Reset linux console log level

• Get current console print log level:

sysctl kernel.printk

For instance, if the output is 4 4 1 7, you can reset it.

• Reset console print log level:

sysctl -w kernel.printk="2 4 1 7"

CUR = current severity level; only messages more important than this level are printed
DEF = default severity level assigned to messages with no level
MIN = minimum allowable CUR
BTDEF = boot-time default CUR

While another saying is console_loglevel, default_message_loglevel, minimum_console_loglevel, default_console_loglevel. Refer to here.

Log level 7 4 1 7 to 3 4 1 3 is demonstrated as below:

                     CUR  DEF  MIN  BTDEF
0 - emergency        x              x                        
1 - alert            x         x    x
2 - critical         x              x
3 - error            x              x
4 - warning          x    x         x
5 - notice           x              x
6 - informational    V              V
7 - debug            

                     CUR  DEF  MIN  BTDEF
0 - emergency        x              x                        
1 - alert            x         x    x
2 - critical         x              x
3 - error            V              V
4 - warning               x         
5 - notice                           
6 - informational                   
7 - debug         

Refer to Severity_levels.