A
vertical tab, what the hell is it? Well it is an
ASCII character. Number 11 to be exact. In
Octal it is 013. In
Hexidecimal it is 0B. Also known as VT. In C and C-like languages '
\v' is used as it's
escape character.
Great! But what the hell is a vertical tab?
Well, like the name says it is a tab, but it goes vertically. In our left to right world it seems pretty useless. One source I found, while speaking of ASCII characters in general, says "Note that many of these have little practical significance in modern usage. The mnemonics derive from teleprinter conventions that predate digital computers."1
I'm still not sure how it might be used. Maybe if working with paper or doing complex CLI applications it might be useful.
From the Perl RFC 327, \v for Vertical Tab, Russ Allbery notes:
The last time I used a vertical tab intentionally and for some productive purpose was about 1984.
1http://www.python.org/doc/current/lib/module-curses.ascii.html