man.postnix Miscellaneous man pages of Plan 9 related material

     RAMFILE(4)                                             RAMFILE(4)

     NAME
          ramfile - synthesise file

     SYNOPSIS
          ramfile file [ data ]

     DESCRIPTION
          Ramfile puts a virtual file in the name space at file, and
          services file requests on it.  Data written to the file is
          stored in ramfile's memory; read requests return the previ-
          ously stored data.  If the optional data argument is pro-
          vided, the file will initially contain that text.  The par-
          ent directory of file must exist; ramfile creates a union
          mount on that directory, and if file previously existed, the
          synthesised file will hide it.

          Ramfile uses sys-file2chan(2), which simplifies implementa-
          tion but prevents it from knowing when the file has been
          truncated.  Instead, it truncates the file on any write to
          the start of the file (offset 0), allowing cp(1) to copy in
          new contents, and text editors to edit it.  Indeed, the file
          will be usable by all applications that do not rely on
          updating parts of the file in place, or if they do, do not
          update the start of the file.

     SOURCE
          /appl/cmd/ramfile.b

     SEE ALSO
          bind(1), sys-file2chan(2), srv(3), memfs(4)

     BUGS
          Ramfile cannot tell when the path has been unmounted; the
          only option is to kill(1) it.
          The file always appears to have zero length to sys-stat(2),
          which prevents loading a Dis file from it.

     Page 1                       Plan 9            (printed 10/29/25)