gnuplot> plot "hr.txt" using 3:($4-$3)
gnuplot> plot "hr.txt" using ($4-$3):3
gnuplot> plot [0.3:1.5][18:10]  "hr.txt" using ($4-$3):3
gnuplot> plot [0.3:1.5][10:18]  "hr.txt" using ($4-$3):3
gnuplot> plot [0.3:1.5][18:10]  "hr.txt" using ($4-$3):3
gnuplot> plot [0.3:1.5][16:10]  "hr.txt" using ($4-$3):3
gnuplot> plot "m67V2i.txt" using 3:4
gnuplot> plot [*:*][0:0.5]  "m67V2i.txt" using 3:4
gnuplot> plot [*:*][0:0.1]  "m67V2i.txt" using 3:4
gnuplot> plot [*:16][0:0.1]  "m67V2i.txt" using 3:4
gnuplot> plot [*:16][0:0.1]  "m67B2i.txt" using 3:4
gnuplot> plot [0.3:1.5][16:10]  "hr.txt" using ($4-$3-0.01):($3+1.49)
gnuplot> plot [0.3:1.5][18:11]  "hr.txt" using ($4-$3-0.01):($3+1.49)
gnuplot> plot [0.3:1.5][17:11]  "hr.txt" using ($4-$3-0.01):($3+1.49)
gnuplot> set xlabel "B-V"
gnuplot> set ylabel "V Johnson mag"
gnuplot> replot
gnuplot> set ylabel "V "
gnuplot> replot
gnuplot> set title "kopica M 67"
gnuplot> replot
gnuplot> plot [*:16][0:0.1] "m67V2i.txt" using ($3+1.49):4
gnuplot> plot [*:18][0:0.1] "m67V2i.txt" using ($3+1.49):4
gnuplot> set xlabel "V"
gnuplot> replot
gnuplot> set ylabel "napaka v mag"
gnuplot> replot