I added \definecolor{bg}{HTML}{282828} to my .tex file and now latex --shell-escape file.tex is breaking with less-than-helpful error messages.
File.tex looks like:
\documentclass[varwidth=40cm,border=2mm]{standalone}
\usepackage{minted}
\usemintedstyle{solarized}
\definecolor{bg}{HTML}{282828}
\begin{document}
\begin{LARGE}
\inputminted{filetype}{example}
\end{LARGE}
\end{document}
(note my shell script changes {filetype} and {example} to appropriate values)
The error message says
! Undefined control sequence.
l.5 \definecolor
{bg}{HTML}{282828}
?
! LaTeX Error: Missing \begin{document}.
But as you can see \begin{document} is not actually missing.
I see lots of other questions about "undefined control sequence" but don't understand what it's actually about nor what it means in this context.