-fusefile
-========
+# fusefile
-This project implements a "fuse" device to mount as a single file that
-is a concatenation of fragments of one or more files. The fused file
-allows overwriting the parts files, but not changing their sizes, and
-only for parts files that are writable upon first access.
+This project implements a "fuse" device to mount a concatenation of
+fragments of one or more files as a single file.
-FUSE file mount for combining file fragments.
-
-== SYNOPSIS
+The __fused file__ allows writing to fragments (without changing their
+sizes); of course only for writable fragment files. The fused file may
+be set up with an __overlay file__ to capture changes instead of
+writing the underlying fragment files.
====
-*fusefile* [ _fuse options_ ] *mountpoint* +_filename_/from:to+ ...
+This is a nominal usage example to set up a fused file C consisting of
+files A and B:
+----
+$ fusefile C A B
+----
====
-## DESCRIPTION
-
-*fusefile* 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.
-
-The fragment arguments include the filename of a source file, and
-optionally start and end byte positions. All in all there five
-variations:
-
- * __filename__ include all of the file.
-
- * __filename/__ 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.
-
- * __filename/from__ include the file from the given start position, to end.
-
- * __filename/-to__ include the file from beginning to the given end position (not included).
-
- * __filename/from:to__ include the file from the given start position, up to the given end position (not included).
-
-## EXAMPLES
-
-.Insert file "y" into file "x" at position 1200:
-
- $ fusefile -ononempty x x/:1200 y x/1200:
-
-That mount will shadow the original file "x", and presents the
-fused file instead.
-
-.Make file y be a swap of the beginning and end of file "x", at position 2442:
-
- $ fusefile y x/2442: x/:2442
-
-.Replace a partition in an image file with a different file
-
- $ partx -oNR,START,SECTORS disk.raw
- NR START SECTORS
- 1 2048 2097152
- 2 2099200 409600
- 3 2508800 14268383
- # Replace partition 2 of 409600 sectors from 2099200 with
- # the file "insert.fat" clipped to 409600 sectors.
- $ fusefile -ononempty disk.raw \
- disk.raw/0:$(( 2099200*512 )) \
- insert.fat/0:$(( 409600*512 )) \
- disk.raw/$(( (2099200+409600)*512 )):
-
-
-## NOTES
-
-Note that **fusefile** opens the nominated source file(s) before bind
-mounting. With the fuse option __-ononempty__ it will bind over an
-non-empty file, which may be useful. The source file descriptors
-remain open, but the source fragments are not recomputed. If a source
-file changes or reduces in size "behind" the fused file, then anything
-may happen.
-
-If the mountpoint file doesn't exist, then **fusefile** creates it and
-removes it when unmounted.
-
-Unmounting is done with "fusermount -u __fused file__" as usual.
+====
+This is a nominal example of tearing down a fused file C:
+----
+$ fusermount -u C
+----
+====
-## AUTHOR
+See the +man page+ for usage details and some more examples.
-Ralph Rönnquist <ralph.ronnquist@gmail.com>
projects / rrq / fusefile.git / blobdiff