Bootlogd records boot messages.

Activate bootlogd

You do this by editing /etc/default/bootlogd, this is not enabled by default:

# Run bootlogd at startup ?
BOOTLOGD_ENABLE=yes

When the system is restarted, userspace messages will be logged to /var/log/boot.

Reading /var/log/boot file

Parts of a boot message sometimes can be wrapped with an ASCII color sequences, e.g. "failed" string after unsuccessful init action. bootlogd writes ^[ characters to its log file instead of actual ASCII escape character. To view colored strings via less as expected, you must replace ^[ characters with actual escape character and tell less to output ASCII color escape sequences in "raw" form:

sed $'s/\^\[/\E/g' /var/log/boot | less -R