Octal
Octal is a base-8 numeral system that uses eight symbols: 0 through 7. Like other positional numeral systems, the value of a digit is its face value multiplied by eight raised to the power of its position. In octal, each digit represents three binary digits, since 2^3 equals 8, which makes octal convenient for representing binary data. Converting between octal and binary is straightforward by grouping bits in sets of three.
Historically, octal was widely used in early computing and computer engineering, particularly where binary data could
Notation varies by language: many languages denote octal literals with a leading zero (for example 0755 in
See also: base-8 numeral system; Unix file permissions; binary and hexadecimal representations.