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. The maximum length of a variable name is 127
bytes.
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/port/devenv.c
SEE ALSO
env(1), sh(1), env(2), sys-pctl(2)
Page 1 Plan 9 (printed 11/18/24)