/usr/share/munin/plugins/acpi is in munin-node 1.4.6-3ubuntu3.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 | #!/bin/sh
# -*- sh -*-
: <<=cut 
=head1 NAME
acpi - Munin plugin to monitor the temperature in different ACPI Thermal zones.
=head1 APPLICABLE SYSTEMS
Linux systems with ACPI support.
=head1 CONFIGURATION
Load the 'thermal_zone' kernel module and the plugin gets the thermal zones from /proc/acpi/thermal_zones/*/ automagically.
=head1 USAGE
Link this plugin to /etc/munin/plugins/ and restart the munin-node.
=head1 INTERPRETATION
The plugin shows the temperature from the different thermal zones. 
=head1 MAGIC MARKERS
 #%# family=auto
 #%# capabilities=autoconf
=head1 BUGS
None known.
=head1 VERSION
$Id:$
=head1 AUTHOR
Nicolai Langfeldt (janl@linpro.no) 2006-11-13
=head1 LICENSE
GPLv2
=cut
ATZ="$(echo /proc/acpi/thermal_zone/*/temperature)"
do_ () { # Fetch
    echo "$ATZ" | tr ' ' '\n' | awk -F'[ /\t]*' '{
         ZONE=$5
         getline < $0
         print ZONE".value "$2
    }'
    exit 0
}
do_config () {
    echo "graph_title ACPI Thermal zone temperatures"
    echo "graph_vlabel Celcius"
    echo "graph_category sensors"
    echo "graph_info This graph shows the temperature in different ACPI Thermal zones.  If there is only one it will usually be the case temperature."
    echo "$ATZ" |
    awk -F'[ /]' '{
         print $5".label "$5;
    }'
                  
}
do_autoconf () {
    for f in $ATZ; do
	test -r $f || {
	    echo "no (cannot read $f)"
	    exit 0
	}
    done
    echo yes
    exit 0
}
case $1 in
    config|autoconf|'')
	eval do_$1
esac
exit $?
 |