awk

Prepend string to each line

echo "world" | awk '{print "hello " $0}'
hello world

Get the ith element (separated by tabs/space)

cat file | awk '{print $2}'

Note: here its for the second element

Get the element according to a regex

echo "total 500K othter stuff" | awk '/[0-9]K/{print $2}'
# 500K