I'm too dusty to offer solid response, but the problem is in your looping structure.

Your while should close before that last foreach. And if you're creative you can reduce those 2 foreach's in the middle to 1.

This may do more harm than good, and probably won't run, but it should point in the right direction.

#!/usr/bin/perl
use strict;
use warnings;
use MIME::Lite;
use File::stat;
use Time::localtime;
use List::Util qw(sum);

my $OUT;
my %Accounts = ('AE202B01'=>0,
                'AE202B02'=>0,
                'AE202B03'=>0);

my $emd = `date --date '-30 min' +'%H'`;
chop ($emd);

$emd = "/tmp/pathtomyfiles/$emd.txt";

my $outfile = "/tmp/scripts/AESTUFF/AE202b.txt";

open (my $fh1, "-|" , "$emd") || die "Failed: $!\n" ;
open ($OUT, "> $outfile") || die "Cannot open $outfile"; # temp file t
+o which to write the formated output, if there is a match


while (my $line = <$fh1>) {
    chomp ($line);
    $line =~ s/ /\n/;

    if ( $line =~ /UserId1:(\w+),pairId.*/ ) {
        foreach $accounted_account ( keys @Accounts ){
            if ($accounted_account==$1){
               $Accounts{$accounted_account}++;
            }
        }
    }
}


foreach my $counted (sort keys %Accounts) {
    printf OUT "%-31s %s\n", $counted, $Accounts{$counted};
}

close ($OUT);
[download]