
The basic format of the message can be controlled in a number of ways. The -f option or the LOGFORMAT environment variable specify the format using the following special sequences to specify the various parts of a message. The default format is: "%P %T %N %S:%L\n%M".
The formats are described in the following table:
Format  | 
Description  | 
%P(...)  | 
Priority level format: %d or %s  | 
%T(...)  | 
Time level format: all options supported by date cmd. There is also an additional format, %u, which is the UNIX time printed as an 8-digit hexidecimal number.  | 
%N  | 
Name of process  | 
%S  | 
Sourcefile name  | 
%L  | 
Line number  | 
%M(%r[={sepChr}])  | 
Message text. If %r is specified, the fields of the message are not expanded, but just entered raw. If a separator character is specified, it is placed between each raw field. If it is not specified, the FS character is placed between each field and a GS character is placed after the last field, which is just the way the fields would appear in the compressed logging files.  | 
%C  | 
The entire compressed message  | 
%%  | 
% character  | 
\{chr}  | 
Standard C backslash conventions  | 
...  | 
All other characters are printed as-is  | 
@{synthetic-fields}@
Synthetic fields are alternate names for %P, %T, %N, %S, %L, and %M fields, but they also give access to specific fields within the %M field by name or index. The legal synthetic fields are described in the following table:
Synthetic field  | 
Description  | 
@index@ OR @id@ OR @i@  | 
The absolute index of the message  | 
@symbol@ OR @sym@ OR @s@  | 
The symbolic name of the message  | 
@class@ OR @c@  | 
The class of the message  | 
@classIndex@ OR @ci@  | 
The index of the message within its class  | 
@priority@ OR @pri@ OR @p@  | 
Priority of the message in %s format  | 
@time@ OR @t@  | 
Equivalent to %T. These may be followed by specifiers like .sec, .hour, .mon, and so on, to get a specific part of the time.  | 
@program@ OR @prog@  | 
Equivalent to %N  | 
@file@  | 
Equivalent to %F  | 
@line@  | 
Equivalent to %L  | 
@field@[xxx] OR @f@[xxx]  | 
Where xxx is either a numerical index of the field or the symbolic name of the field  | 
@message@ OR @msg@ OR @m@  | 
The fully expanded message  | 
@cmpmsg@  | 
The original compressed message  |