[Seisunix] Help with Plotting twt vs distance plot

Hi, Greetings! I am working on marine multichannel seismic data. To see structural features, I need to plot twt vs distance plot for last 56 km of the line. It is a very long line and I want to observe only the feaures of last 56 km. However, I am struggling a lot to set x axis values. I typed suwind < 5thshot.su tmin=0 tmax=4 j=600 | sugain jon=5 | sufilter f=0,5,10,20 amps=0.,0.,1.,1., | supsimage perc=99 > 5th.ps

It has given me the image of th whole line. Whereasm I am expecting an image like the image I have attached. Please help me out with making such an image. Thanks.