CSVからグラフを作る方法です。
yum install gnuplot
vim plotdata.plt --- set terminal png font "Vera.ttf,10" size 640,480 set output '/path/to/plot.png' set key spacing 1.3 set datafile separator "," set xdata time set timefmt "%s" set format x "%Y%m%d %H:%M" set xtics rotate by 90 plot '/path/to/csv' using ($1+32400):2 with linespoints pt 7 lw 2 ps 1 notitle ---
CSVはこんな感じ(unixtime,値)
1445579123,0.019 1445579401,0.032 1445580001,0.089 1445580601,0.100 1445581201,0.073 1445581801,0.078 1445582401,0.082 1445583001,0.107 1445583601,0.057
作成
export GDFONTPATH=$GDFONTPATH:/usr/share/fonts/ipa-gothic/:/usr/share/fonts/bitstream-vera/ gnuplot plotdata.plt