xxxxxxxxxx
# echo "hello world" | tr " " .
hello.world
xxxxxxxxxx
string="x + x + y = 3y"
echo $string | sed 's/x/y/g'
# Result: y + y + y = 3y
# Breakdown:
# Pass echo result ("pipe") into sed which substitudes x with y.
# Sed Usage: sed '<option: substitute>/<delimeter>/<replacement>/<scale: global>