recover - recover a NetHack game interrupted by disaster
[ -d directory
] base1 base2 ...
Occasionally, a NetHack game will be interrupted by disaster when the game or
the system crashes. Prior to NetHack v3.1, these games were lost because
various information like the player's inventory was kept only in memory. Now,
all pertinent information can be written out to disk, so such games can be
recovered at the point of the last level change.
options tell recover
which files to process. Each base
option specifies recovery of a separate game.
option, which must be the first argument if it appears, supplies a
directory which is the NetHack playground. It overrides the value from
NETHACKDIR, HACKDIR, or the directory specified by the game administrator
during compilation (usually /usr/games/lib/nethackdir).
^?ALLDOCS For recovery to be possible, nethack
must have been compiled
with the INSURANCE option, and the run-time option checkpoint
have been on. ^: ^?INSURANCE For recovery to be possible, nethack
have been compiled with the INSURANCE option (this configuration was), and the
run-time option checkpoint
must also have been on. ^: This
configuration of nethack
was created without support for recovery. ^.
^. NetHack normally writes out files for levels as the player leaves them, so
they will be ready for return visits. When checkpointing, NetHack also writes
out the level entered and the current game state on every level change. This
naturally slows level changes down somewhat.
The level file names are of the form base.nn, where nn is an internal
bookkeeping number for the level. The file base.0 is used for game identity,
locking, and, when checkpointing, for the game state. Various OSes use
different strategies for constructing the base name. Microcomputers use the
character name, possibly truncated and modified to be a legal filename on that
system. Multi-user systems use the (modified) character name prefixed by a
user number to avoid conflicts, or "xlock" if the number of
concurrent players is being limited. It may be necessary to look in the
playground to find the correct base name of the interrupted game.
will transform these level files into a save file of the same
name as nethack
would have used.
must be able to read and delete files from the playground
and create files in the save directory, it has interesting interactions with
game security. Giving ordinary players access to recover
or setgid is tantamount to leaving the playground world-writable, with respect
to both cheating and messing up other players. For a single-user system, this
of course does not change anything, so some of the microcomputer ports install
For a multi-user system, the game administrator may want to arrange for all .0
files in the playground to be fed to recover when the host machine boots, and
handle game crashes individually. If the user population is sufficiently
can be installed with the same permissions the
executable has. In either case, recover
compiled from the distribution utility directory.
will overwrite existing savefiles of
the same name. Savefiles created by recover
are uncompressed; they may
be compressed afterwards if desired, but even a compression-using
will find them in the uncompressed form.
makes no attempt to find out if a base name specifies a game in
progress. If multiple machines share a playground, this would be impossible to
should be taught to use the nethack playground locking mechanism
to avoid conflicts.