updated man page

diff --git a/fusefile.8 b/fusefile.8
index e2577c195a4073653d7b64a8eb1481177f7a1ad9..b4bd50d314f7b3504677285e7660e1fbc17da885 100644 (file)
--- a/fusefile.8
+++ b/fusefile.8
@@ -18,52 +18,67 @@ change size.
 The fragment arguments include the filename of a source file, and
 optionally start and end byte positions. All in all there five
 variations:
+
 .TP
-\fIfilename\fR
-include all of the file.
-.TP
-\fIfilename/\fR
-include all of the file named with "/" in the pathname. This case
-requires a final "/", since the last "/" separates the filename from
-the position details.
+\fIfilename\fR or \fIfilename/\fR
+include all of the file. A pathname that includes "/" must be ended
+with an extra "/" since that last "/" separates the filename from the
+range detail.
+
 .TP
-\fIfilename/from\fR
-include the file from the given start position, to end.
+\fIfilename/start:end\fR
+include the range from the given start to end. Either "start" or "end"
+or both may be omitted, to mean the beginning and end of the file
+respectively. If "start" or "end" are less than 0 then it means
+relative to the end of the file.
+
 .TP
-\fIfilename/-to\fR
-include the file from beginning to the given end position (not
-included).
+\fIfilename/start+length\fR
+include "length" bytes from the given start. A negative "start" means
+relative to the end of the file. If "length" is negative or omitted it
+means that position relative to the end.
+
 .TP
-\fIfilename/from-to\fR
-include the file from the given start position, up to the given end
-position (not included).
+\fIfilename/start\fR
+include bytes from the given start. This is the same as "/start+"
+
+.P
+Note that a negative start position is clipped to 0 and a too large
+end position  is clipped to the end of the file.
+
+.P
+Charater devices are treated as being of any given finite size, but
+have size 0 by default. For example, "/dev/zero/:100" means a fragment
+of 100 NUL bytes.
 
 .SH EXAMPLES
 
 Insert file "y" into file "x" at position 1200:
 .RS
-\fB$ fusefile -ononempty x x/-1200 y x/1200\fR
+\fB$ fusefile -ononempty x x/:1200 y x/1200:\fR
 .RE
 The bind mount shadows the original file "x", and presents the
-composite instead.
+fused file instead.
 
-Make file y be a swap of the beginning and end of file "x", at position 2442:
+Make fused file y be a swap of the beginning and end of file "x", at
+position 2442:
 .RS
-\fB$ fusefile y x/2442 x/-2442\fR
+\fB$ fusefile y x/2442: x/:2442\fR
 .RE
 
 .SH NOTES
 
-Note that \fBfusefile\fR opens the nominated source file(s) before
-bind mounting. With the fuse option \fI-ononempty\fR it will bind over
-an non-empty file, which may be useful. The source file descriptors
-remain open, but the source fragments are not recomputed. If a source
-file changes the fused file will present the new content. If a source
-is reduced in size, access will be inconsistent.
+Note that \fBfusefile\fR opens the nominated source file or files
+before bind mounting. With the fuse option \fI-ononempty\fR it will
+bind over an non-empty file, which may be useful. The source file
+descriptors remain open, but the source fragments are not recomputed.
+If a source file changes the fused file will present the new content.
+If a source is reduced in size, access will be inconsistent.
 
 If the mountpoint file doesn't exist, then \fBfusefile\fR creates it,
 and removes it when unmounted.
 
+
 .SH AUTHOR
 
 Ralph Rönnquist <ralph.ronnquist@gmail.com>