Linux, oneTwoThree

001- tar.bz2
tar jxvf filename.tar.bz2

002- USB-to-Serial ==> CentOS-5.5 not support HL-340 driver by default. Suggest to used PL2303.
# lsusb
# dmesg

003- Find the path.
# whereis wish
wish: /usr/bin/wish8.5


004- dmesg

# dmesg | more ==> Show event by pages.

# dmesg -c ==> clear previous event.

005- kill (find out process id and then kill)
# kill -9 $( ps -ef | grep wdt | awk '{ print $2 }')

006- pgrep & pkill (list process name & kill)
# pgrep -l  [process name]
# pkill [process name]