RECOVER(6)                       Games Manual                       RECOVER(6)



NAME
       recover - recover a NetHack game interrupted by disaster

SYNOPSIS
       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).

       ^?ALLDOCS For recovery to be possible, nethack must have been  compiled
       with the INSURANCE option, and the run-time option checkpoint must also
       have been on.  ^: ^?INSURANCE For recovery to be possible, nethack must
       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.  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.

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.

SEE ALSO
       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  should  be taught to use the nethack playground locking mecha-
       nism to avoid conflicts.

COPYRIGHT
       This  file  is  Copyright  (C)  Kenneth  Lorber,   2022   for   version
       NetHack-3.7:1.12.   NetHack  may  be freely redistributed.  See license
       for details.



NETHACK                         8 February 2022                     RECOVER(6)
