man.postnix Miscellaneous man pages of Plan 9 related material

     ENV(3)                                                     ENV(3)

     NAME
          env - environment variables

     SYNOPSIS
          bind #e /env

          /env/var1
          /env/var2
           ...

     DESCRIPTION
          The env device serves a one-level file directory containing
          files with arbitrary names and contents.  The intention is
          that the file name is the name of an environment variable
          (see rc(1)), and the content is the variable's current
          value.

          When a fork(2) system call creates a new process, both the
          parent and the child continue to see exactly the same files
          in the env device: changes made in either process can be
          noticed by the other.  In contrast, an rfork system call
          with the RFENVG bit set (see fork(2)) causes a split: ini-
          tially both process groups see the same environment files,
          but any changes made in one process group cannot be noticed
          by the other.

     SEE ALSO
          rc(1), fork(2)

     BUGS
          A write starting at an offset after the current extent of a
          file yields an error instead of zero filling.

     Page 1                       Plan 9            (printed 11/16/25)