Collecting Data from Multiple Files

[SensesFail]

Hi,

I have 500 different data files that each contain one line of text. I would like to open each file, grab the text and write it to another file, so that when I am finished, I will have all the lines of data stored in one file.

Does anyone know of a way to accomplish this using Perl?

Thank you!

 

[KevinADC]

Is there anyway to get the filenames into a list? Like are they all in one directory or do they all have a common identifier in the name or file extension? If so:

@ARGV = (all the filenames);
open(OUT, ">>", 'path/to/file') or die "$!";
while(<>){
   print OUT "$_\n";
}

------------------------------------------
- Kevin, perl coder unexceptional!

 

[SensesFail]

All files are in the same directory, and they are named as output0.txt, output1.txt, ..., output499.txt

Thanks for the code KevinADC! I just have a few questions: Do I need to pass the name of each file to the program from the command line? And could you please briefly describe what the while loop is doing?

Thanks again!

 

[KevinADC]

You don't need to pass any filename to the script unless you wanted to look for the file in a different directory or change a search pattern or something else. As lons as you will always read from the same directory and the filenames remain consistent just call the script with no arguments:

use strict;
use warnings;
chdir('path/to/start/dir) or die "Can't chdir: $!"; 
@ARGV = glob("output*.txt");
open(OUT, ">>", 'path/to/file') or die "$!";
while(<>){
  print OUT "$_\n";
}
close OUT;
print "Finished\n";
exit();

If the input files have a newline on the end drop the \n in the print line;

The while(<>) construct opens each filename in the @ARGV array and reads each line in the file into $_.

------------------------------------------
- Kevin, perl coder unexceptional!

 

[KevinADC]

this line:

chdir('path/to/start/dir) or die "Can't chdir: $!";

is missing a quote after dir, should be:

chdir('path/to/start/dir') or die "Can't chdir: $!";

------------------------------------------
- Kevin, perl coder unexceptional!