I released Cyclomatic Complexity Analyzer for shell script.
ShellMetrics - Cyclomatic Complexity Analyzer for shell script
It measure NLOC (Non-comment Line of Code), LLOC (Logical Lines of Code) and CCN (Cyclomatic Complexity number) of shell scripts including bash.
Here are sample of coverage report.
I'd say finding a virus on Linux will be hard (to my knowledge, there are no Linux viruses in the wild). Rootkits are a different thing: booting from a clean medium (e.g. a live CD), and running chkrootkit would come to mind.
chkrootkit is a well-known rootkit detector (I've used it in the past, many years ago – hadn't a reason to use it afterwards, luckily)...
The combination of Python/Jupyter/Pandas and graphing suites such as HoloViz should give you what you need with minimal coding and good interactivity.
You can get the full installation in a few simple steps:
Install Anaconda or Miniconda if you don't have it already
Open the conda prompt and
conda create -n holoviz python=3.7
conda activate holoviz
Yes, OBS Studio is your best option here, as it's very customizable.
OBS Studio here also.
Geogebra is a fantastic free option for the majority of mathmatical things. However, making graphs simply via drawing may prove difficult, and I couldn't find any software that would support this, so you'll probably have to use a simple painting software such as PAINT....