Ну и еще для полного счастья  2.6 есть
#  TAG: logformat
#    Usage:
#
#    logformat <name> <format specification>
#
#    Defines an access log format.
#
#    The <format specification> is a string with embedded % format codes
#    
#    % format codes all follow the same basic structure where all but
#    the formatcode is optional. Output strings are automatically escaped
#    as required according to their context and the output format
#    modifiers are usually not needed, but can be specified if an explicit
#    output format is desired.
#
#        % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
#    
#        "    output in quoted string format
#        [    output in squid text log format as used by log_mime_hdrs
#        #    output in URL quoted format
#        '    output as-is
#
#        -    left aligned
#        width    field width. If starting with 0 then the
#            output is zero padded
#        {arg}    argument such as header name etc
#
#    Format codes:
#
#        >a    Client source IP address
....
#        >h    Request header. Optional header name argument
#            on the format header[:[separator]element]
#        <h    Reply header. Optional header name argument
#            as for >h
.....
#        %    a literal % character