set terminal png transparent size 640,240 set size 1.0,1.0 set output 'files_by_date.png' unset key set yrange [0:] set xdata time set timefmt "%Y-%m-%d" set format x "%Y-%m-%d" set grid y set ylabel "Files" set xtics rotate set ytics autofreq set bmargin 6 plot 'files_by_date.dat' using 1:2 w steps