Scripts
Scripts on Linux? But of course!
When you can do Python, theoretically you don't really have the need to know an OS-level scripting language and on Windows .bat files weren't a serious alternative but all in all I'm glad a can do a little bash.
I've come to use a mix of pure Bash scripts, pure Python scripts and scripts made with a framework (Invoke) which among others mixes Python and Bash easily.
These scripts are implemented as functions that can be called as if they were parameters to the framework, i.e. as inv[oke] <scriptname> <parameters>. Since I had made them with Fabric earlier I was used to calling them with binfab or fabsrv, and you still can (in fact you have to, or the framework won't know where to find the commands).
A list of invoke (and other) functions I currently have:
A subject I also want to name here is building and running unittests