## 3.5 Filename extensions

You can use any filename extension for the input file, but if you do not use the recommended extension for a particular format you may need to manually specify the output format; for details, see Invoking `lilypond-book`. Otherwise, `lilypond-book` automatically selects the output format based on the input filename’s extension.

> extension | output format
> ‘`.html`’ | HTML
> ‘`.htmly`’ | HTML
> ‘`.itely`’ | Texinfo
> ‘`.latex`’ | LaTeX
> ‘`.lytex`’ | LaTeX
> ‘`.lyxml`’ | DocBook
> ‘`.tely`’ | Texinfo
> ‘`.tex`’ | LaTeX
> ‘`.texi`’ | Texinfo
> ‘`.texinfo`’ | Texinfo
> ‘`.xml`’ | HTML

If you use the same filename extension for the input file than the extension `lilypond-book` uses for the output file, and if the input file is in the same directory as `lilypond-book` working directory, you must use ‘`--output`’ option to make `lilypond-book` running, otherwise it will exit with an error message like “Output would overwrite input file”.

其他语言：deutsch, español, français, italiano, 日本語。
About automatic language selection.

#### LilyPond — Usage v2.18.2 (稳定分支).