Provided by: feedgnuplot_1.51-1_all bug


       feedgnuplot - General purpose pipe-oriented plotting tool


       Simple plotting of piped data:

        $ seq 5 | awk '{print 2*$1, $1*$1}'
        2 1
        4 4
        6 9
        8 16
        10 25

        $ seq 5 | awk '{print 2*$1, $1*$1}' |
          feedgnuplot --lines --points --legend 0 "data 0" --title "Test plot" --y2 1
                      --unset grid --terminal 'dumb 80,40' --exit

                                         Test plot

         10 +-----------------------------------------------------------------+ 25
            |       +        +       +       +       +        +       +    *##|
            |                                                  data 0 ***A*#* |
            |                                                          ** #   |
          9 |-+                                                      ** ##    |
            |                                                      **  #      |
            |                                                    **   #       |
            |                                                  **   ##      +-| 20
          8 |-+                                               A    #          |
            |                                               **    #           |
            |                                             **    ##            |
            |                                           **     #              |
            |                                         **      B               |
          7 |-+                                     **      ##                |
            |                                     **      ##                +-| 15
            |                                   **       #                    |
            |                                 **       ##                     |
          6 |-+                             *A       ##                       |
            |                             **       ##                         |
            |                           **        #                           |
            |                         **        ##                          +-| 10
          5 |-+                     **        ##                              |
            |                     **        #B                                |
            |                   **        ##                                  |
            |                 **        ##                                    |
          4 |-+              A       ###                                      |
            |              **      ##                                         |
            |            **      ##                                         +-| 5
            |          **      ##                                             |
            |        **    ##B#                                               |
          3 |-+    **  ####                                                   |
            |    **####                                                       |
            |  ####                                                           |
            |##     +        +       +       +       +        +       +       |
          2 +-----------------------------------------------------------------+ 0
            1      1.5       2      2.5      3      3.5       4      4.5      5

       Simple real-time plotting example: plot how much data is received on the wlan0 network
       interface in bytes/second (uses bash, awk and Linux):

        $ while true; do sleep 1; cat /proc/net/dev; done |
          gawk '/wlan0/ {if(b) {print $2-b; fflush()} b=$2}' |
          feedgnuplot --lines --stream --xlen 10 --ylabel 'Bytes/sec' --xlabel seconds


       This is a flexible, command-line-oriented frontend to Gnuplot. It creates plots from data
       coming in on STDIN or given in a filename passed on the commandline. Various data
       representations are supported, as is hardcopy output and streaming display of live data. A
       simple example:

        $ seq 5 | awk '{print 2*$1, $1*$1}' | feedgnuplot

       You should see a plot with two curves. The "awk" command generates some data to plot and
       the "feedgnuplot" reads it in from STDIN and generates the plot. The "awk" invocation is
       just an example; more interesting things would be plotted in normal usage. No commandline-
       options are required for the most basic plotting. Input parsing is flexible; every line
       need not have the same number of points. New curves will be created as needed.

       The most commonly used functionality of gnuplot is supported directly by the script.
       Anything not directly supported can still be done with options such as "--set",
       "--extracmds" "--style", etc. Arbitrary gnuplot commands can be passed in with
       "--extracmds". For example, to turn off the grid, you can pass in "--extracmds 'unset
       grid'". Commands "--set" and "--unset" exists to provide nicer syntax, so this is
       equivalent to passing "--unset grid". As many of these options as needed can be passed in.
       To add arbitrary curve styles, use "--style curveID extrastyle". Pass these more than once
       to affect more than one curve.

       To apply an extra style to all the curves that lack an explicit "--style", pass in
       "--styleall extrastyle". In the most common case, the extra style is "with something". To
       support this more simply, you can pass in "--with something" instead of "--styleall 'with
       something'". "--styleall" and "--with" are mutually exclusive. Furthermore any curve-
       specific "--style" overrides the global "--styleall" or "--with" setting.

   Data formats
       By default, each value present in the incoming data represents a distinct data point, as
       demonstrated in the original example above (we had 10 numbers in the input and 10 points
       in the plot). If requested, the script supports more sophisticated interpretation of input

       Domain selection

       If "--domain" is passed in, the first value on each line of input is interpreted as the
       X-value for the rest of the data on that line. Without "--domain" the X-value is the line
       number, and the first value on a line is a plain data point like the others. Default is
       "--nodomain". Thus the original example above produces 2 curves, with 1,2,3,4,5 as the
       X-values. If we run the same command with "--domain":

        $ seq 5 | awk '{print 2*$1, $1*$1}' | feedgnuplot --domain

       we get only 1 curve, with 2,4,6,8,10 as the X-values. As many points as desired can appear
       on a single line, but all points on a line are associated with the X-value at the start of
       that line.

       Curve indexing

       We index the curves in one of 3 ways: sequentially, explicitly with a "--dataid" or by
       "--vnlog" headers.

       By default, each column represents a separate curve. The first column (after any domain)
       is curve 0. The next one is curve 1 and so on. This is fine unless sparse data is to be
       plotted. With the "--dataid" option, each point is represented by 2 values: a string
       identifying the curve, and the value itself.  If we add "--dataid" to the original

        $ seq 5 | awk '{print 2*$1, $1*$1}' | feedgnuplot --dataid --autolegend

       we get 5 different curves with one point in each. The first column, as produced by "awk",
       is 2,4,6,8,10. These are interpreted as the IDs of the curves to be plotted.

       If we're plotting "vnlog" data (<>) then we can get the
       curve IDs from the vnlog header. Vnlog is a trivial data format where lines starting with
       "#" are comments and the first comment contains column labels. If we have such data,
       "feedgnuplot --vnlog" can interpret these column labels if the "vnlog" perl modules are

       The "--autolegend" option adds a legend using the given IDs to label the curves. The IDs
       need not be numbers; generic strings are accepted. As many points as desired can appear on
       a single line. "--domain" can be used in conjunction with "--dataid" or "--vnlog".

       Multi-value style support

       Depending on how gnuplot is plotting the data, more than one value may be needed to
       represent the range of a single point. Basic 2D plots have 2 numbers representing each
       point: 1 domain and 1 range. But if plotting with "--circles", for instance, then there's
       an extra range value: the radius. Many other gnuplot styles require more data: errorbars,
       variable colors ("with points palette"), variable sizes ("with points ps variable"),
       labels and so on.  The feedgnuplot tool itself does not know about all these intricacies,
       but they can still be used, by specifying the specific style with "--style", and
       specifying how many values are needed for each point with any of "--rangesizeall",
       "--tuplesizeall", "--rangesize", "--tuplesize". These options are required only for styles
       not explicitly supported by feedgnuplot; supported styles do the right thing

       Specific example: if making a 2d plot of y error bars, the exact format can be queried by
       running "gnuplot" and invoking "help yerrorbars". This tells us that there's a 3-column
       form: "x y ydelta" and a 4-column form: "x y ylow yhigh". With 2d plots feedgnuplot will
       always output the 1-value domain "x", so the rangesize is 2 and 3 respectively. Thus the
       following are equivalent:

        $ echo '1 2 0.3
                2 3 0.4
                3 4 0.5' | feedgnuplot --domain --rangesizeall 2 --with 'yerrorbars'

        $ echo '1 2 0.3
                2 3 0.4
                3 4 0.5' | feedgnuplot --domain --tuplesizeall 3 --with 'yerrorbars'

        $ echo '1 2 1.7 2.3
                2 3 2.6 3.4
                3 4 3.5 4.5' | feedgnuplot --domain --rangesizeall 3 --with 'yerrorbars'

       3D data

       To plot 3D data, pass in "--3d". "--domain" MUST be given when plotting 3D data to avoid
       domain ambiguity. If 3D data is being plotted, there are by definition 2 domain values
       instead of one (Z as a function of X and Y instead of Y as a function of X). Thus the
       first 2 values on each line are interpreted as the domain instead of just 1. The rest of
       the processing happens the same way as before.

       Time/date data

       If the input data domain is a time/date, this can be interpreted with "--timefmt". This
       option takes a single argument: the format to use to parse the data. The format is
       documented in 'set timefmt' in gnuplot, although the common flags that "strftime"
       understands are generally supported. The backslash sequences in the format are not
       supported, so if you want a tab, put in a tab instead of \t. Whitespace in the format is
       supported. When this flag is given, some other options act a little bit differently:

       ·   "--xlen" is an integer in seconds

       ·   "--xmin" and "--xmax" must use the format passed in to "--timefmt"

       Using this option changes both the way the input is parsed and the way the x-axis tics are
       labelled. Gnuplot tries to be intelligent in this labelling, but it doesn't always do what
       the user wants. The labelling can be controlled with the gnuplot "set format" command,
       which takes the same type of format string as "--timefmt". Example:

        $ sar 1 -1 |
          awk '$1 ~ /..:..:../ && $8 ~/^[0-9\.]*$/ {print $1,$8; fflush()}' |
          feedgnuplot --stream --domain
                       --lines --timefmt '%H:%M:%S'
                       --set 'format x "%H:%M:%S"'

       This plots the 'idle' CPU consumption against time.

       Note that while gnuplot supports the time/date on any axis, feedgnuplot currently supports
       it only as the x-axis domain. This may change in the future.

   Real-time streaming data
       To plot real-time data, pass in the "--stream [refreshperiod]" option. Data will then be
       plotted as it is received. The plot will be updated every "refreshperiod" seconds. If the
       period isn't specified, a 1Hz refresh rate is used. To refresh at specific intervals
       indicated by the data, set the refreshperiod to 0 or to 'trigger'. The plot will then only
       be refreshed when a data line 'replot' is received. This 'replot' command works in both
       triggered and timed modes, but in triggered mode, it's the only way to replot. Look in
       "Special data commands" for more information.

       To plot only the most recent data (instead of all the data), "--xlen windowsize" can be
       given. This will create an constantly-updating, scrolling view of the recent past.
       "windowsize" should be replaced by the desired length of the domain window to plot, in
       domain units (passed-in values if "--domain" or line numbers otherwise). If the domain is
       a time/date via "--timefmt", then "windowsize" is and integer in seconds. If we're
       plotting a histogram, then "--xlen" causes a histogram over a moving window to be
       computed. The subtlely here is that with a histogram you don't actually see the domain
       since only the range is analyzed. But the domain is still there, and can be utilized with
       "--xlen". With "--xlen" we can plot only histograms or only non-histograms.

       Special data commands

       If we are reading streaming data, the input stream can contain special commands in
       addition to the raw data. Feedgnuplot looks for these at the start of every input line. If
       a command is detected, the rest of the line is discarded. These commands are

           This command refreshes the plot right now, instead of waiting for the next refresh
           time indicated by the timer. This command works in addition to the timed refresh, as
           indicated by "--stream [refreshperiod]".

           This command clears out the current data in the plot. The plotting process continues,
           however, to any data following the "clear".

           This command causes feedgnuplot to exit.

   Hardcopy output
       The script is able to produce hardcopy output with "--hardcopy outputfile". The output
       type can be inferred from the filename, if .ps, .eps, .pdf, .svg, .png or .gp is
       requested. If any other file type is requested, "--terminal" must be passed in to tell
       gnuplot how to make the plot. If "--terminal" is passed in, then the "--hardcopy" argument
       only provides the output filename.

       The .gp output is special. Instead of asking gnuplot to plot to a particular terminal,
       writing to a .gp simply dumps a self-executable gnuplot script into the given file. This
       is similar to what "--dump" does, but writes to a file, and makes sure that the file can
       be self-executing.

   Self-plotting data files
       This script can be used to enable self-plotting data files. There are several ways of
       doing this: with a shebang (#!) or with inline perl data.

       Self-plotting data with a #!

       A self-plotting, executable data file "data" is formatted as

        $ cat data
        #!/usr/bin/feedgnuplot --lines --points
        2 1
        4 4
        6 9
        8 16
        10 25
        12 36
        14 49
        16 64
        18 81
        20 100
        22 121
        24 144
        26 169
        28 196
        30 225

       This is the shebang (#!) line followed by the data, formatted as before. The data file can
       be plotted simply with

        $ ./data

       The caveats here are that on Linux the whole #! line is limited to 127 characters and that
       the full path to feedgnuplot must be given. The 127 character limit is a serious
       limitation, but this can likely be resolved with a kernel patch. I have only tried on
       Linux 2.6.

       Self-plotting data with gnuplot

       Running "feedgnuplot --hardcopy ...." will create a self-executable gnuplot
       script in ""

       Self-plotting data with perl inline data

       Perl supports storing data and code in the same file. This can also be used to create
       self-plotting files:

        $ cat
        use strict;
        use warnings;

        open PLOT, "| feedgnuplot --lines --points" or die "Couldn't open plotting pipe";
        while( <DATA> )
          my @xy = split;
          print PLOT "@xy\n";
        2 1
        4 4
        6 9
        8 16
        10 25
        12 36
        14 49
        16 64
        18 81
        20 100
        22 121
        24 144
        26 169
        28 196
        30 225

       This is especially useful if the logged data is not in a format directly supported by
       feedgnuplot. Raw data can be stored after the __DATA__ directive, with a small perl script
       to manipulate the data into a useable format and send it to the plotter.


       ·   --"[no]domain"

           If enabled, the first element of each line is the domain variable. If not, the point
           index is used

       ·   --"[no]dataid"

           If enabled, each data point is preceded by the ID of the data set that point
           corresponds to. This ID is interpreted as a string, NOT as just a number. If not
           enabled, the order of the point is used.

           As an example, if line 3 of the input is "0 9 1 20" then

           ·   "--nodomain --nodataid" would parse the 4 numbers as points in 4 different curves
               at x=3

           ·   "--domain --nodataid" would parse the 4 numbers as points in 3 different curves at
               x=0. Here, 0 is the x-variable and 9,1,20 are the data values

           ·   "--nodomain --dataid" would parse the 4 numbers as points in 2 different curves at
               x=3. Here 0 and 1 are the data IDs and 9 and 20 are the data values

           ·   "--domain --dataid" would parse the 4 numbers as a single point at x=0. Here 9 is
               the data ID and 1 is the data value. 20 is an extra value, so it is ignored. If
               another value followed 20, we'd get another point in curve ID 20

       ·   "--vnlog"

           Vnlog is a trivial data format where lines starting with "#" are comments and the
           first comment contains column labels. Some tools for working with such data are
           available from the "vnlog" project: <>.  With the
           "vnlog" perl modules installed, we can read the vnlog column headers with "feedgnuplot
           --vnlog". This replaces "--dataid", and we can do all the normal things with these
           headers. For instance "feedgnuplot --vnlog --autolegend" will generate plot legends
           for each column in the vnlog, using the vnlog column label in the legend.

       ·   "--[no]3d"

           Do [not] plot in 3D. This only makes sense with "--domain". Each domain here is an
           (x,y) tuple

       ·   --"timefmt [format]"

           Interpret the X data as a time/date, parsed with the given format

       ·   "--colormap"

           Show a colormapped xy plot. Requires extra data for the color. zmin/zmax can be used
           to set the extents of the colors. Automatically sets the "--rangesize"/"--tuplesize".

       ·   "--stream [period]"

           Plot the data as it comes in, in realtime. If period is given, replot every period
           seconds. If no period is given, replot at 1Hz. If the period is given as 0 or
           'trigger', replot only when the incoming data dictates this. See the "Real-time
           streaming data" section of the man page.

       ·   "--[no]lines"

           Do [not] draw lines to connect consecutive points

       ·   "--[no]points"

           Do [not] draw points

       ·   "--circles"

           Plot with circles. This requires a radius be specified for each point.  Automatically
           sets the "--rangesize"/"--tuplesize". "Not" supported for 3d plots.

       ·   "--title xxx"

           Set the title of the plot

       ·   "--legend curveID legend"

           Set the label for a curve plot. Use this option multiple times for multiple curves.
           With "--dataid", curveID is the ID. Otherwise, it's the index of the curve, starting
           at 0

       ·   "--autolegend"

           Use the curve IDs for the legend. Titles given with "--legend" override these

       ·   "--xlen xxx"

           When using "--stream", sets the size of the x-window to plot. Omit this or set it to 0
           to plot ALL the data. Does not make sense with 3d plots. Implies "--monotonic". If
           we're plotting a histogram, then "--xlen" causes a histogram over a moving window to
           be computed. The subtlely here is that with a histogram you don't actually see the
           domain since only the range is analyzed. But the domain is still there, and can be
           utilized with "--xlen". With "--xlen" we can plot only histograms or only

       ·   "--xmin/xmax/ymin/ymax/y2min/y2max/zmin/zmax xxx"

           Set the range for the given axis. These x-axis bounds are ignored in a streaming plot.
           The y2-axis bound do not apply in 3d plots. The z-axis bounds apply only to 3d plots
           or colormaps. Note that there is no "--xrange" to set both sides at once or "--xinv"
           to flip the axis around: anything more than the basics supported in this option is
           clearly obtainable by talking to gnuplot, for instance "--set 'xrange [20:10]'" to set
           the given inverted bounds.

       ·   "--xlabel/ylabel/y2label/zlabel xxx"

           Label the given axis. The y2-axis label does not apply to 3d plots while the z-axis
           label applies only to 3d plots.

       ·   "--y2 xxx"

           Plot the data specified by this curve ID on the y2 axis. Without "--dataid", the ID is
           just an ordered 0-based index. Does not apply to 3d plots. Can be passed multiple
           times, or passed a comma-separated list. By default the y2-axis curves look the same
           as the y-axis ones. I.e. the viewer of the resulting plot has to be told which is
           which via an axes label, legend, etc. Prior to version 1.25 of feedgnuplot the curves
           plotted on the y2 axis were drawn with a thicker line. This is no longer the case, but
           that behavior can be brought back by passing something like

            --y2 curveid --style curveid 'linewidth 3'

       ·   "--histogram curveID"

           Set up a this specific curve to plot a histogram. The bin width is given with the
           "--binwidth" option (assumed 1.0 if omitted). If a drawing style is not specified for
           this curve ("--curvestyle") or all curves ("--with", "--curvestyleall") then the
           default histogram style is set: filled boxes with borders. This is what the user
           generally wants. This works with "--domain" and/or "--stream", but in those cases the
           x-value is used only to cull old data because of "--xlen" or "--monotonic". I.e. the
           domain values are not drawn in any way. Can be passed multiple times, or passed a
           comma- separated list

       ·   "--binwidth width"

           The width of bins when making histograms. This setting applies to ALL histograms in
           the plot. Defaults to 1.0 if not given.

       ·   "--histstyle style"

           Normally, histograms are generated with the 'smooth frequency' gnuplot style.
           "--histstyle" can be used to select different "smooth" settings (see the gnuplot "help
           smooth" page for more info). Allowed values are 'frequency' (the default), 'fnormal'
           (available in very recent gnuplots), 'unique', 'cumulative' and 'cnormal'. 'fnormal'
           is a normalized histogram. 'unique' indicates whether a bin has at least one item in
           it: instead of counting the items, it'll always report 0 or 1. 'cumulative' is the
           integral of the 'frequency' histogram.  'cnormal' is like 'cumulative', but rescaled
           to end up at 1.0.

       ·   "--style curveID style"

           Additional styles per curve. With "--dataid", curveID is the ID. Otherwise, it's the
           index of the curve, starting at 0. curveID can be a comma-separated list of IDs to
           which the given style should apply. Use this option multiple times for multiple
           curves. "--styleall" does not apply to curves that have a "--style".

       ·   "--curvestyle curveID"

           Synonym for "--style"

       ·   "--styleall xxx"

           Additional styles for all curves that have no "--style". This is overridden by any
           applicable "--style". Exclusive with "--with".

       ·   "--curvestyleall xxx"

           Synonym for "--styleall"

       ·   "--with xxx"

           Same as "--styleall", but prefixed with "with". Thus

            --with boxes

           is equivalent to

            --styleall 'with boxes'

           Exclusive with "--styleall".

       ·   "--extracmds xxx"

           Additional commands to pass on to gnuplot verbatim. These could contain extra global
           styles for instance. Can be passed multiple times.

       ·   "--set xxx"

           Additional 'set' commands to pass on to gnuplot verbatim. "--set 'a b c'" will result
           in gnuplot seeing a "set a b c" command. Can be passed multiple times.

       ·   "--unset xxx"

           Additional 'unset' commands to pass on to gnuplot verbatim. "--unset 'a b c'" will
           result in gnuplot seeing a "unset a b c" command. Can be passed multiple times.

       ·   "--image filename"

           Overlays the data on top of a raster image given in "filename". This is passed through
           to gnuplot via "--equation", and is not interpreted by "feedgnuplot" other than
           checking for existence. Usually images have their origin at the top-left corner, while
           plots have it in the bottom-left corner instead. Thus if the y-axis extents are not
           specified ("--ymin", "--ymax", "--set 'yrange ...'") this option will also flip around
           the y axis to make the image appear properly. Since this option is just a passthrough
           to gnuplot, finer control can be achieved by passing in "--equation" and "--set yrange
           ..." directly.

           "--equation xxx"

           Gnuplot can plot both data and symbolic equations. "feedgnuplot" generally plots data,
           but with this option can plot symbolic equations also. This is generally intended to
           augment data plots, since for equation-only plots you don't need "feedgnuplot".
           "--equation" can be passed multiple times for multiple equations. The given strings
           are passed to gnuplot directly without anything added or removed, so styling and such
           should be applied in the string.  A basic example:

            seq 100 | awk '{print $1/10, $1/100}' |
              feedgnuplot --with 'lines lw 3' --domain --ymax 1
                          --equation 'sin(x)/x' --equation 'cos(x)/x with lines lw 4'

           Here I plot the incoming data (points along a line) with the given style (a line with
           thickness 3), and I plot two damped sinusoids on the same plot. The sinusoids are not
           affected by "feedgnuplot" styling, so their styles are set separately, as in this
           example. More complicated example:

            seq 360 | perl -nE '$th=$_/360 * 3.14*2; $c=cos($th); $s=sin($th); say "$c $s"' |
              feedgnuplot --domain --square
                          --set parametric --set "trange [0:2*3.14]" --equation "sin(t),cos(t)"

           Here the data I generate is points along the unit circle. I plot these as points, and
           I also plot a true circle as a parametric equation.

       ·   "--square"

           Plot data with aspect ratio 1. For 3D plots, this controls the aspect ratio for all 3

       ·   "--square_xy"

           For 3D plots, set square aspect ratio for ONLY the x,y axes

       ·   "--hardcopy xxx"

           If not streaming, output to a file specified here. Format inferred from filename,
           unless specified by "--terminal". If "--terminal" is given, "--hardcopy" sets only the
           output filename.

       ·   "--terminal xxx"

           String passed to 'set terminal'. No attempts are made to validate this.  "--hardcopy"
           sets this to some sensible defaults if "--hardcopy" is set to a filename ending in
           ".png", ".pdf", ".ps", ".eps" or ".svg". If any other file type is desired, use both
           "--hardcopy" and "--terminal"

       ·   "--maxcurves N"

           The maximum allowed number of curves. This is 100 by default, but can be reset with
           this option. This exists purely to prevent perl from allocating all of the system's
           memory when reading bogus data

       ·   "--monotonic"

           If "--domain" is given, checks to make sure that the x-coordinate in the input data is
           monotonically increasing. If a given x-variable is in the past, all data currently
           cached for this curve is purged. Without "--monotonic", all data is kept. Does not
           make sense with 3d plots. No "--monotonic" by default. The data is replotted before
           being purged. This is useful in streaming plots where the incoming data represents
           multiple iterations of the same process (repeated simulations of the same period in
           time, for instance).

       ·   "--rangesize curveID N"

           The options "--rangesizeall" and "--rangesize" set the number of values are needed to
           represent each point being plotted (see "Multi-value style support" above). These
           options are only needed if unknown styles are used, with "--styleall" or "--with" for

           "--rangesize" is used to set how many values are needed to represent the range of a
           point for a particular curve. This overrides any defaults that may exist for this
           curve only.

           With "--dataid", curveID is the ID. Otherwise, it's the index of the curve, starting
           at 0. curveID can be a comma-separated list of IDs to which the given rangesize should

       ·   "--tuplesize curveID N"

           Very similar to "--rangesize", but instead of specifying the range only, this
           specifies the whole tuple. For instance if we're plotting circles, the tuplesize is 3:
           "x,y,radius". In a 2D plot there's a 1-dimensional domain: "x", so the rangesize is 2:
           "y,radius". This dimensionality can be given either way.

       ·   "--rangesizeall N"

           Like "--rangesize", but applies to all the curves.

       ·   "--tuplesizeall N"

           Like "--tuplesize", but applies to all the curves.

       ·   "--dump"

           Instead of printing to gnuplot, print to STDOUT. Very useful for debugging. It is
           possible to send the output produced this way to gnuplot directly.

       ·   "--exit"

           This controls what happens when the input data is exhausted, or when some part of the
           "feedgnuplot" pipeline is killed. This option does different things depending on
           whether "--stream" is active, so read this closely.

           With interactive gnuplot terminals (qt, x11, wxt), the plot windows live in a separate
           process from the main "gnuplot" process. It is thus possible for the main "gnuplot"
           process to exit, while leaving the plot windows up (a caveat is that such decapitated
           windows aren't interactive). There are 3 possible states of the polotting pipeline:

           Alive: "feedgnuplot", "gnuplot" alive, plot window process alive, no shell prompt
           (shell busy with "feedgnuplot")
           Half-alive: "feedgnuplot", "gnuplot" dead, plot window process alive (but non-
           interactive), shell prompt available
           Dead: "feedgnuplot", "gnuplot" dead, plot window process dead, shell prompt available

           The possibilities are:

           No "--stream", all data read in
               no "--exit" (default)
                   Alive. Need to Ctrl-C to get back into the shell

                   Half-alive. Non-interactive prompt up, and the shell accepts new commands.
                   Without "--stream" the goal is to show a plot, so a Dead state would not be

           "--stream", all data read in or the "feedgnuplot" process terminated
               no "--exit" (default)
                   Alive. Need to Ctrl-C to get back into the shell. This means that when making
                   live plots, the first Ctrl-C kills the data feeding process, but leaves the
                   final plot up for inspection. A second Ctrl-C kills feedgnuplot as well.

                   Dead. No plot is shown, and the shell accepts new commands. With "--stream"
                   the goal is to show a plot as the data comes in, which we have been doing. Now
                   that we're done, we can clean up everything.

           Note that one usually invokes "feedgnuplot" as a part of a shell pipeline:

            $ write_data | feedgnuplot

           If the user terminates this pipeline with ^C, then all the processes in the pipeline
           receive SIGINT. This normally kills "feedgnuplot" and all its "gnuplot" children, and
           we let this happen unless "--stream" and no "--exit".  If "--stream" and no "--exit",
           then we ignore the first ^C. The data feeder dies, and we behave as if the input data
           was exhausted. A second ^C kills us also.

       ·   "--geometry"

           If using X11, specifies the size, position of the plot window

       ·   "--version"

           Print the version and exit


   Basic plotting of piped data
        $ seq 5 | awk '{print 2*$1, $1*$1}'
        2 1
        4 4
        6 9
        8 16
        10 25

        $ seq 5 | awk '{print 2*$1, $1*$1}' |
          feedgnuplot --lines --points --legend 0 "data 0" --title "Test plot" --y2 1

   Realtime plot of network throughput
       Looks at wlan0 on Linux.

        $ while true; do sleep 1; cat /proc/net/dev; done |
          gawk '/wlan0/ {if(b) {print $2-b; fflush()} b=$2}' |
          feedgnuplot --lines --stream --xlen 10 --ylabel 'Bytes/sec' --xlabel seconds

   Realtime plot of battery charge in respect to time
       Uses the result of the "acpi" command.

        $ while true; do acpi; sleep 15; done |
          perl -nE 'BEGIN{ $| = 1; } /([0-9]*)%/; say join(" ", time(), $1);' |
          feedgnuplot --stream --ymin 0 --ymax 100 --lines --domain --xlabel 'Time' --timefmt '%s' --ylabel "Battery charge (%)"

   Realtime plot of temperatures in an IBM Thinkpad
       Uses "/proc/acpi/ibm/thermal", which reports temperatures at various locations in a

        $ while true; do cat /proc/acpi/ibm/thermal | awk '{$1=""; print}' ; sleep 1; done |
          feedgnuplot --stream --xlen 100 --lines --autolegend --ymax 100 --ymin 20 --ylabel 'Temperature (deg C)'

   Plotting a histogram of file sizes in a directory, granular to 10MB
        $ ls -l | awk '{print $5/1e6}' |
          feedgnuplot --histogram 0
            --binwidth 10
            --ymin 0 --xlabel 'File size (MB)' --ylabel Frequency

   Plotting a live histogram of the ping round-trip times for the past 20 seconds
        $ ping -A -D |
          perl -anE 'BEGIN { $| = 1; }
                     $F[0] =~ s/[\[\]]//g or next;
                     $F[7] =~ s/.*=//g    or next;
                     say "$F[0] $F[7]"' |
          feedgnuplot --stream --domain --histogram 0 --binwidth 10 \
                      --xlabel 'Ping round-trip time (s)'  \
                      --ylabel Frequency --xlen 20

   Plotting points on top of an existing image
       This can be done with "--image":

        $ <
          feedgnuplot --points --domain --image "image.png"

       or with "--equation":

        $ <
          feedgnuplot --points --domain
            --equation '"image.png" binary filetype=auto flipy with rgbimage'
            --set 'yrange [:] reverse'

       The "--image" invocation is a convenience wrapper for the "--equation" version. Finer
       control is available with "--equation".

       Here an existing image is given to gnuplot verbatim, and data to plot on top of it is
       interpreted by feedgnuplot as usual. "flipy" is useful here because usually the y axis
       points up, but when looking at images, this is usually reversed: the origin is the top-
       left pixel.


       This program is originally based on the script from Thanassis Tsiodras.
       It is available from his site at




       Dima Kogan, "<>"


       Copyright 2011-2012 Dima Kogan.

       This program is free software; you can redistribute it and/or modify it under the terms of
       either: the GNU General Public License as published by the Free Software Foundation; or
       the Artistic License.

       See for more information.