% APEX(1) % Brett Terpstra % December 2025 # NAME apex - Unified Markdown processor supporting CommonMark, GFM, MultiMarkdown, and Kramdown # SYNOPSIS **apex** [*options*] [*file*] **apex** --combine [*files*...] **apex** --mmd-merge [*index files*...] # DESCRIPTION Apex is a unified Markdown processor that combines the best features from CommonMark, GitHub Flavored Markdown (GFM), MultiMarkdown, Kramdown, and Marked. One processor to rule them all. If no file is specified, **apex** reads from stdin. # OPTIONS ## Processing Modes **-m** *MODE*, **--mode** *MODE* : Processor mode: **commonmark**, **gfm**, **mmd** (or **multimarkdown**), **kramdown**, or **unified** (default). Each mode enables different features and syntax compatibility. ## Input/Output **-o** *FILE*, **--output** *FILE* : Write output to *FILE* instead of stdout. **-s**, **--standalone** : Generate complete HTML document with ``, ``, and `` tags. **--style** *FILE*, **--css** *FILE* : Link to CSS file(s) in document head (requires **--standalone**). Can be used multiple times or accept comma-separated list (e.g., `--css style.css --css syntax.css` or `--css style.css,syntax.css`). Overrides CSS metadata if specified. **--embed-css** : When used with **--css FILE**, read the CSS file(s) and embed their contents into `