Part of solving a problem effectively is choosing the right tool. In this case, trying to do it all in bash is probably a worse choice than something like Perl or Python, because:

• it will be more complicated to implement, debug and maintain
• it will use many more processes
• the performance is likely to be poor

If you would like help to write this in a more appropriate language, just ask.

…later…

OK, you chose Perl….

You could certainly do everything which you re trying to do in Perl itself. However, as you re unfamiliar with it, I ve put together a little toy program which should do what you re after.

#!/usr/bin/perl -w

use strict;

my %present;

while (<>) {  # loop over input lines
  if (/player [(.*?)(?:|d+.d+.d+.d+)?]:? (.*)/) {
    my $player = $1;
    my $event = $2;

    if ($event eq "joined the game") {
      $present{$player} = 1;
    } elsif ($event eq "has left the game voluntarily") {
      delete $present{$player};
    } elsif ($event =~ /^was autokicked/) {
      delete $present{$player};
    }
  }
}

foreach (sort keys %present) {
  print "$_
";
}

The output produced looks like this:

$ ./analyse inputfile
Jack
Jones
Samual

and you may wish to call it something like this from your bash script:

tail -1000 ghost.log | ./analyse

or even:

playerspresent=`tail -1000 ghost.log | ./analyse`

I ve tried to keep the Perl program as simple as is sensible. The only "difficult" bit is the regular expression. Essentially, it loops over the lines of input, trying to decide whether each line represents someone joining or leaving. If joining, the username is added to the %present hash; if leaving, it is removed. At the end, the names are listed in order.

Is this enough to get you back on track?

This might work for what you want. It assumes, probably unsafely, that if a player is listed an odd number of times in the combined joined and left lists that he is currently in the game (e.g. join or join-leave-join) while an even number of entries indicates that he has left (e.g. join-leave).

#!/bin/bash
joined=$(sed -n  s/[.*] [GAME: .*] player [(.*)|.*] joined the game/1/p  gamefile.txt)

left=$(sed -n  s/[.*] [GAME: .*] deleting player [(.*)].*/1/p  gamefile.txt)

saveIFS="$IFS"
IFS=$ 
 
players=("$(echo -e "$joined
$left" | sort | uniq -c)")
IFS="$saveIFS"

flag=0
echo -n " "
for i in "${players[@]}"
do
    if [[ $flag == 1 ]]
    then
        echo -n " ,  "
    fi
    j=($i)
    if (( ${j[0]}%2 == 1 ))
    then
        flag=1
        echo -n "${j[1]}"
    fi
done
echo " "

Result from your example data:

 Jack ,  Jones ,  Samual 

you can use gawk

awk  $11=="player" && ( $(NF-2)=="joined" || $12=="[Lobby]" ) {
 gsub(/[||.*]|:/,"",$12) ; player[$12]
}
$11=="deleting"{gsub(/[|]|:/,"",$13); delete player[$13]  }
END{
 for(i in player){  print i }
}  file

output

./shell.sh
Jones
Samual
Jack