dash shell scripting tutorial 3 - conditional logic and functions

Описание: In this lesson we will examine functions and conditional logic

cheat sheet
http://eriklievaart.com/cheat/linux/s...
http://eriklievaart.com/cheat/linux/s...

tutorials
http://www.grymoire.com/Unix/Sh.html
http://steve-parker.org/sh/sh.shtmL
https://en.wikibooks.org/wiki/Bourne_...

specification
https://pubs.opengroup.org/onlinepubs...