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.TH fusefile 8
.SH NAME
fusefile \- FUSE file mount for combining file fragments

.SH SYNOPSIS
.B fusefile \fR[fuse options\fR] \fBmountpoint\fR \fIfilename/from-to\fR ...

.SH DESCRIPTION

\fBfusefile\fR is FUSE file mount that presents a series of fragments
of other files as a contiguous concatenation. It bind mounts a driver
on top of the file mountpoint to present the nominated file fragments
as a single, contiguous file. It accepts over-writing on the fused
file which gets distributed accordingly to the fragments, but cannot
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 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/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/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/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
.RE
The bind mount shadows the original file "x", and presents the
fused file instead.

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
.RE

.SH NOTES

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>