var is the name of a NAGIOS_variable (see https://assets.nagios.com/downloads/nagioscore/docs/nagioscore/4/en/macrolist.html) (case insensitive)
default is a default value if \$NAGIOS_var\$ is blank (case sensitive)
word is an awk-compatible field number (potentially to use with <delim>)
delim is an awk-compatible field delimiter (defaults to space)
var the name of a case-insensitive NAGIOS_variable (defaults to "servicedesc")
default a default value if \$NAGIOS_var\$ is blank (case sensitive)
field an awk-compatible field number (potentially to use with <delim>)
delim an awk-compatible field delimiter (defaults to space, dash, and colon)
-u Convert the output to uppercase (useful for further levels of indirection)
suffix Take var result and use the it to get NAGIOS__[HOST|SERVICE|CONTACT]<result><suffix>
The value will always be trimmed of leading and/or trailing spaces/tabs.
If -f is used, then the result will be as if the request were:
If -f is used, then the result will be as if the request were as follows, unless the field starts with a negative, in which case it will read from the last word forward: