&help xplot is a simple plotting program that lets you make graphs composed of points, lines, axes, and labels on the screen and on a printer. xplot reads data from an ASCII file containing columns of data separated by white spaces, i. e. spaces and tabs. You can plot any one of the columns against any other column. Type 'help xxx' for more information on command xxx. box -- to draw the axes. connect -- to connect the points with a line. cursor -- to use the mouse to set the current position. data -- to open a file for reading data. dot -- places a marker at the current position draw -- to draw from the current position to another point. ec -- to read the error column points (and vfield) erase -- to clear the display. errorbar -- to draw error bars expand -- to change the size of the point markers. hardcopy -- to send a Postscript plot to the printer, or to a given file hist -- connects x,y, pairs in histogram style input -- to run commands from a file. label -- to label the graph. limits -- to set the limits of the graph. lines -- to limit the number of points in the graph. ltype -- to change the line type. nosave -- to stop saving commands into a file. pc -- to read the p column points (see vfield) plot -- a combination of "data, xc 1, yc 2, limits, box, connect" points -- to plot the points. ptype -- to change the point type. quit -- to end the program. relocate -- to position the cursor for labeling. reverse -- to reverse the color of display (destroys contents on color display) save -- to save commands into a file. spawn -- to stop the program, but leave the graphics window alive title -- to put a title on the graph. vfield -- plots vector field tail in x,y length in pcol, angle in ecol wait -- wait the specified number of seconds or until a file changes xc -- to read the x column. xlabel -- to label the x axis. xlog -- takes the base 10 logarithm of data in x column xsixty -- to read x column in babylonian notation yc -- to read the y column. ylabel -- to label the y axis. ylog -- takes the base 10 logarithm of data in y column ysixty -- to read y column in babylonian notation &ptype ptype [ npoints ] [ solid ] If arguments are given, set the current point type to the given value; with no arguments, report the current point type. The first argument gives the number of points to the polygon used as a marker (3 = triangle, 4 = square, etc.); the second, if 0, specifies empty polygons; if 1, specifies filled-in polygons. &expand expand size Change the size of all point markers by a multiplicative factor given by the argument "size". The default sizes are given by size=1.0, so "expand 2.0" gives markers twice as big, and "expand 0.25" gives markers one-quarter as big as the default ones. This command changes the vfield vectors as well as the tick size on the error bars. <ype ltype [ value ] If an argument is given, set the current line type to the given value; with no argument, report the current point type. Possible types are: 0 = solid, 1 = dotted, 2 = dash-dotted, 3 = dashed. &reverse reverse Reverse the color of the screen so that what was previously black is white and the white is black. This command works only for the graphics window of the display. &data data filename Open the file "filename" for data input. "filename" can be an absolute pathname or pathname relative to the current directory. If it does not exist, the program will complain. &hardcopy hardcopy [filename] If no "filename" is given, sends the accumulated plot, in Postscript form, to the line printer. If a "filename" is given, the Postscript commands to make a copy of the current plot are placed into that file. &lines lines n1 n2 Limit the lines of the file from which data will be read so that only data between lines n1 and n2 (inclusive) will be used. Line numbers start at 1, not 0. &xc xc n Take data for the x coordinates from column number n in the data file. Column separators are any white space. Nonnumeric data causes the program to abort read operation and issue an error message. "xc 0" means use the index of the data in the file as the x coordinate (the tenth line's x coord is ten, etc.). &yc yc n Take data for the y coordinates from column number n in the data file. Column separators are any white space. Nonnumeric data causes the program to abort read operation and issue an error message. "yc 0" means use the index of the data in the file as the y coordinate (the tenth line's y coord is ten, etc.). &xsixty xsixty n Take data for the x coordinates from column number n in the data file. Column separators are any white space. Nonnumeric data causes the program to abort read operation and issue an error message. &pc pc n Take data for the p coordinates from column number n in the data file. Column separators are any white space. Nonnumeric data causes the program to abort read operation and issue an error message. &ec ec n Take data for the e coordinates from column number n in the data file. Column separators are any white space. Nonnumeric data causes the program to abort read operation and issue an error message. &limits limits [ x1 x2 y1 y2 ] If four arguments are present, set the limits of the plot to the given values: the x values range from x1 to x2 and the y values from y1 to y2. If a '*' is substituted for an argument the extreme value is used. If a '-' is substituded for an argument the previous value is used. If no arguments are given, set the limits to the extremes of the data values so that all points appear in the plot. &quit quit Exit the program, clear the screen, and set the window back to the initial size. "exit" and "end" are synonyms. &spawn spawn Exit the program, but leave the graphics window present on the display and leave its process alive. The user can continue to click the mouse while inside the graphics window to get positions. The user must eventually kill the process associated with the graphics window, either with a "kill" command to the shell, or via his window manager's "Delete Window" command. &input input filename Run commands from an ASCII file "filename". "filename" may be produced by the save command or from an editor. Each line of the file contains one command, followed by any arguments. Any syntax error in file will result in an error message and causes the sequence of commands to terminate. &save save filename Save commands in an ASCII file "filename" in the current directory. All subsequent commands issued will be echoed into the file, one command per line. Any command with syntax error will not be echoed, but commands which are syntactically correct but nonetheless cause other errors will be echoed into the file. Save can be terminated by the nosave command. &nosave nosave Terminate save. The save file is closed. &clear clear Clear the graphing area of the screen. &points points Place the current point markers at each one of the data points which are within the boundaries of the screen. &connect connect [delay] Draw lines connecting the current data points, clipping lines to the off-screen points at the plot boundaries, using the line type selected by ltype. If an optional number is specified it delays that number of tenths of a second between drawing each line. &box box [ xscale yscale ] Draw a box around the plot area, and then tick mark the x and the y axes. The axes are labeled with values of the of the variables in scientific notation. If arguments xscale and yscale are given, these values are used to scale the tick marks. If no arguments are given, then the program will automatically scale the axes with appropriate values. &xlabel xlabel label Place the text string "label", which can be more than one word, horizontally below the x axis. &ylabel ylabel label Place the text string "label", which can be more than one word, vertically to the left of the y axis, reading downwards. &title title label Place the string "label", which can be more than one word, centered above the graph. &relocate relocate [ xp yp ] Position the text cursor to the location (xp, yp) on the graph. Both xp and yp must be in current graph coordinates. If no arguments are given, report the current text position. &cursor cursor Use the mouse to get the coordinates of the point to which the cursor is pointing. The left button causes the coordinates of that point to be typed in the text window and sets the current text position to them; this can be done several times in succession if desired. The right button stops cursor input. &label label text Place the string "text", which may be more than one word, at the current text position on the graph. If the current text position is not inside the plot boundaries, ignore the command. &draw draw xp yp Draws a line from the current text position on the graph to the point (xp, yp). It then updates the current text position. &plot plot file Does the following (very common combo) in order 1. data "file" 2. xc 1 3. yc 2 4. limits 5. box 6. connect &hist hist Draws the values read in the xcolumn and ycolumn pairs with horizontal lines used typically to display histograms, instead of directly like the connect command. &vfield vfield Draws a field of vectors with their tails placed in the x, y values and of length derived from the pc coordinate and at an angle in degrees CCW from the right found in the ec coordinate. The scale of the length can be adjusted by the 'expand' command. &errorbar errorbar K Draws an error bar from the x,y location of length specified in the 'ec coordinate, and at an angle 90*(K-1) CCW from the x-axis. &erase erase Cleare the graphics screen. &end end Exit the program, clear the screen, and set the window back to the initial size. "exit" and "quit" are synonyms. &exit exit Exit the program, clear the screen, and set the window back to the initial size. "end" and "quit" are synonyms. &xlog xlog Replaces the data in the x-column with the 10 base logarithm. If the data are less than or equal to zero, the data are replaced with -50. &ylog ylog Replaces the data in the y-column with the 10 base logarithm. If the data are less than or equal to zero, the data are replaced with -50. &dot dot Places a marker (defined by ptype) at the current position as defined by relocate. &wait wait N wait data wait If given an integer argument N, waits for N seconds, then continues. If argument is the string "data", waits until the current data file changes, then continues. If argument is anything else, interpreted as the name of a file containing XPLOT commands. Waits until that file is modified, then executes the commands therein. &begin begin Used with the loop to demarcate the start of an infinite loop. It can only be used in the file command mode. &loop begin Used with the begin to end the loop.