Some linux command keywords useful you

If you are the master of GNU, reading this text is spend your time; If not this is maybe useful.
arch： show the cpu/framework
cat： show the content of the file
cd： change your current dictionary path to the specified
cksum： show the CRC value/file size
cp： same as copy/xcopy
date： show datetime
df： show free disk space
du： show the dictionary size
echo： show your word
groups： show your user
hostname： show your computer's name
id： show current user's id/group
man： search help of your command in the User guide
md5sum： show md5 value of you file
mkdir： create the dir
mv： move your file to other dir
ping： if you don't know......
ps： show running process
pwd： show current dir
sha1sum： show the sha1 value of file
stat： show the status of file
rm： delete the file!!!
rmdir： delete the dir
tty： show the current terminal
uname： try it. (ps: uname -a)
uptime： show how long time running of your system
w： show who is login and what is he/she/it doing now.
wc： show the file's line number (ps: wc -l lorem.txt)
who： show who is login the system.
whoami： show yourself
to be continued......