SWAP(8)                                                   SWAP(8)

     NAME
          swap - establish a swap file

     SYNOPSIS
          swap file

     DESCRIPTION
          Swap establishes a file or device for the system to swap on.
          If file is a device, the device is used directly; if 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 configured 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,
          such as kfs(4), can lead to deadlock; use raw devices or
          remote files instead.