dmesg [ -c ] [ -n level ] [ -s bufsize ]
clears the ring buffer contents after printing.
sets the level at which logging of messages is done to the console.
uses a buffer of bufsize to query the kernel ring buffer. This is 8196 by default (this matches the default kernel syslog buffer size in 2.0.33 and 2.1.103). If you have set the kernel buffer to larger than the default then this option can be used to view the entire buffer.