What information will be returned when an administrator executes the command below? # last -f /var/log/btmp

Successful logins are stored in /var/log/wtmp and are displayed by running 'last' without the '-f /var/log/btmp' flag.

Erasing bash history requires commands such as 'history -c' or manually modifying ~/.bash_history - the 'last' command has no such function.

The 'last' command only reads log files and does not modify or delete them; removing /var/log/btmp requires separate commands like 'rm' or '> /var/log/btmp' with root privileges.

The 'last' command by default reads /var/log/wtmp for successful login records, but when invoked with '-f /var/log/btmp', it reads the btmp file instead. The btmp file is the binary log maintained by Linux PAM that records all bad (failed) login attempts, making this command useful for auditing unauthorized access attempts.