Trouble getting the right output from a file - regex

Question

Okay so here is my code:Pastebin
What i want to do is read from the file /etc/passwd and extract all the users with an UID over 1000 but less than 65000. With those users i also want to print out how many times they have logged in. And with this current code the output is like this:
user:15
User:4
User:4
The problem with this is that they haven't logged in 15 times or 4 times, because the program is counting every line that is output from the "last" command. So if i run the command "last -l user" it will look something like this:
user pts/0 :0 Mon Feb 15 19:49 - 19:49 (00:00)
user :0 :0 Mon Feb 15 19:49 - 19:49 (00:00)
wtmp begins Tue Jan 26 13:52:13 2016
The part that i'm interested in is the "user :0" line, not the others. And that is why the program outputs the number 4 instead of 1, like it should be. So i came up with a regular expression to only get the part that i need and it looks like this:
\n(\w{1,9})\s+:0
However i cannot get it to work, i only get errors all of the time.
Im hoping someone here might be able to help me.

Answer 1

I think this regexp will do what you want: m/^\w+\s+\:0\s+/
Here's some code that works for me, based on the code you posted... let me know if you have any questions! :)
#!/usr/bin/perl
use Modern::Perl '2009'; # strict, warnings, 'say'
# Get a (read only) filehandle for /etc/passwd
open my $passwd, '<', '/etc/passwd'
or die "Failed to open /etc/passwd for reading: $!";
# Create a hash to store the results in
my %results;
# Loop through the passwd file
while ( my $lines = <$passwd> ) {
my #user_details = split ':', $lines;
my $user_id = $user_details[2];
if ( $user_id >= 1000 && $user_id < 6500 ) {
my $username = $user_details[0];
# Run the 'last' command, store the output in an array
my #last_lines = `last $username`;
# Loop through the output from 'last'
foreach my $line ( #last_lines ) {
if ( $line =~ m/^\w+\s+\:0\s+/ ) {
# Looks like a direct login - increment the login count
$results{ $username }++;
}
}
}
}
# Close the filehandle
close $passwd or die "Failed to close /etc/passwd after reading: $!";
# Loop through the hash keys outputting the direct login count for each username
foreach my $username ( keys %results ) {
say $username, "\t", $results{ $username };
}

Answer 2

The shortest fix for your problem is to run the "last" output through "grep".
my #lastbash = qx(last $_ | grep ' :.* :');

Answer 3

So the answer is to use
my #lastbash = qx(last $_ | grep ":0 *:");
in your code.