X-Git-Url: https://diplodocus.org/git/nmh/blobdiff_plain/b5c7fff31a2d48e3197571dd18a2638f13db1181..df02833a36f5525edb5b274fb67ca46aa4e5e6c5:/man/mhshow.man?ds=inline

diff --git a/man/mhshow.man b/man/mhshow.man
index 7cb76cf1..03ca5f82 100644
--- a/man/mhshow.man
+++ b/man/mhshow.man
@@ -1,4 +1,4 @@
-.TH MHSHOW %manext1% "February 9, 2014" "%nmhversion%"
+.TH MHSHOW %manext1% "February 18, 2014" "%nmhversion%"
 .\"
 .\" %nmhwarning%
 .\"
@@ -224,16 +224,17 @@ The display string may contain the following escapes:
 .PP
 .RS 5
 .nf
-.ta \w'%F  'u
-%a	Insert parameters from Content-Type field
-%e	exclusive execution
-%f	Insert filename containing content
-%F	%e, %f, and stdin is terminal not content
-%l	display listing prior to displaying content
-%p	%l, and ask for confirmation
-%s	Insert content subtype
-%d	Insert content description
-%%	Insert the character %
+.ta \w'%F        'u
+%a	   Insert parameters from 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
+%l	   display listing prior to displaying content
+%p	   %l, and ask for confirmation
+%s	   Insert content subtype
+%d	   Insert content description
+%%	   Insert the character %
 .fi
 .RE
 .PP
@@ -257,6 +258,22 @@ control-\\) will tell
 .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
@@ -268,8 +285,8 @@ behaves as if these profile entries were supplied and supported:
 .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
@@ -299,14 +316,13 @@ Example entries might be:
 .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