pdr (*personal data recorder*) and pdx (*personal data expert*) are free applications to collect and evaluate mostly numeric, personal data.
The intended use case is to log individual medical data (blood sugar, blood pressure, body temperature, weight, heart rate and also medication). But you can
    
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     use the programs also for technical, sports, fitness, weather, environmental or financial data. The principle is a continuous flow of numbers in time that you want to monitor. Every data item can also be commented by text. [Less]