use strict;
use warnings;

use XML::LibXML;

my $dom = XML::LibXML->load_xml(
    location => $ARGV[0],
);

my %triggers;

foreach my $trigger ($dom->findnodes('/zabbix_export/triggers/trigger')) {
    $triggers{$trigger->findvalue('expression')} = $trigger->findvalue('name');
}

foreach my $template ($dom->findnodes('/zabbix_export/templates/template')) {
    my $templatename = $template->findvalue('./template');
    print "$templatename\n";
    foreach my $item ($template->findnodes('./items/item')) {
        my $name = $item->findvalue('name');
        my $key  = $item->findvalue('key');
        print "\t$name - $key\n";
        my (@itemtriggers) = grep {$_ =~ "\Q$templatename:$key.\E" } keys %triggers;
        foreach my $expression (@itemtriggers) {
            print "\t\t$triggers{$expression}   -   $expression\n";
        }
    }
}

> perl template-stats.pl zbx_export_templates-linux.xml
HS Template OS Linux
        Maximum number of opened files - kernel.maxfiles
                Configured max number of opened files is too low on {HOST.NAME}   -   {HS Template OS Linux:kernel.maxfiles.last(0)}<1024
        Maximum number of processes - kernel.maxproc
                Configured max number of processes is too low on {HOST.NAME}   -   {HS Template OS Linux:kernel.maxproc.last(0)}<256
        Memory used by sssd_nss - proc.mem[sssd_nss]
                Memory usage of sssd_nss suspiciously high   -   {HS Template OS Linux:proc.mem[sssd_nss].avg(5m)}>400M
        Number of running processes - proc.num[,,run]
                Too many processes running on {HOST.NAME}   -   {HS Template OS Linux:proc.num[,,run].avg(5m)}>30
        Count of $1 processes running as $2 - proc.num[java,root]
                There are java processes running as root   -   {HS Template OS Linux:proc.num[java,root].max(600)}>0
        Number of processes - proc.num[]
                Too many processes on {HOST.NAME}   -   {HS Template OS Linux:proc.num[].avg(5m)}>{$TRG_PROCNUM_THRESH}
        Host boot time - system.boottime
        Interrupts per second - system.cpu.intr
        Processor load (1 min average per core) - system.cpu.load[percpu,avg1]
                Processor load is too high on {HOST.NAME}   -   {HS Template OS Linux:system.cpu.load[percpu,avg1].avg({$TRG_CPULOAD_PERIOD})}>{$TRG_CPULOAD_THRESH}
                Active Zabbix agent is unreachable for 10 minutes   -   {HS Template OS Linux:system.cpu.load[percpu,avg1].nodata(10m)}=1
        Processor load (5 min average per core) - system.cpu.load[percpu,avg5]
        Processor load (15 min average per core) - system.cpu.load[percpu,avg15]
        Context switches per second - system.cpu.switches
        CPU $2 time - system.cpu.util[,idle]
        CPU $2 time - system.cpu.util[,interrupt]
        CPU $2 time - system.cpu.util[,iowait]
                Disk I/O is overloaded on {HOST.NAME}   -   {HS Template OS Linux:system.cpu.util[,iowait].avg(5m)}>20
        CPU $2 time - system.cpu.util[,nice]
        CPU $2 time - system.cpu.util[,softirq]
        CPU $2 time - system.cpu.util[,steal]
        CPU $2 time - system.cpu.util[,system]
        CPU $2 time - system.cpu.util[,user]
        Host name - system.hostname
                Hostname was changed on {HOST.NAME}   -   {HS Template OS Linux:system.hostname.diff(0)}>0
        Host local time - system.localtime
        Permissions of / - system.run[stat -c "%a" "/"]
                Permissions on / unexpected   -   {HS Template OS Linux:system.run[stat -c "%a" "/"].last()}<>{$PERMISSIONS_ROOT}
        Permissions of /home - system.run[stat -c "%a" "/home"]
                Permissions on /home unexpected   -   {HS Template OS Linux:system.run[stat -c "%a" "/home"].last()}<>755
        Owner of / - system.run[stat -c "%u" "/"]
                Owner of / not root   -   {HS Template OS Linux:system.run[stat -c "%u" "/"].last()}<>0
        Owner of /home - system.run[stat -c "%u" "/home"]
                Owner of /home not root   -   {HS Template OS Linux:system.run[stat -c "%u" "/home"].last()}<>0
        Free swap space - system.swap.size[,free]
        Free swap space in % - system.swap.size[,pfree]
                Lack of free swap space on {HOST.NAME}   -   {HS Template OS Linux:system.swap.size[,pfree].last(0)}<50
        Total swap space - system.swap.size[,total]
        System information - system.uname
                Host information was changed on {HOST.NAME}   -   {HS Template OS Linux:system.uname.diff(0)}>0
        System uptime - system.uptime
                {HOST.NAME} has just been restarted   -   {HS Template OS Linux:system.uptime.change(0)}<0
        Number of logged in users - system.users.num
        Checksum of $1 - vfs.file.cksum[/etc/passwd]
                /etc/passwd has been changed on {HOST.NAME}   -   {HS Template OS Linux:vfs.file.cksum[/etc/passwd].diff(0)}>0
        Last modification time of logrotate status file - vfs.file.time[/var/lib/logrotate.status]
                Logrotate status file not updated for two days   -   {HS Template OS Linux:vfs.file.time[/var/lib/logrotate.status].fuzzytime(2d)}=0
        Available memory - vm.memory.size[available]
                Lack of available memory on server {HOST.NAME}   -   {HS Template OS Linux:vm.memory.size[available].last(0)}<20M
        Total memory - vm.memory.size[total]