What is the HTML unicode character for a "tall" right chevron? [closed]

Use '›'

› -> single right angle quote. For single left angle quote, use ‹

From the description and from the reference to the search box in the Ubuntu site, I gather that you actually want an arrowhead character pointing to the right. There are no Unicode characters designed to be used as arrowheads, but some of them may visually resemble an arrowhead.

In particular, if you draw your idea of the character at Shapecatcher.com, you will find many suggestions, such as “〉” RIGHT-POINTING ANGLE BRACKET' (U+232A) and “❭” MEDIUM RIGHT-POINTING ANGLE BRACKET ORNAMENT (U+276D).

Such characters generally have limited support in fonts, so you would need to carefully write a longish font-family list or to use a downloadable font. See my Guide to using special characters in HTML.

Especially if the intended use is as a symbol in a search box, as the reference to the Ubuntu page suggests, it is questionable whether you should use a character at all. It’s not really an element of text here; rather, a graphic symbol that accompanies text but isn’t a part of it. So why take all the trouble with using a character (safely), when it isn’t really a character?