I am trying to draw a few graphs relative to a time axis that should automatically draw anything from the samle starting 2 days back since time of plotting. I couldn’t figure it out with gnuplot’s mechanics, so did this

set xrange [system("date -d 'now-2days' '+%d-%m-%Y %H:%M:%S'"):]

but it does not seem to see output of the system() as a string

gnuplot> show xrange

        set xdata time
        set xrange [ "0021-06-21 00:00:00" : * ] noreverse writeback  # (currently ["0021-06-21 00:00:00":"2258-01-03 00:00:00"] )

What am I doing wrong?