graphtail

You've got a program that outputs a bunch of numbers to a CSV file? You want to visualize those numbers with graphs in real-time, while the program is still running and appending new numbers? If you can say yes to both those questions, graphtail might be the tool you need.

Installing

From source

First of all you'll need git and cmake to acquire and build the project. Then you can run:

git clone https://github.com/demogorgon1/graphtail.git
cd graphtail
mkdir build
cd build
cmake ..
cmake --build .

On Windows, if successful, you'll find graphtail.exe in src\Debug. On Linux (and similar), if successful, you can run make install to install graphtail.

Downloading binaries

For Windows you can download the zip'd .exe file available under "Releases".

Usage

graphtail [options] <input files>

Renders numeric data from input CSV files into a window. Any changes to the files will automatically update the window.

Option	Description
--row_delim=<character>	Character used as row deliminator in CSV files or new_line. Defaults to new_line.
--column_delim=<character>	Character used as column deliminator in CSV files. Defaults to ;.
--width=<width> --height=<height>	Sets the size of the window. Defaults to a 1000x500.
--font_size=<size>	Sets the size of the font used to display information. Defaults to 14.
--x_step=<pixels>	Instead of stretching graph to fit the width of the window, each data point will advance the specified number of pixels the x-axis. This option can be used in a group definition.
--y_min=<min> --y_max=<min>	Clamp the graph y-axis to the specified range. Default is to stretch. This option can be used in a group definition.
--histogram_threshold=<value>	Histogram values must be higher than this to be rendered. Default is to not have a threshold. This option can be used in a group definition.
--is_size	Numbers will be shown with K/M/G suffixes if large enough. This option can be used in a group definition.
--groups=<definition>	Defines graph groups. See example below. If no groups are defined, all columns will get their own group automatically.
--config=<path>	Loads configuration from specified file. See below for an example of a configuration file.

Keyboard shortcuts

Key	Action
ESC	Terminate program.
F1	Toggle x-axis stretching to fit window width.

Group definitions

All graphs will be shown separately per default, but you can group specific ones together if you want to with the --groups option.

Group description syntax looks a bit wonky because it's easy to parse, but it's quite simple:

{ marks the beginning of a group and } ends it. Inside the brackets you can use i(column) to added column to the group. column can also be a wildcard (for example *something*), which will cause any column with a name matching the wildcard to be added to the group. Inside the group you can also specify group-specific parameters with !option=value. You can see which options can be specified per group in the list above. Use h(name)(column1, column2, ...) to turn the group into a histogram heatmap.

Example 1

--groups={i(foo)i(bar)!y_min=0!y_max=1}{i(baz)}

This will cause the columns foo and bar to be added to the same group and the y-axis will be clamped between 0 and 1. The column baz will be put in a separate group.

Example 2

--groups={h(foo)(foo1,foo2,foo3,foo4)!histogram_threshold=0}

Render columns foo1, foo2, foo3, and foo4 as a histogram heatmap named foo. Cells of the heatmap must have a value of at least 0 to be rendered.

Configuration files

A configuration file is a list of statements:

input /path/to/some/csv-file
width 500
height 500
groups {i(foo)i(bar)}

Alternatively you can specify values like this:

begin groups
  {
    i(foo)
    i(bar)
  }
end

This is particularily useful if you have a lot of groups and you want your configuration to be more readable.