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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | MODULE TYPES PROVIDED | RETURN VALUES | EXAMPLES | SEE ALSO | AUTHOR | COLOPHON |
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PAM_MOTD(8) Linux-PAM Manual PAM_MOTD(8)
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 in the directories listed above are displayed in
lexicographic order by name. Moreover, the files are filtered by
reading them with the credentials of the target user
authenticating on the system.
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/filename file 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.d directory 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.
Only the session module type is provided.
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
motd(5), pam.conf(5), pam.d(5), pam(8)
pam_motd was written by Ben Collins <[email protected]>.
The motd_dir= option was added by Allison Karlitskaya
<[email protected]>.
This page is part of the linux-pam (Pluggable Authentication
Modules for Linux) project. Information about the project can be
found at ⟨http://www.linux-pam.org/⟩. If you have a bug report
for this manual page, see ⟨//www.linux-pam.org/⟩. This page was
obtained from the project's upstream Git repository
⟨https://github.com/linux-pam/linux-pam.git⟩ on 2023-12-22. (At
that time, the date of the most recent commit that was found in
the repository was 2023-12-18.) If you discover any rendering
problems in this HTML version of the page, or you believe there is
a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
[email protected]
Linux-PAM Manual 12/22/2023 PAM_MOTD(8)
Pages that refer to this page: login(1), systemd.system-credentials(7)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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