How to extend a program that works for one file to act on every file in a directory

Question

I wrote a program to check for misspellings or unused data in a text file. Now, I want to check all files in a directory using the same process.

Here are a few lines of the script that I run for the first file:

open MYFILE, 'checking1.txt' or die $!;
@arr_file = <MYFILE>;
close (MYFILE);

open FILE_1, '>text1' or die $!;
open FILE_2, '>Output' or die $!;
open FILE_3, '>Output2' or die $!;
open FILE_4, '>text2' or die $!;

for ($i = 0; $i <= $#arr_file; $i++) {

    if ( $arr_file[$i-1] =~  /\s+\S+\_name\s+ (\S+)\;/ ) {
           print FILE_1 "name : $i  $1\n";
    }

...

I used only one file, checking1.txt, to execute the script, but now I want to do the same process for all files in the all_file_directory

This isn't hard. What have you tried and what went wrong? Is this homework? — Borodin, Oct 20 '16 at 08:59
File::Find - http://search.cpan.org/~rjbs/perl-5.24.0/ext/File-Find/lib/File/Find.pm — yoniyes, Oct 20 '16 at 10:02
@yonyon100: Probably [`glob`](http://perldoc.perl.org/functions/glob.html) since no recursion is required. — Borodin, Oct 20 '16 at 10:45
@Borodin was in the middle of editing my answer to include that as well — yoniyes, Oct 20 '16 at 10:49

score 2 · Answer 1 · edited May 23 '17 at 12:19

Use an array to store file names and then loop over them. At the end of loop rename output files or copy them somewhere so that they do not get overwritten in next iteration.

my @files = qw(checking1.txt checking2.txt checking3.txt checking4.txt checking5.txt);
foreach my $filename (@files){
    open (my $fh, "<", $filename) or die $!;
    #perform operations on $filename using filehandle $fh
    #rename output files    
}

Now for the above to work you need to make sure the files are in the same directory. If not then:

Provide absolute path to each file in @files array
Traverse directory to find desired files

If you want to traverse the directory then see:

Also:

and give proper names to the variables. For eg:

@arr_file = <MYFILE>;

should be written as

@lines = <MYFILE>;

all my file are in the same directory, I got a lot of file actually more than 5 file,so I still can use as above? — ozzy, Oct 20 '16 at 09:01

score 2 · Answer 2 · answered Oct 20 '16 at 10:07

Your all files in same directory means put the program inside the directory then run it.

For read the file from a directory use glob

while (my $filename =<*.txt>) # change the file extension whatever you want
{

    open my $fh, "<" , $filename or die "Error opening $!\n";

    #do your stuff here

}

score 0 · Answer 3 · edited May 23 '17 at 11:48

Why not useFile::Find? Makes changing files in directories very easy. Just supply the start directory. It's not always the best choice, depends on your needs, but it's useful and easy almost every time I need to modify a lot of files all at once.
Another option is to just loop through the files, but in this case you'll have to supply the file names.
As mkHun pointed out a glob can be helpful.

How to extend a program that works for one file to act on every file in a directory

3 Answers3