The `--enable` flag was removed in SVGO 2.0. For now, the only way to enable optional plugins is via config. Setting up a config file is out of scope for tldr so I'm just removing the deprecated flag in this PR.
See: https://github.com/svg/svgo/releases/tag/v2.0.0
I'm currently using svgo 1.3.2 which as of right now is the latest released version: https://github.com/svg/svgo/releases
The second command did not work and according to the help docs you need to specify `-o` to the output file, otherwise everything is treated as input files.