-.TH MHSHOW %manext1% "February 16, 2014" "%nmhversion%"
+.TH MHSHOW %manext1% "February 18, 2014" "%nmhversion%"
.\"
.\" %nmhwarning%
.\"
.PP
.RS 5
.nf
-.ta \w'%F 'u
+.ta \w'%F 'u
%a Insert parameters from Content-Type field
-%{charset} Insert the charset value from the Content-Type field
+%{parameter} Insert the parameter value from the Content-Type field
%e exclusive execution
%f Insert filename containing content
%F %e, %f, and stdin is terminal not content
.B mhshow
to wrap things up immediately.
.PP
+The {parameter} escape is typically used in a command line argument
+that should only be present if it has a non-null value. Its value
+will be wrapped with single quotes if the escape is not so wrapped.
+Shell parameter expansion can construct the argument only when it is
+non-null, e.g.,
+.PP
+.RS 5
+.nf
+mhshow-show-text/html: charset=%{charset};
+ w3m ${charset:+-I $charset} -T text/html %F
+.fi
+.RE
+.PP
+That example also shows the use of indentation to signify continuation:
+the two text lines combine to form a single entry.
+.PP
Note that if the content being displayed is multipart, but not one of
the subtypes listed above, then the f- and F-escapes expand to multiple
filenames, one for each subordinate content. Further, stdin is not
.PP
.RS 5
.nf
-mhshow-show-text/plain: %pmoreproc '%F'
-mhshow-show-message/rfc822: %pshow -file '%F'
+mhshow-show-text/plain: %pmoreproc %F
+mhshow-show-message/rfc822: %pshow -file %F
.fi
.RE
.PP
.RS 5
.nf
mhshow-show-audio/basic: raw2audio 2>/dev/null | play
-mhshow-show-image: xv '%f'
+mhshow-show-image: xv %f
mhshow-show-application/PostScript: lpr -Pps
.fi
.RE
.PP
-Note that when using the f- or F-escape, it's a good idea to use
-single-quotes around the escape. This prevents misinterpretation by
-the shell of any funny characters that might be present in the filename.
+If an f- or F-escape is not quoted with single quotes, its expansion
+will be wrapped with single quotes.
.PP
Finally,
.B mhshow