Edit: /usr/share/doc/pam/txts/README.pam_env (3627B)
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 are taken from the config
file /etc/security/pam_env.conf. An alternate file can be specified with
the conffile option.
Second a file (/etc/environment by default) with simple KEY=VAL pairs on
separate lines will be read. With the envfile option an alternate file can
be specified. And with the readenv option this can be completly disabled.
Third it will read a user configuration file ($HOME/.pam_environment by
default). The default file file can be changed with the user_envfile
option and it can be turned on and off with the user_readenv option.
Since setting of PAM environment variables can have side effects to other
modules, this module should be the last one on the stack.
OPTIONS
conffile=/path/to/pam_env.conf
Indicate an alternative pam_env.conf style configuration file to
override the default. This can be useful when different services
need different environments.
debug
A lot of debug information is printed with syslog(3).
envfile=/path/to/environment
Indicate an alternative environment file to override the default.
The syntax are simple KEY=VAL pairs on separate lines. The export
instruction can be specified for bash compatibility, but will be
ignored. This can be useful when different services need different
environments.
readenv=0|1
Turns on or off the reading of the file specified by envfile (0 is
off, 1 is on). By default this option is on.
user_envfile=filename
Indicate an alternative .pam_environment file to override the
default.The syntax is the same as for /etc/environment. The
filename is relative to the user home directory. This can be
useful when different services need different environments.
user_readenv=0|1
Turns on or off the reading of the user specific environment file.
0 is off, 1 is on. By default this option is off as user supplied
environment variables in the PAM environment could affect behavior
of subsequent modules in the stack without the consent of the
system administrator.
EXAMPLES
These are some example lines which might be specified in
/etc/security/pam_env.conf.
Set the REMOTEHOST variable for any hosts that are remote, default to
"localhost" rather than not being set at all
REMOTEHOST DEFAULT=localhost OVERRIDE=@{PAM_RHOST}
Set the DISPLAY variable if it seems reasonable
DISPLAY DEFAULT=${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
XDG_DATA_HOME @{HOME}/share/
Silly examples of escaped variables, just to show how they work.
DOLLAR DEFAULT=\$
DOLLARDOLLAR DEFAULT= OVERRIDE=\$${DOLLAR}
DOLLARPLUS DEFAULT=\${REMOTEHOST}${REMOTEHOST}
ATSIGN DEFAULT="" OVERRIDE=\@