#!/bin/bash
s='This is a test toRemove first line
This is a test toRemove second line toRemove'
sed '/toRemove.*toRemove/d' <<< "$s"
grep -v 'toRemove.*toRemove' <<< "$s"
IyEvYmluL2Jhc2gKcz0nVGhpcyBpcyBhIHRlc3QgdG9SZW1vdmUgZmlyc3QgbGluZQpUaGlzIGlzIGEgdGVzdCB0b1JlbW92ZSBzZWNvbmQgbGluZSB0b1JlbW92ZScKc2VkICcvdG9SZW1vdmUuKnRvUmVtb3ZlL2QnIDw8PCAiJHMiCmdyZXAgLXYgJ3RvUmVtb3ZlLip0b1JlbW92ZScgPDw8ICIkcyI=