use strict;
use warnings;

open OUT, '>', 'input.txt';
print OUT <<OUT;
contents of input.txt
OUT
close OUT;

sub Job_selection{
    my $select_job = shift;
    open (my $filehandle_in, "<", "input.txt") || die "Can't read input.txt: $!";
    open (my $filehandle_out, ">", "output_$select_job.txt") || die "Can't write output_$select_job.txt: $!";
    
    print $filehandle_out (<$filehandle_in>);
    
    close $filehandle_in;  
    close $filehandle_out;
}

Job_selection("1");
Job_selection("2");