pam_env ? PAM module to set/unset environment variables

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DESCRIPTION

The pam_env PAM module allows the (un)setting of environment variables.
Supported is the use of previously set environment variables as well as 
PAM_ITEMs such as PAM_RHOST.

By default rules for (un)setting of variables is taken from the config file /
etc/security/pam_env.conf if no other file is specified.

This module can also parse a file with simple KEY=VAL pairs on separate lines
(/etc/environment by default). You can change the default file to parse, with
the envfile flag and turn it on or off by setting the readenv flag to 1 or 0
respectively.

Since setting of PAM environment variables can have side effects to other
modules, this module should be the last one on the stack.

OPTIONS

conffile=/path/to/pam_env.conf

    Indicate an alternative pam_env.conf style configuration file to override
    the default. This can be useful when different services need different
    environments.

debug

    A lot of debug information is printed with syslog(3).

envfile=/path/to/environment

    Indicate an alternative environment file to override the default. This can
    be useful when different services need different environments.

readenv=0|1

    Turns on or off the reading of the file specified by envfile (0 is off, 1
    is on). By default this option is on.

user_envfile=filename

    Indicate an alternative .pam_environment file to override the default. This
    can be useful when different services need different environments. The
    filename is relative to the user home directory.

user_readenv=0|1

    Turns on or off the reading of the user specific environment file. 0 is
    off, 1 is on. By default this option is off as user supplied environment
    variables in the PAM environment could affect behavior of subsequent
    modules in the stack without the consent of the system administrator.

EXAMPLES

These are some example lines which might be specified in /etc/security/
pam_env.conf.

Set the REMOTEHOST variable for any hosts that are remote, default to
"localhost" rather than not being set at all

      REMOTEHOST     DEFAULT=localhost OVERRIDE=@{PAM_RHOST}


Set the DISPLAY variable if it seems reasonable

      DISPLAY        DEFAULT=${REMOTEHOST}:0.0 OVERRIDE=${DISPLAY}


Now some simple variables

      PAGER          DEFAULT=less
      MANPAGER       DEFAULT=less
      LESS           DEFAULT="M q e h15 z23 b80"
      NNTPSERVER     DEFAULT=localhost
      PATH           DEFAULT=${HOME}/bin:/usr/local/bin:/bin\
      :/usr/bin:/usr/local/bin/X11:/usr/bin/X11


Silly examples of escaped variables, just to show how they work.

      DOLLAR         DEFAULT=\$
      DOLLARDOLLAR   DEFAULT=        OVERRIDE=\$${DOLLAR}
      DOLLARPLUS     DEFAULT=\${REMOTEHOST}${REMOTEHOST}
      ATSIGN         DEFAULT=""      OVERRIDE=\@


