Question

What I am trying to do is get my program to recurse through a directory and for all of those files within the directory, search each file for the word “ERROR” and then print the instance of it out in a seperate file. I was able to do this without making it recursive, i.e. just entering which files to check manually in the cmd. I was wondering what the proper way to use ARGV when recursing is. Here is my code thus far:

#!/usr/bin/perl
use strict;
use warnings;
use File::Find;

my $dir = "c:/programs";

find(\&searchForErrors, $dir);

sub searchForErrors()
{
my $seen = 0;

if (-f){
    my $file = $_;
    my @errors = ();

    open FILE, $file;
    my @lines = <FILE>;
    close FILE;

    for my $line (@lines){
        if (/ERROR/ ){
        push(@errors, "ERROR in line $.\n");
        print FILE "ERROR in line $.:$1\n" if (/Error\s+(.+)/);
    }
    open FILE, ">$file";
    print FILE @lines;
    close FILE;
    }
}
}

What I need to know is how I can incorporate ARGV so that the program will read in each file in the directory, perform the search, and then output the results of the search to a file. I hope I have explained my question adequately, if you need any clarification, let me know what is confusing. The more explanation you can give with the answer, the better. Thank you!

Answer 1

ARGV is usually used to iterate over files provided from outside of Perl.

 $ find -type f --exec perl script.pl {} +

 # script.pl
 while (<>) {
     print "$ARGV:$.: $1\n" if /Error\s+(.+)/;
 } continue {
     close(ARGV) if eof;  # Reset $.
 }

But it’s not necessary. You could also do:

 use File::Find::Rule qw( );

 @ARGV = File::Find::Rule->file->in('.');
 while (<>) {
     print "$ARGV:$.: $1\n" if /Error\s+(.+)/;
 } continue {
     close(ARGV) if eof;  # Reset $.
 }

I prefer File::Find::Rule, but you could stick with File::Find for reasons that should be obvious if you compare the above snippet with the following snippet:

use File::Find qw( find );

@ARGV = ();
find({ wanted => sub { push @ARGV, $_ if -f }, no_chdir => 1 }, '.');

 while (<>) {
     print "$ARGV:$.: $1\n" if /Error\s+(.+)/;
 } continue {
     close(ARGV) if eof;  # Reset $.
 }

PS – You’re replacing each file with an exact copy of itself, and you’re populating an array you never use. I omitted that code from my version.