join( ",", "sourcefile", $basename, "date", $date, @line
+s ), "\n";
        close F;
    }
    else {
        warn "$file: $!\n";
    }
}
[download]

(I'm assuming you want to keep track of the original file names where all of the output rows come from, as well as all the time-stamps.)

Of course, if it turns out that all the files have the same number of lines, and the same set of names in their various "name,value" pairs, and these names are always in the same order, a better input for excel would have a single line at the top with the names, and then each following line would just have the values in the proper order:

#!/usr/bin/perl

use strict;

( @ARGV == 1 and -d $ARGV[0] ) or die "Usage: $0 dir_name > out.csv\n"
+;

my $dirname = shift;
opendir( DIR, $dirname ) or die "$dirname: $!";

my ( $firstfile, @files ) = grep /.+\.txt$/, readdir DIR;

open( F, $firstfile ) or die "$firstfile: $!";
my ( @names, @values );
my ( $basename ) = ( $firstfile =~ /(.+)\.txt$/ );
my $date = <F>;
while (<F>) {
    chomp;
    my ( $n, $v ) = split /,/, $_, 2;
    push @names, $n;
    push @values, $v;
}
close F;
print join( ",", "sourcefile", "date", @names ), "\n";
print join( ",", $basename, $date, @values ), "\n";

for my $file ( @files ) {
    ( $basename ) = ( $file =~ /(.+)\.txt$/ );
    if ( open( F, $file )) {
        ( $date, @values ) = <F>;
        chomp $date;
        chomp @values;
        s/.+?,// for ( @values );      # delete the "name," parts
        print join( ",", $basename, $date, @values ), "\n";
        close F;
    }
    else {
        warn "$file: $!\n";
    }
}
[download]

(Not tested)

If you're not sure whether all the files have the same set of names in the same order, it would be easy enough to check for that before you try to create the single data stream for importing to excel.

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.