Provided by: nethack-common_3.4.3-15build1_amd64 bug


       recover - recover a NetHack game interrupted by disaster


       recover [ -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.

       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   administrator   during   compilation   (usually

       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.  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.  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  population  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.


       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.




       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  mechanism  to  avoid