check_multi -f <config file> | -x command [-n name] [-t timeout] [-T TIMEOUT] [-r level] [-l libexec_path] [-s option=value] [-w <expr>] [-c <expr>] [-u <expr>] [-o <expr>] [-h][-v][-V]

config file(s) which contain(s) commands to be executed
See the special section for the format of this config file and compare the sample config file in the contrib directory.

1. You can specify multiple config files: -f <file1> -f <file2> …
2. If <file> is a directory, all *.cmd files in this directory are included and parsed in alphabetical order.

multi plugin name (shown in output)
default: none

This option can be used to do some descriptive tagging, e.g. SYSTEM, ORACLE, WEB etc.

timeout for one command
default: 10

This option defines the timeout for a child plugin. 10 seconds is a often used default in Nagios plugins. Normally this value does not have to be changed.

TIMEOUT for all commands
default: 60

This value (BIG T stands for the parent plugin, small t for the child plugins, please don't mix them ) limits the overall plugin runtime. Please note that Nagios itself has a timeout threshold for its service checks (service_check_timeout=60). After this timeout Nagios kills the service check. If you specify a greater timeout for the check_multi (BIG T), you consequently have to increase the nagios value for service_check_timeout accordingly. Otherwise you wouldn't see the cause for the check_multi timeout, but instead only the nagios timeout message.

The overall timeout (BIG T) provides a proper cancelling handling for the child plugins: if the parent plugin notices that a child plugin with its (small t) timeout extends the overall (BIG T) timeout, it does not execute it and reports this with the message “plugin cancelled due to global timeout”. The child plugin then gets the return code “UNKNOWN” This mimic ensures the proper runtime of the parent plugin and a (at least UNKNOWN) result for all plugins.

path to plugin
default: /usr/local/nagios/libexec

specify level of details in output (level is binary coded, just add all options)
default: 13

Note: you can also specify a string with combined numbers separated by '+', which should be easier to read .
Example '-r 13' = '-r 1+4+8'

Bit	Report-Option	Details / Output
1	Service name	24 plugins checked, 1 critical (http), 1 warning (disk_var), 0 unknown, 23 ok
2	HTML output	see Screenshot extended info. If you use this HTML output option, be sure to set escape_html_tags=0 in your cgi.cfg - otherwise you will see a lot of HTML tags
4	STDERR	If there is any STDERR output of the plugin it will be displayed in square brackets: [No such file or directory]
8	Performance data	Performance data is printed using Multi labels: disk_root_warning::check_disk::/=10549MB;6047;9675;0;12094
16	Full state list	MULTI CRITICAL - 16 plugins checked, 1 critical (disk_root_warning), 0 warning, 0 unknown, 14 ok
32	standard performance labels	Uses standard performance labels without Multi extension. This option is alternative to option 8
64	State label	OK,UNKNOWN,WARNING,CRITICAL state label is shown in front of child check output
128	PNP action link	If there is some performance data available a PNP action URL (the star) is shown at each child check (HTML output option required)
256	XML data	Print the complete data of all checks in a structured XML tree. This data can be used in wrapper scripts to realize customized output
512	Nagios2 compatibility	All output is displayed in 1 line MULTI CRITICAL, disk_root_warning DISK CRITICAL - free space: / 925 MB (8% inode=82%);, top top - 13:47:31 up 4 days, 21:35, 3 users, load average: 3.13, 3.01, 3.11
1024	Notes Icon	Shows a notes icon before each child check. Use the option -s notes_url=URL to specify the correct URL to your documentation
2048	Service definition	helper function to define passive services to be feeded by check_multi
4096	send_nsca	send all child checks as passive checks to the central Nagios server via send_nsca

set several options: –set <option>=<value> or -s <option>=<value>

If you need to set more than one option, do this by prepending each pair with its own -s phrase:
$ check_multi -s opt1=val1 -s opt2=val2 …

All –set options are stored in environment as NAGIOS_<varname> and can be reused either as environment variable $NAGIOS_<varname> or as check_multi variable $<varname>$.

Special meaning (defaults bold):

specify a command or eval line: - -execute “command [ procs ] = check_procs”
This is just a 1:1 copy of the command definition or eval definition line of the config file.

definition of the criteria for the WARNING state
see state definition

definition of the criteria for the CRITICAL state
see state definition

definition of the criteria for the UNKNOWN state
see state definition

definition of the criteria for the OK state
see state definition

print detailed help screen

shows debug output
(multiple -v creates additional output)

print version information