For splitting the commands, you can split before a ! sign

use strict;
use warnings;

my $command = '!book this is my test book !number 1222223 !book anothe
+r book"';
my @commands = split /(?=!)/, $command;
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Then if you want to ignore all but the first command, just use $commands[0]

This leaves trailing spaces in the commands. If you want to remove those too, split on /\s*(?=!)/ instead.