[Tfug] joining two large files on disk...

[Kramer Lee]

I don't know about the linux file systems, but to do what he is
talking about in the FAT file system, someone (not me) could write a
utility that finds the <EOF> sector entry in the file allocation
table(s) and change it to point to the first sector (the one pointed
to in the directory entry for the second file) of the second file,
then change the directory entry for the original file to be the
addition of the original file plus the size of the second file.  The
utility could change the original file name to whatever you wanted the
new file name to be.

This could be a dangerous utility, dangerous like dd.  Merging two
executable files, or anything with one executable file would probably
hose it up irreparably.  It sounds like a person would want to
consider carefully what multi-GB files should be merged this way.
Unless the utility saved the original directory information etc, it
wouldn't be recoverable, and as soon as the new big file is changed it
wouldn't be recoverable.