The signature is composed of a horizontal rule and a one-line message consisting of version information and date and time. The default value of this option is 1. Any document option is ignored if input files are named in the command line. As generating the HTML title element is deferred until the call to .TH , any macros or other troff requests that produce output must not be used before the initial .TH . As HTML is lacking the concept of text size, the macro .SB is just an alias for .B , and .SM simply echoes its arguments.
Subsequent invocations cause the list style to change if appropriate.
A warning message is printed in this and other questionable situations. This method obviously fails if no break occurs in subsequent lines, but it works for the common, idiomatic use of hanging paragraphs in manual pages. Unroff Programmer's Manual.