SWAP(8)                                                   SWAP(8)

     NAME
          swap - establish a swap file

     SYNOPSIS
          swap file

     DESCRIPTION
          Swap establishes a file for the system to swap on.  If file
          is an existing file, it is used for system swap. If it does
          not exist, a new file is created. If file is a directory, a
          unique file is created in that directory on which to swap.
          The environment variable swap is set to the full name of the
          resulting file.  The number of blocks available in the file
          or device must be at least the number of swap blocks config-
          ured at system boot time.

          If a swap channel has already been set and no blocks are
          currently valid in the file the old file will be closed and
          then replaced. If any blocks are valid on the device an
          error is returned instead.

     SOURCE
          /sys/src/cmd/swap.c

     BUGS
          Swapping to a file served by a local user-level process will
          lead to deadlock if the process isn't made non-swappable
          (see the noswap ctl-message in proc(3)).

     SEE ALSO
          proc(3)