ECHO command

echo $SHELL = prints the default shell name
echo $OSTYPE = prints the operating system name
echo 'text' = prints what is held in the quotes
echo $HOME = prints home directory
echo $USER = who is currently using the system
echo $HISTFILE = location of history file
echo $HISTFILESIZE = history's set size
echo $HISTSIZE = history's set size
echo “test” | mail -v -s test xyz@abc.com = sending e-mail from a terminal