"Query and update data structures from the command line. Comparable to jq/yq but supports JSON, TOML, YAML and XML" (ib., 2020-11-05)
"converts all posts, pages, taxonomies, metadata, and settings to Markdown and YAML which can be dropped into Jekyll"
"tool to convert PDF articles (newspaper, academic) to MOBI or EPUB documents"
Txt2tags is a document generator. It reads a text file with minimal markup such as **bold** and //italic// and converts it to [various markup languages and formats].
Previously at https://code.google.com/p/csvfix/
Bash script that performs a number of encodings on the first argument string
Convert files from one markup format into another. Pandoc can convert documents in markdown, reStructuredText, textile, HTML, or LaTeX
See also c't 2011/19 p118-.