ASCII 45 — -

The hyphen-minus character serves triple duty as a hyphen in English text, a minus sign in mathematics, and a flag prefix in command-line interfaces. In programming, '-' is the subtraction and unary negation operator. In Unix commands, '-' introduces short options ('ls -la') and '--' introduces long options ('--verbose'). In CSS, '-' separates property name words ('background-color'). The single ASCII hyphen-minus replaced three typographically distinct characters — the hyphen, en dash, and minus sign — which Unicode later restored as separate code points for proper typography.

Punctuation marks serve as the structural scaffolding of written language, delineating sentences, clauses, and phrases while conveying emphasis and grouping. In programming, these same characters gain powerful additional roles as operators, statement terminators, delimiters, and syntactic markers that compilers and interpreters rely upon. This dual significance in both natural language and code syntax means punctuation characters carry outsized functional importance relative to their small count in the ASCII character set.

In the ASCII encoding table, Hyphen-Minus is assigned code point 45 in decimal (0x2D hexadecimal, 055 octal, 00101101 binary). The 7-bit ASCII standard, first published in 1963 by the American Standards Association, defines exactly 128 characters that remain the foundation of text encoding systems worldwide. UTF-8, the dominant encoding on the modern web, is fully backward compatible with ASCII — every ASCII character is encoded as the identical single byte in UTF-8, guaranteeing that Hyphen-Minus works reliably across all operating systems, programming languages, and internet protocols.