This is a truly great example of a utility app ported--even if only intellectually--to Android from the FOSS world of Gnu/Linux (shameless plug for Gnu and the heroic Mr Richard Stallman  defender of Freedom for all). I use it a _lot_ in both ecosystems and think it's an ideal app. It works well  keeps everything unless you del it yourself  it looks pretty  and it stays out of the way until needed. It's exactly right. :^))
April 05 2017