Expressions

Expressions are used for the filter, warning, critical and ok arguments.

Syntax

The basic syntax is <attribute> <operator> <value>. For a list and explanation of allowed operators see the operator list.

The list of possible attributes is documented along with each check plugin.

ex.:

filter="status = 'started'"

critical="count >= 1"

Logical Operator

To combine multiple expressions you can use logical operator and brackets.

Operator	Alias	Description	Example
and	&&	Logical and operator	count = 0 and state != 1
or	||	Logical or operator	used > 5 or free < 20

ex.:

filter="(status = 'started' or status = 'pending') and usage > 5%"

Operator

Operator	Alias / Safe expression	Types	Case Sens.	Description
=	==, is, eq	Strings, Numbers	Yes	Matches on exact equality, ex.: status = 'started'
!=	is not, ne	Strings, Numbers	Yes	Matches if value is not exactly equal. ex.: 5 != 3
like	ilike	Strings	No	Matches if value contains the condition (case insensitive substring match), ex.: status like "pend"
unlike	not like, not ilike	Strings	No	Matches if value does not contain the case insensitive substring, ex.: status unlike "stopped"
slike	strictlike	Strings	Yes	Matches a case sensitive substring, ex.: name slike "WMI"
not slike	not strictlike	Strings	Yes	Matches if a case sensitive substring cannot be found, ex.: name not slike "WMI"
~	regex, regexp	Strings	Yes	Performs a regular expression match, ex.: status ~ '^pend'
!~	not regex, not regexp	Strings	Yes	Performs a inverse regular expression match, ex.: status !~ 'stop'
~~	regexi, regexpi	Strings	No	Performs a case insensitive regular expression match, ex.: status ~~ '^pend'. An alternative way is to use //i as in status ~ /^pend/i
!~~	not regexi, not regexpi	Strings	No	Performs a inverse case insensitive regular expression match, ex.: status !~~ 'stop'
<	lt	Numbers	-	Matches lower than numbers, ex.: usage < 5%
<=	le, lte	Numbers	-	Matches lower or equal numbers, ex.: usage <= 5%
>	gt	Numbers	-	Matches greater than numbers, ex.: usage > 5%
>=	ge, gte	Numbers	-	Matches greater or equal numbers, ex.: usage >= 5%
in		Strings	Yes	Matches if element is in list ex.: status in ('start', 'pending')
not in		Strings	Yes	Matches if element is not in list ex.: status not in ('stopped', 'starting')

Other Operators

For backwards compatibility there more operators available:

Operator	Alias	Description	Example
''	str()	String constant	exe like str(winlogon.exe)