Today, gitstats is used to analyze the activity information of git Repo. It finds that gnuplot is used internally, and PNG images cannot be generated. The shell that enters gnuplot finds that PNG output cannot be set. As follows:
Gnuplot> set term PNG ^ unknown or ambiguous terminal type; type just 'set Terminal' for a list
Or do not change the type to unknown.
This is because OS x is not pre-installed with X11 now (see the official message http://support.apple.com/kb/HT5293), and then I used the following method to install successfully.
1. Install X11
Http://xquartz.macosforge.org/landing/
DMG package. Download and install it.
2. Install gnuplot
Http://www.miscdebris.net/blog/2009/09/16/install-gnuplot-on-mac-os-x/
Download and drag the DMG package
Finally, use gitstats to generate a webpage (to be honest, this webpage is really ugly)
Installation and configuration of gnuplot in Mac OS X (images such as set term PNG cannot be output)