command-metrics is a script that can periodally save measurements for things that can be measured using a shell command that prints a single integer or float value.
command-metrics also offers some basic analysis features like selecting a range and seeing how much each series changed both in absolute numbers and as a percentage during that period.
Data is stored in .csv files which ("per spec") use CRLF line endings, so if you keep command-metrics data in a git repo it's good to set:
git config core.whitespace cr-at-eol
for that particular repository. It will instruction git not to emit the usual trailing whitespace error for CR.
GPLv3