I've seen binary and hex used quite often but never octal. Yet octal has it's own convention for being used in some languages (ie, a leading 0 indicating octal base). When is octal used? What are some typical situations when one would use octal or octal would be easier to reason about? Or is it merely a matter of taste?
Octal is used as a shorthand for representing file permissions on UNIX systems. For example, file mode rwxr-xr-x would be 0755.