-RECOVER(6) RECOVER(6)
+
+
+
+RECOVER(6) 1993 RECOVER(6)
NAME
- recover - recover a NetHack game interrupted by disaster
+ recover - recover a NetHack game interrupted by disaster
SYNOPSIS
- recover [ -d directory ] base1 base2 ...
+ recover [ -d directory ] base1 base2 ...
DESCRIPTION
- 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.
-
- The base options tell recover which files to process. Each base option
- specifies recovery of a separate game.
-
- The -d 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 admin-
- istrator during compilation (usually /usr/games/lib/nethackdir).
-
- For recovery to be possible, the run-time option checkpoint must have
- been on.
-
- 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. Vari-
- ous 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. recover will transform these level files
- into a save file of the same name as nethack would have used.
-
- Since recover 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 through
- setuid 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 recover by default.
-
- 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 popu-
- lation is sufficiently trustworthy, recover can be installed with the
- same permissions the nethack executable has. In either case, recover
- is easily compiled from the distribution utility directory.
+ 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 per-
+ tinent information can be written out to disk, so such games
+ can be recovered at the point of the last level change.
+
+ The base options tell recover which files to process. Each
+ base option specifies recovery of a separate game.
+
+ The -d option, which must be the first argument if it
+ appears, supplies a directory which is the NetHack play-
+ ground. It overrides the value from NETHACKDIR, HACKDIR, or
+ the directory specified by the game administrator during
+ compilation (usually /usr/games/lib/nethackdir).
+
+ For recovery to be possible, nethack must have been compiled
+ with the INSURANCE option, and the run-time option check-
+ point must also have been on. 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 play-
+ ground to find the correct base name of the interrupted
+ game. recover will transform these level files into a save
+ file of the same name as nethack would have used.
+
+ Since recover 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 ordi-
+ nary players access to recover through setuid or setgid is
+ tantamount to leaving the playground world-writable, with
+ respect to both cheating and messing up other players. For
+
+
+
+January Last change: 9 1
+
+
+
+
+
+
+RECOVER(6) 1993 RECOVER(6)
+
+
+
+ a single-user system, this of course does not change any-
+ thing, so some of the microcomputer ports install recover by
+ default.
+
+ 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
+ trustworthy, recover can be installed with the same permis-
+ sions the nethack executable has. In either case, recover
+ is easily compiled from the distribution utility directory.
NOTES
- Like nethack itself, recover 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 nethack
- will find them in the uncompressed form.
+ Like nethack itself, recover will overwrite existing save-
+ files of the same name. Savefiles created by recover are
+ uncompressed; they may be compressed afterwards if desired,
+ but even a compression-using nethack will find them in the
+ uncompressed form.
SEE ALSO
- nethack(6)
+ nethack(6)
BUGS
- recover 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 determine.
+ recover makes no attempt to find out if a base name speci-
+ fies a game in progress. If multiple machines share a play-
+ ground, this would be impossible to determine.
+
+ recover should be taught to use the nethack playground lock-
+ ing mechanism to avoid conflicts.
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- recover should be taught to use the nethack playground locking mecha-
- nism to avoid conflicts.
+January Last change: 9 2
-4th Berkeley Distribution 7 December 2015 RECOVER(6)
projects / nethack / commitdiff