FEEDGNUPLOT(1)
okay bestie, welcome to the manual for feedgnuplot(1) — it's from the User Contributed Perl Documentation section, and it's literally the moment. let's get into it 💅
✨ NAME ✨
feedgnuplot — General purpose pipe-oriented plotting tool 🌈
💖 SYNOPSIS 💖
Simple plotting of piped data:
$ seq 5 | awk '{print 2*$1, $1*$1}'
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$ seq 5 | awk '{print 2*$1, $1*$1}' |
feedgnuplot \
--terminal 'dumb 80,40' --exit \
--lines \
--points \
--title "Test plot" \
--y2 1 \
--unset key \
--unset gridand you get this absolute masterpiece:
Test plot
10 +-----------------------------------------------------------------+ 25
| + + + + + + + ##*|
| ##* |
| ## * |
9 |-+ ## ** |
| ## * |
| ## * |
| ## ** +-| 20
8 |-+ B * |
| ## * |
| ## ** |
| ## * |
| ## A |
7 |-+ ## ** |
| ## ** +-| 15
| ## * |
| ## ** |
6 |-+ #B ** |
| ## ** |
| ## * |
| ## ** +-| 10
5 |-+ ## ** |
| ## *A |
| ## ** |
| ## ** |
4 |-+ B *** |
| ## ** |
| ## ** +-| 5
| ## ** |
| ## **A* |
3 |-+ ## **** |
| ##**** |
| ##** |
|## + + + + + + + |
2 +-----------------------------------------------------------------+ 0
1 1.5 2 2.5 3 3.5 4 4.5 5Simple real-time plotting example: plot how much data is received on the wlan0 network interface in bytes/second. This plot updates at 1Hz, and shows the last 10sec of history. The plot shown here is the final state of a sample run
$ while true; do
sleep 1;
cat /proc/net/dev;
done \
| gawk '/wlan0/ {if(b) {print $2-b; N++; fflush()} b=$2} N==15 {exit}' \
| feedgnuplot \
--terminal 'dumb 80,40' --exit \
--lines \
--title "wlan0 throughput" \
--stream \
--xlen 10 \
--ylabel 'Bytes/sec' \
--xlabel seconds \
--unset key \
--unset gridwhich gives you this gorgeous live view:
wlan0 throughput
300000 +---------------------------------------------------------------+
| + + + + + |
| |
| |
| * |
250000 |-+ * +-|
| ** |
| * * |
| * * |
| * * |
| * * |
200000 |-+ * * +-|
| * * |
| * * |
| * * |
| * * |
150000 |-+ * *+-|
| * * |
| * * |
| * * |
| * * |
| * * |
100000 |-+ * *-|
| * * |
| * *|
| ** * *|
| *** * * *|
50000 |-+ *** * **** * +*|
| ** ** ***** ** * |
| ** * *** ** * |
| ***** * ***** ** |
|** *** |
| + + + + + |
0 +---------------------------------------------------------------+
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seconds🦋 DESCRIPTION 🦋
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. For a tutorial and a gallery please see the guide at <https://github.com/dkogan/feedgnuplot/blob/master/guide/guide.org>
A simple example:
$ seq 5 | awk '{print 2*$1, $1*$1}' | feedgnuplotYou 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, --cmds --style, etc. Arbitrary gnuplot commands can be passed in with --cmds. For example, to turn off the grid, you can pass in --cmds '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 data
🌟 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 --domainwe 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 example:
$ seq 5 | awk '{print 2*$1, $1*$1}' | feedgnuplot --dataid --autolegendwe 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 (<https://www.github.com/dkogan/vnlog>) 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 available.
Okay so --autolegend literally just slaps a legend on there using whatever IDs you hand it to label the curves. And bestie, those IDs don't have to be numbers at all — generic strings are fully accepted, no cap. You can put as many points as you want on a single line. Oh and --domain can be used together with --dataid or --vnlog. Slay.
✨ Multi-value style support ✨
So here's the tea 🍵: depending on how gnuplot is plotting your data, you might need more than one value to represent the range of a single point. Basic 2D plots? Two numbers per point: 1 domain and 1 range. Cute. Simple. But if you're plotting with --circles, for instance, there's an extra range value: the radius. And so many other gnuplot styles need extra data too — errorbars, variable colors (with points palette), variable sizes (with points ps variable), labels, and on and on.
The feedgnuplot tool itself does not know about all these intricacies, but you can still use them! How? 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 <em>only</em> for styles that feedgnuplot doesn't explicitly support — the supported styles just do the right thing automatically. Iconic behavior, honestly. 👑
Specific example time, because I know you love one: if you're making a 2d plot of y error bars, the exact format can be queried by running gnuplot and invoking help yerrorbars. That tells us 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. So these are all literally 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. And --domain MUST be given when plotting 3D data to avoid domain ambiguity. Periodt.
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. So the first 2 values on each line get interpreted as the domain instead of just 1. Everything after that? Same processing as before. Easy. 💅
🌸 Time/date data 🌸
If your input data domain is a time/date, you can interpret it 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 an actual tab instead of \t. Whitespace in the format is supported. 🎀
When this flag is given, some other options act a little bit differently:
--xlenand--binwidthare integers in seconds--xminand--xmaxmust 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 (ngl, relatable). 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.
💜 'using' expressions 💜
We just described how feedgnuplot parses its input data. So now, when passing this data to gnuplot, each curve is sent independently. The domain appears in the leading columns followed by --rangesize columns to complete each row. Without --domain, feedgnuplot explicitly writes out sequential integers. Then gnuplot knows how many values it has for each point, and it knows which style we're using, so it's able to interpret the data appropriately, and to make the correct plot. Bestie teamwork. 🫶
As an example: if gnuplot is passed 2 columns of data, and it's plotting with points, it will use column 1 for the x coordinate and column 2 for the y coordinate. This is the default behavior, but the meaning of each column can be controlled via a using expression in gnuplot (not feedgnuplot; keep reading).
The default is sequential integers, so this example uses using 1:2 by default. We can flip the meaning of the columns by passing using 2:1. Arbitrary expressions may be specified by enclosing each field in (), and using $ to denote each data column. So to use the 2nd column as the x coordinate and the sum of the two columns as the y coordinate, using 2:($1+$2) is passed.
Furthermore, the number of columns can vary. For instance gnuplot can read the same two columns of data, but produce a plot with the extra column encoding the sum as the color: using 1:2:($1+$2) with points palette. Please see the gnuplot documentation for lots of detail. 📚
That's how gnuplot works. Most of the time, feedgnuplot doesn't pass any using expressions at all, and gnuplot does the default thing. But if we want to do something fancy, feedgnuplot supports --using curveID expression and --usingall expression. So we can plot a parabola:
seq 100 | feedgnuplot --lines --usingall '1:($2*$2)'This is powerful, but there are some things to keep in mind:
--usingoverrides whateverusingexpression feedgnuplot was going to pass. feedgnuplot passes ausingexpression only if--histogramor--timefmtor--xticlabelsare given. So if--usingis given together with any of these, the user must take care to do the right thing (whatever that means at that time). 😭- The
--tuplesizecontrols the data passed to feedgnuplot and the data then passed to gnuplot. It does not directly control how gnuplot eventually interprets the data:--usingdoes that. So for instance we can plot color-coded points:
seq 10 | feedgnuplot --with 'points pt 7 palette' --usingall '1:2:2'Here feedgnuplot read 1 column of data. It defauled to --tuplesize 2, so it passed 2 columns of data to gnuplot. gnuplot then produced 3 values for each point, and plotted them as indicated with the points palette style. ✨
- You always need a column of data to generate a curve. You might want to use a
usingexpression to plot a time series and its cumulative integral. Theusingexpression can compute the integral, but you must pass in the data twice; once for each curve to plot:
seq 100 | \
awk '{print $1,$1}' | \
feedgnuplot \
--cmds 'sum=0' \
--cmds 'accum(x) = (sum=sum+x)' \
--using 1 '1:(accum($2))' \
--lines --y2 1🎀 Real-time streaming data 🎀
To plot real-time data, pass in the --stream [refreshperiod] option. Data will then be plotted as it's received, live, main character energy only. The plot gets 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. Choose your fighter. 🥊
🍓 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:
replot— 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].clear— This command clears out the current data in the plot. The plotting process continues, however, to any data following theclear.exit— 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. So extra. 💅
🌈 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
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30 225This is the shebang (#!) line followed by the data, formatted as before. The data file can be plotted simply with:
$ ./dataok so the lil caveats here bestie: on Linux the whole #! line is capped at 127 characters 💀 and you gotta give the full path to feedgnuplot. That 127-char limit is a serious limitation ngl, but it can likely be resolved with a kernel patch. (I have only tried on Linux 2.6, so like, ymmv.)
🌸 Self-plotting data with gnuplot 🌸
Running feedgnuplot --hardcopy plotdata.gp .... will create a self-executable gnuplot script in plotdata.gp ✨
🦋 Self-plotting data with perl inline data 🦋
Perl supports storing data and code in the same file — which is iconic actually, and can also be used to create self-plotting files:
$ cat plotdata.pl
#!/usr/bin/perl
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";
}
__DATA__
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30 225This 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 🫶
🎀 ARGUMENTS 🎀
--[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 --nodataidwould parse the 4 numbers as points in 4 different curves at x=3--domain --nodataidwould parse the 4 numbers as points in 3 different curves at x=0. Here,0is the x-variable and9,1,20are the data values--nodomain --dataidwould parse the 4 numbers as points in 2 different curves at x=3. Here0and1are the data IDs and9and20are the data values--domain --dataidwould parse the 4 numbers as a single point at x=0. Here9is the data ID and1is the data value.20is an extra value, so it is ignored. If another value followed20, 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 thevnlogproject: <https://www.github.com/dkogan/vnlog>. With thevnlogperl modules installed, we can read the vnlog column headers withfeedgnuplot --vnlog. This replaces--dataid, and we can do all the normal things with these headers. For instancefeedgnuplot --vnlog --autolegendwill 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— This is a legacy option used to show a colormapped xy plot. It does:- Adds
paletteto--curvestyleall - Adds 1 to the default
--tuplesize(if--tuplesizeallis not given) - Uses
--zmin,--zmaxto set the colorbar range
- Adds
It's clearer to set the relevant options explicitly, but --colormap still exists for compatibility.
--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 as0or'trigger', replot only when the incoming data dictates this. See theReal-time streaming datasection 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--legendoverride 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--xlencauses 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--xlenwe can plot only histograms or only non-histograms.--xmin/xmax/x2min/x2max/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 x2/y2-axis bounds do not apply in 3d plots. The z-axis bounds apply only to 3d plots or colormaps. Note that there is no--xrangeto set both sides at once or--xinvto 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/x2label/ylabel/y2label/zlabel/cblabel xxx— Label the given axis. The x2/y2-axis labels do not apply to 3d plots while the z-axis label applies only to 3d plots. Thecblabelapplies to the colorbar, if there is one.--x2/--y2/--x1y2/--x2y1/--x2y2 xxx— By default data is plotted against the x1 and y1 axes (the left and bottom one respectively). If we want a particular curve plotted against a different axis, we can specify that with these options. You pass--AXIS IDwhere AXIS defines the axis (x2ory2orx1y2orx2y1orx2y2) and the ID is the curve ID.--x2is a synonym for--x2y1and--y2is a synonym for--x1y2. The curve ID is an ordered 0-based index or a specific ID if--dataidor--vnlog. None of these apply to 3d plots. Can be passed multiple times for different curve IDs, multiple IDs can be passed in as a comma-separated list. By default the curves plotted against the various axes are not drawn in any differentiated way: the viewer of the resulting plot has to be told which is which via an axes label, legend, colors, etc. Prior to version 1.25 offeedgnuplotthe 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--binwidthoption (assumed1.0if 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--domainand/or--stream, but in those cases the x-value is used only to cull old data because of--xlenor--monotonic. I.e. the domain values are not drawn in any way. Can be passed multiple times, or passed a comma-separated list.--xticlabels— If given, the x-axis tic labels are not numerical, but are read from the data. This changes the interpretation of the input data: with--domain, each line begins withx label ..... Without--domain, each line begins withlabel .... Clearly, the labels may not contain whitespace. This does not affect the tuple size. This makes sense only without--3d. Please see the guide (<https://github.com/dkogan/feedgnuplot/blob/master/guide/guide.org>) for usage examples. 📖--binwidth width— The width of bins when making histograms. This setting applies to ALL histograms in the plot. Defaults to1.0if not given.--histstyle style— Normally, histograms are generated with the'smooth frequency'gnuplot style.--histstylecan be used to select differentsmoothsettings (see the gnuplothelp smoothpage 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.--stylealldoes 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 withwith. Thus
--with boxesis equivalent to
--styleall 'with boxes'Exclusive with --styleall.
--every curveID factor— Decimates the input. Instead of plotting every point in the given curve, plot one point per factor. This is useful to quickly process huge datasets. For instance, to plot 1% of the data, pass a factor of 100.--everyall factor— Decimates the input. This works exactly like--every, except it applies to all the curves.--using curveID expression
Specifies a "using" expression to micromanage the plot, bestie. This one is powerful — it lets gnuplot read your input data in whatever unhinged arbitrary way you want. A "using" expression is literally just you telling gnuplot how to map the input columns of data onto the tuples that the plotting style is expecting. Go read the "'using' expressions" section above for the full tea. 💅
--usingall expression— the global version of"using". Works exactly the same as--using, except it applies to all the curves at once. Slay. ✨--cmds xxx— extra commands you wanna pass straight on to gnuplot, verbatim. Like, no filter, no edits. These could carry extra global styles for instance. You can pass this one multiple times. 🎀--extracmds xxx— yeah it's just a synonym for--cmds xxx. Same vibe, different name. 🦋--set xxx— extra 'set' commands to hand to gnuplot verbatim. So--set 'a b c'means gnuplot sees aset a b ccommand. Can be passed multiple times. 🌸--unset xxx— the opposite energy: extra 'unset' commands, passed to gnuplot verbatim.--unset 'a b c'makes gnuplot see anunset a b ccommand. Also passable multiple times. 💜--image filename— overlays your data on top of a raster image given in"filename". It gets passed through to gnuplot via--equation, andfeedgnuplotdoes not interpret it at all beyond checking that the file exists. Here's the thing though: images usually have their origin at the top-left corner, while plots put it at the bottom-left. So if the y-axis extents aren't specified (--ymin,--ymax,--set 'yrange ...'), this option will also flip the y axis around to make the image show up the right way up. And since this is just a passthrough to gnuplot, if you want finer control you can skip it and pass in--equationand--set yrange ...yourself. 👑--equation xxx— okay so gnuplot can plot both data and symbolic equations.feedgnuplotis normally a data girl, but with this option she can plot symbolic equations too. This is mostly meant to augment data plots, because if you only want equations you don't even needfeedgnuplot. Pass--equationmultiple times for multiple equations. The strings you give get passed to gnuplot directly — nothing added, nothing removed — so any styling has to live inside the string itself. Basic example:
seq 100 | awk '{print $1/10, $1/100}' |
feedgnuplot --with 'lines lw 3' --domain --ymax 1
--equation 'sin(x)/x' --equation 'cos(x)/x with lines lw 4'Here I'm plotting the incoming data (points along a line) with the given style (a line with thickness 3), and I'm plotting two damped sinusoids on the same plot. Those sinusoids are not touched by feedgnuplot styling, so their styles get set separately, exactly like in this example. Now a more complicated one:
seq 360 | perl -nE '$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)"And here the data I generate is points along the unit circle. I plot those as points, and I also plot a true circle as a parametric equation. Iconic. 💫
--equation-below xxx— synonym for--equation. These get rendered below all the other data. 🫶--equation-above xxx— like--equation, but rendered on top of all the other data. Main character energy fr. ✨--square— plot your data with aspect ratio1. For 3D plots, this controls the aspect ratio for all 3 axes. 📐--square-xy— for 3D plots, sets a square aspect ratio for ONLY the x,y axes. Not z. Just so we're clear. 💅--hardcopy xxx— if you're not streaming, output goes to the file named here. The format gets inferred from the filename, unless--terminalsays otherwise. And if--terminalis given, then--hardcopyonly sets the output filename. 🎀--terminal xxx— a string passed toset terminal. No attempts are made to validate this. None. Zero. It's on you.--hardcopysets this to some sensible defaults if--hardcopyis set to a filename ending in.png,.pdf,.ps,.epsor.svg. Want any other file type? Use both--hardcopyand--terminaltogether. 🌈--maxcurves N— the maximum allowed number of curves. Defaults to100, but you can reset it with this option. It exists purely to stop perl from gobbling up all of the system's memory when it's reading bogus data. So like, it's a seatbelt. Wear it. 😭--monotonic— if--domainis given, this checks 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 gets purged. Without--monotonic, all data is kept. Does not make sense with 3d plots. No--monotonicby default. And heads up: 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— so the options--rangesizealland--rangesizeset the number of values needed to represent each point being plotted (peep the "Multi-value style support" section above). You only need these options if unknown styles are in play, like with--styleallor--with.
--rangesize sets how many values are needed to represent the range of a point for a particular curve. This overrides any defaults that may exist for that curve only.
With --dataid, curveID is the ID. Otherwise, it's the index of the curve, starting at 0. And curveID can be a comma-separated list of IDs to which the given rangesize should apply. 🍓
--tuplesize curveID N— very similar to--rangesize, but instead of specifying just the range, this specifies the whole tuple. For instance if we're plotting circles, the tuplesize is3:x,y,radius. In a 2D plot there's a 1-dimensional domain:x, so the rangesize is2:y,radius. You can give this dimensionality either way. 💅--rangesizeall N— like--rangesize, but it applies to all the curves. Group chat, not DM. ✨--tuplesizeall N— like--tuplesize, but it applies to all the curves. Same energy. 🌸--dump— instead of printing to gnuplot, print toSTDOUT. Very useful for debugging. And plot twist: it's possible to send the output produced this way to gnuplot directly. 🔍--exit— this one controls what happens when the input data runs out, or when some part of thefeedgnuplotpipeline gets killed. It does different things depending on whether--streamis active, so read this closely, bestie. 👀
With interactive gnuplot terminals (qt, x11, wxt), the plot windows live in a separate process from the main gnuplot process. So it's possible for the main gnuplot process to exit while leaving the plot windows up — with the caveat that such decapitated windows aren't interactive. There are 3 possible states of the plotting pipeline:
- Alive:
feedgnuplot,gnuplotalive, plot window process alive, no shell prompt (shell busy withfeedgnuplot) - Half-alive:
feedgnuplot,gnuplotdead, plot window process alive (but non-interactive), shell prompt available - Dead:
feedgnuplot,gnuplotdead, 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
--exit- Half-alive. Non-interactive prompt up, and the shell accepts new commands. Without
--streamthe goal is to show a plot, so a Dead state would not be useful.
- Half-alive. Non-interactive prompt up, and the shell accepts new commands. Without
- no
--stream, all data read in or thefeedgnuplotprocess 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.
--exit- Dead. No plot is shown, and the shell accepts new commands. With
--streamthe 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. 🧹
- Dead. No plot is shown, and the shell accepts new commands. With
- no
Note that one usually invokes feedgnuplot as a part of a shell pipeline:
$ write_data | feedgnuplotIf 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— specifies the size and position of the plot window. This applies only to thex11gnuplot terminal, and has no effect otherwise. Wanna control the window size for any other terminal? Ask for that terminal explicitly, with the options specifying the size. For instance--terminal 'qt size 1024,768'. 🖼️--version— prints the version and exits. That's it. That's the whole thing. 👑
🍳 RECIPES 🍳
Ok bestie, this is the fun part. Want a whole tutorial and a gallery? The guide lives at <https://github.com/dkogan/feedgnuplot/blob/master/guide/guide.org> ✨
🌸 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 1Like, look at that. Data goes in, plot comes out. Iconic. 💅
📶 Realtime plot of network throughput 📶
This one is peeping at wlan0 on Linux, no cap.
$ 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 🔋
This cutie 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 🌡️
This one uses /proc/acpi/ibm/thermal, which reports temperatures at various locations in a Thinkpad. Very main character of it.
$ 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 -D 8.8.8.8 |
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 🖼️
You can do this with --image:
$ < features_xy.data
feedgnuplot --points --domain --image "image.png"or with --equation:
$ < features_xy.data
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, bestie. Finer control is available with --equation. 👑
So 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. the more you know ✨
💖 ACKNOWLEDGEMENT 💖
This program is originally based on the driveGnuPlots.pl script from Thanassis Tsiodras. It is available from his site at <http://users.softlab.ece.ntua.gr/~ttsiod/gnuplotStreaming.html> 🫶
🌈 REPOSITORY 🌈
<https://github.com/dkogan/feedgnuplot>
👑 AUTHOR 👑
Dima Kogan, <dima@secretsauce.net>
📜 LICENSE AND COPYRIGHT 📜
Copyright 2011-2021 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 <http://dev.perl.org/licenses/> for more information.
And that's a wrap, bestie!! 🎀 This whole page is from perl v5.40.1, dated 2026-01-28, and it's the FEEDGNUPLOT(1) manual. Go make some plots, you absolute icon 💖✨🦋
📦 where this page comes from
- ubuntu resolute: feedgnuplot 1.64-1 · Artistic-1.0-Perl OR GPL-1.0-or-later
- ubuntu stonking: feedgnuplot 1.64-1 · Artistic-1.0-Perl OR GPL-1.0-or-later
- 💖 girlified by deepseek-ai/DeepSeek-V4.1-Flash on : a language model's rewrite of the original, under its terms