sed 's/foo/bar/'

sed -e 's/foo/bar/'

sed -e '/foo/i' -e 'bar' -e '/fred/a' -e 'barny' -e '/harry/c' -e 'potter' file

sed '/foo/ibar'$'n''/fred/abarney'$'n''/harry/cpotter' file

-e script, --expression=script

    add the script to the commands to be executed

$ sed -e "s/foo/bar/" -e "/FOO/d"