U0009

U+0009 is the Unicode code point commonly known as the horizontal tabulation character, or TAB. It is a control character in the ASCII and Unicode standards, assigned to decimal value 9. It is not a printable symbol and is intended to control the cursor position rather than produce a visible glyph.

Encoding and representation: In UTF-8, U+0009 is encoded as a single byte 0x09. In UTF-16 it is encoded as 00 09 in big-endian form and 09 00 in little-endian form. In UTF-32 it would be 00 00 00 09.

Usage and behavior: The tab character moves the text cursor to the next tab stop. Tab stops are implementation-defined and often default to every eight columns, though many editors allow configuration. Tabs are used to align columns in plain text and are common in tab-delimited data files (TSV). They are also used in source code to indent blocks, though many style guides prefer spaces for indentation.

Contexts in programming and data processing: In many programming languages, the tab can be inserted or represented with escape sequences such as \t or \x09, and in Unicode escapes as \u0009. In HTML, a tab is typically collapsed to a single space unless it appears inside preformatted sections or a configuration that preserves whitespace.

Compatibility and limitations: Because it is a control character, different environments render or handle it differently. In some contexts, tabs are converted to spaces or are removed by text-processing tools. In data interchange, tab characters may need escaping or may be disallowed in certain fields, depending on the format.