Convert a graph using stdin and stdout

Convert a graph from `gml` to `gv` format.
Converters: `gml2gv`, `gv2gml`, `gv2gxl`, `gxl2gv`, `graphml2gv` & `mm2gv`.
More information: <https://graphviz.org/pdf/gml2gv.1.pdf>.
Trick copyright: tl;dr; <https://github.com/tldr-pages/tldr>

cat {{input.gml}} | gml2gv > {{output.gv}}

click the source code to copy install gml2gv on any operating system with command-not-found.com