pam_echo

pam_echo [debug] [file=filename]

debug
    Enables verbose debugging output to syslog.

file=filename
    Specifies a file containing the messages to be displayed. If not specified, messages are read directly from the PAM configuration.

The pam_echo module is a Pluggable Authentication Module (PAM) used to display messages to the user during the authentication process.

It reads messages from the PAM configuration file and prints them to the user's terminal. These messages can be customized to provide instructions, warnings, or other information relevant to the authentication stage.

pam_echo is commonly used for tasks such as displaying welcome messages, security notices, or prompts for specific actions.

The module offers simplicity and flexibility in controlling the information presented to users during authentication without requiring modifications to the underlying authentication system itself.

Messages displayed by pam_echo are displayed directly to the user's terminal, so sensitive information should not be included. Be aware of character encoding issues when displaying messages.

To use pam_echo, add it to the appropriate PAM configuration file (e.g., /etc/pam.d/login). The syntax typically involves specifying the module's path and any relevant parameters. Example:
`auth sufficient pam_echo.so file=/etc/security/welcome.txt`

Messages displayed by pam_echo are interpreted literally. You can use standard text formatting techniques to control their appearance.

The pam_echo module was developed as part of the PAM framework to provide a simple mechanism for displaying messages to users during the authentication process. It has been widely adopted due to its ease of use and adaptability.

pam(8)