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

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title	description	keywords	categories	menu	toc	signature	relatedfuncs
upper	Converts all characters in a string to uppercase		functions	docs parent functions		upper INPUT strings.ToUpper INPUT

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

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