HTML Tidy is an old and classic program that can be used to fix errors and correct indentation of a HTML file.
It can be installed easily in Ubuntu:
$ sudo apt install tidy
However, the version from Ubuntu is extremely old and does not support HTML5. It is pretty pointless to install and use this ancient version today.
To download and build the latest HTML Tidy, try these commands:
$ git clone https://github.com/htacg/tidy-html5.git $ cd tidy-html5 $ cd build/cmake $ cmake ../.. $ cmake --build . --config Release
To install it:
$ sudo make install
Tried with: HTML Tidy 5.2.0 and Ubuntu 14.04