man.postnix Miscellaneous man pages of Plan 9 related material

     ENV(3)                                                     ENV(3)

     NAME
          env - environment device

     SYNOPSIS
          bind #e /env

          /env/name

     DESCRIPTION
          The environment device serves a one-level directory giving
          access to environment variables and their values.  It is
          conventionally bound to /env.  The value of an environment
          variable name may be obtained by reading the file /env/name.
          If the file does not exist, the variable is unset and has
          the value nil.

          New environment variables are set by creating the corre-
          sponding file in /env and writing the required value to that
          file. Similarly environment variables are destroyed (unset)
          by removing the corresponding file.

          Processes sharing an `environment group' see the same files
          and contents; changes made by one process are seen by the
          others.  A process can insulate itself from further changes
          using the `FORKENV' option to sys-pctl(2), which creates a
          new environment group that is a copy of the old, but further
          changes in each are independent.  A new empty environment
          group is created by the `NEWENV' option to sys-pctl(2).

     SOURCE
          /os/port/devenv.c
          /emu/devenv.c

     SEE ALSO
          env(1), sh(1), env(2), sys-pctl(2)

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