6 Cent OS commands you wont regret to learn

uname -p

your processor architecture, you can determine it by entering the command “uname -p” in a terminal, You should see  something like this:

i386, x86_64

cat /etc/issue

To find out your CentOS version just run, you should see something like this:
CentOS release 5.6 (Final)
Kernel \r on an \m

tac myfile.txt
To print a file in reverse order, Just a reverse of cat command.

wall hello everyone
Allows root or other users allowed to issue commands as root to send a message to everyones terminal.

head myfile.txt
To output the first part of files to the terminal, just a reverse of tail command.

source ~/.bash_profile
Reloads bash_profile / profile without starting a new shell session.