Format Specifications

snmptrapd interprets format strings similarly to printf(). It understands the following formatting sequences:

String	Description
%%	a literal %
%a	the contents of the agent-addr field of the PDU (v1 TRAPs only)
%A	the hostname corresponding to the contents of the agent-addr field of the PDU, if available, otherwise the contents of the agent-addr field of the PDU(v1 TRAPs only).
%b	PDU source address (Note: this is not necessarily an IPv4 address)
%B	PDU source hostname if available, otherwise PDU source address (see note above)
%h	current hour on the local system
%H	the hour field from the sysUpTime.0 varbind
%j	current minute on the local system
%J	the minute field from the sysUpTime.0 varbind
%k	current second on the local system
%K	the seconds field from the sysUpTime.0 varbind
%l	current day of month on the local system
%L	the day of month field from the sysUpTime.0 varbind
%m	current (numeric) month on the local system
%M	the numeric month field from the sysUpTime.0 varbind
%N	enterprise string
%q	trap sub-type (numeric, in decimal)
%P	security information from the PDU (community name for v1/v2c, user and context for v3)
%t	decimal number of seconds since the operating system epoch
%T	the value of the sysUpTime.0 varbind in seconds
%v	list of variable-bindings from the notification payload. These will be separated by a tab, or by a comma and a blank if the alternate form is requested
%V	specifies the variable-bindings separator. This takes a sequence of characters, up to the next % (to embed a % in the string, use \%)
%w	trap type (numeric, in decimal)
%W	trap description
%y	current year on the local system
%Y	the year field from the sysUpTime.0 varbind

In addition to these values, optional fields width and precision may also be specified, just as in printf(3), and a flag value. The following flags are supported:

• ‘-‘ (left justify)

• ‘0’ (use leading zeros)

• ‘#’ (use alternate form)

The "use alternate form" flag changes the behavior of various format string sequences:

• Time information will be displayed based on GMT (rather than the local time zone)

• The variable-bindings will be a comma-separated list (rather than a tab-separated one)

• The system uptime will be broken down into a human-meaningful format (rather than being a simple integer)

Examples

To get a message like 14:03 TRAP3.1 from humpty.ucd.edu you could use something like this:

snmptrapd -P -F "%02.2h:%02.2j TRAP%w.%q from %A\n"

If you want the same thing but in GMT rather than local time, use

snmptrapd -P -F "%#02.2h:%#02.2j TRAP%w.%q from %A\n"