6.21. pam_motd - display the motd file
pam_motd.so [ motd=/path/filename ] [ motd_dir=/path/dirname.d ]
pam_motd is a PAM module that can be used to display arbitrary motd (message of the day) files after a successful login. By default, pam_motd shows files in the following locations:
/etc/motd |
/run/motd |
/usr/lib/motd |
/etc/motd.d/ |
/run/motd.d/ |
/usr/lib/motd.d/ |
Each message size is limited to 64KB.
If /etc/motd does not exist, then /run/motd is shown. If /run/motd does not exist, then /usr/lib/motd is shown.
Similar overriding behavior applies to the directories. Files in /etc/motd.d/ override files with the same name in /run/motd.d/ and /usr/lib/motd.d/. Files in /run/motd.d/ override files with the same name in /usr/lib/motd.d/.
Files the in the directories listed above are displayed in lexicographic order by name.
To silence a message, a symbolic link with target /dev/null may be placed in /etc/motd.d with the same filename as the message to be silenced. Example: Creating a symbolic link as follows silences /usr/lib/motd.d/my_motd.
ln -s /dev/null /etc/motd.d/my_motd
The MOTD_SHOWN=pam environment variable is set after showing the motd files, even when all of them were silenced using symbolic links.
-
motd=/path/filename -
The
/path/filenamefile is displayed as message of the day. Multiple paths to try can be specified as a colon-separated list. By default this option is set to/etc/motd:/run/motd:/usr/lib/motd. -
motd_dir=/path/dirname.d -
The
/path/dirname.ddirectory is scanned and each file contained inside of it is displayed. Multiple directories to scan can be specified as a colon-separated list. By default this option is set to/etc/motd.d:/run/motd.d:/usr/lib/motd.d.
When no options are given, the default behavior applies for both options. Specifying either option (or both) will disable the default behavior for both options.
- PAM_ABORT
-
Not all relevant data or options could be obtained.
- PAM_BUF_ERR
-
Memory buffer error.
- PAM_IGNORE
-
This is the default return value of this module.
The suggested usage for /etc/pam.d/login is:
session optional pam_motd.so
To use a motd file from a different location:
session optional pam_motd.so motd=/elsewhere/motd
To use a motd file from elsewhere, along with a corresponding .d directory:
session optional pam_motd.so motd=/elsewhere/motd motd_dir=/elsewhere/motd.d