lastb:tldr:edd17

The sudo lastb --since ${YYYY-MM-DD} command is used to view the login attempts made on a Unix/Linux system that were unsuccessful.

Here's a breakdown of the command:

• sudo: It is a command that stands for "superuser do" and allows a user with administrative privileges to execute a command as another user, typically the root user.
• lastb: It is a command that displays the recent attempted logins to the system in a human-readable format. It reads the /var/log/btmp file where login attempts are recorded.
• --since ${YYYY-MM-DD}: It is an option used with the lastb command to specify the starting date and time from where you want to view the attempted logins. The ${YYYY-MM-DD} placeholder should be replaced with the actual desired date in the format Year-Month-Day.

By running this command with appropriate sudo privileges and providing a specific date, you can see the failed login attempts recorded in the system log since that specified date.