pam_env.conf(5) - Man pages

PAM_ENV.CONF(5)                 Linux-PAM Manual                PAM_ENV.CONF(5)

NAME
       pam_env.conf, environment - the environment variables config files

DESCRIPTION
       The /etc/security/pam_env.conf file specifies the environment variables
       to be set, unset or modified by pam_env(8). When someone logs in, this
       file is read and the environment variables are set according.

       Each line starts with the variable name, there are then two possible
       options for each variable DEFAULT and OVERRIDE. DEFAULT allows an
       administrator to set the value of the variable to some default value, if
       none is supplied then the empty string is assumed. The OVERRIDE option
       tells pam_env that it should enter in its value (overriding the default
       value) if there is one to use. When OVERRIDE is not used, "" is assumed
       and no override will be done.

       VARIABLE [DEFAULT=[value]] [OVERRIDE=[value]]

       (Possibly non-existent) environment variables may be used in values
       using the ${string} syntax and (possibly non-existent) PAM_ITEMs as well
       as HOME and SHELL may be used in values using the @{string} syntax. Both
       the $ and @ characters can be backslash escaped to be used as literal
       values values can be delimited with "", escaped " not supported. Note
       that many environment variables that you would like to use may not be
       set by the time the module is called. For example, ${HOME} is used below
       several times, but many PAM applications don't make it available by the
       time you need it. The special variables @{HOME} and @{SHELL} are
       expanded to the values for the user from the corresponding passwd entry.

       The "#" character at start of line (no space at front) can be used to
       mark this line as a comment line.

       The /etc/environment file specifies the environment variables to be set.
       The file must consist of simple NAME=VALUE pairs on separate lines. The
       pam_env(8) module will read the file after the pam_env.conf file.

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  DEFAULT=@{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=\@

SEE ALSO
       pam_env(8), pam.d(5), pam(7), environ(7)

AUTHOR
       pam_env was written by Dave Kinchlea <kinch@kinch.ark.com>.

Linux-PAM                          06/29/2025                   PAM_ENV.CONF(5)

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