hugo/docs/content/en/functions/upper.md

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title	description	date	publishdate	lastmod	keywords	categories	menu	toc	signature	workson	hugoversion	relatedfuncs	deprecated	draft	aliases
upper	Converts all characters in a string to uppercase	2017-02-01	2017-02-01	2017-02-01		functions	docs parent functions		upper INPUT strings.ToUpper INPUT				false	false

Note that upper can be applied in your templates in more than one way:

{{ upper "BatMan" }} → "BATMAN"
{{ "BatMan" | upper }} → "BATMAN"