Moving to GitHub, slowly

The software on this pages will slowly be moved to GitHub https://github.com/hilbix/. The CVS repository will be migrated to GIT as well, so the history will be preserved, a bit. See FAQ.

Scylla and Charybdis, mvatom - Tools

The tools are developed under Linux with ESR's paradigm release early, release often in mind.
So you can consider this beta software, or alpha, or pre-alpha, or even worse ;)

Have a look in the download directory for all downloads.
As always here, all you get is the source. No binaries here.

mvatom 0.4.4-20110825-142933

Move files by atomic rename instead of copy.

⇒ ⇒ ⇒ The development shifted to another location. All future versions will be published at https://github.com/hilbix/mvatom   ⇐ ⇐ ⇐

Post-modern mv implementations re-invented a wheel which is no more round. If they cannot move they do a copy/unlink() operation which is unsatisfying, as when the unlink() fails you stay with the copy which was insanely done.

mv shall be an atomic operation. However you cannot switch mv into atomic mode. This version here does what mv is supposed to do:

It renames the target and fails if it cannot do the rename (but beware the common NFS bug in such a situation). In unsafe mode it does this using the rename() operation (note that rename() has a possible race condition which may overwrite a destination unconditionally, if it is created after mvatom has checked the presence of the destination), in safe mode (will be introduced in 0.5.0) it will use hardlink/unlink. The move is "atomically" in respect to the destination either is there completely or missing, it is not "atomically" in the sense of "man 2 rename". If you need this, you need option -uf.

Another thing is that it only guesses something for the last argument like mv does if it is instructed to do so. So it always works reliably. You know what it does from looking at the command line, and if no heuristics are given this does not depend from the last arg beeing a directory or not.

If the destination is a directory this must be given as an option to mvatom. Also all options are simple and clear and there is no way to overwrite files, as mvatom never overwrites files (but beware the race condition in unsafe mode which was used before 0.5.0).

Also you can "move away" files with mvatom, too. This is done with the "backup" feature, where an existing destination can be renamed.

There now is a helper script:

cmpanddel.sh

deletes everything from a first directory which has an indentical match in a second directory. It shall be safe even against the weirdest situations where you simply cannot detect that the first directory in fact is the second one, thus accidentally deleting a whole directory tree. The protection is done by renaming the source first with mvatom. It is not race condition free, so it is thought for all those lazy experienced sysadmins out there who exactly know what they are doing.

The helper "dirlist" now is in a separate package. Example use:

dirlist -0p DIRa | mvatom -0dDIRb -

History:

License and Disclaimer All you can see here is free software according to the GNU GPL. Copyright (C)2000-2011 by Valentin Hilbig Note that the software comes with absolutely no warranty of any kind. You use the software at your own risk. Valentin Hilbig cannot be hold responsible for any unintended damage, lost data or malfunction of the software you can find here.