loglevel — Set the default console log level.
Specify the initial console log level. Any log messages with levels less than this (that is, of higher priority) will be printed to the console, whereas any messages with levels equal to or greater than this will not be displayed.
The console log level can also be changed by the klogd program, or by writing the specified level to the /proc/sys/kernel/printk file.
The kernel log levels are:
The system is unusable.
Actions that must be taken care of immediately.
Non-critical error conditions.
Warning conditions that should be taken care of.
Normal, but significant events.
Informational messages that require no action.
Kernel debugging messages, output by the kernel if the developer enabled debugging at compile time.