BYTEPREFIX(5)

NAME
byteprefix - Configuration for display of sizes

DESCRIPTION
There are two standard ways to use units in computing: base 10 (1 k = 10^3 = 1 000) and base 2 (1 K = 2^10 = 1 024). Historically, most computer programs have used units in base 2, where 1 KB = 1 024 bytes, 1 MB = 1 048 576 bytes, etc. However, users are more likely to expect and understand sizes in base 10, as this is the norm outside of computing.

This configuration file is a method for configuring programs (that use libkibi) to display sizes in the user's preferred style. It can be configured through a configuration file or environment variable (which takes precedence).

When not using the "historic" style, IEC-style prefixes (KiB, MiB, etc.) are used for base 2 units, to disambiguate them from base 10 units (kB, MB, etc.).

OPTIONS
There are three possible styles (Default: base10):

base2
    Display all sizes in Base 2 with IEC prefixes.

    1 KiB = 1 024 bytes.
    1 MiB = 1 024 KiB = 1 048 576 bytes.
    1 GiB = 1 024 MiB = 1 048 576 KiB = 1 073 741 824 bytes.

base10
    Display all sizes in Base 10, except for sizes of RAM, which use base 2 with IEC prefixes.

    Everything except RAM:
    1 kB = 1 000 bytes.
    1 MB = 1 000 kB = 1 000 000 bytes.
    1 GB = 1 000 MB = 1 000 000 kB = 1 000 000 000 bytes.

    RAM:
    1 KiB = 1 024 bytes.
    1 MiB = 1 024 KiB = 1 048 576 bytes.
    1 GiB = 1 024 MiB = 1 048 576 KiB = 1 073 741 824 bytes.

historic
    Display all sizes in Base 2, without IEC prefixes.

    1 KB = 1 024 bytes.
    1 MB = 1 024 KB = 1 048 576 bytes.
    1 GB = 1 024 MB = 1 048 576 KB = 1 073 741 824 bytes.

    Not recommended. This style uses base units 2 with prefixes usually associated with base 10 units. While it uses KB rather than the SI (base 10) kB, there is no such distinction beyond the kilobyte range, and the units are ambiguous.

ENVIRONMENT

BYTEPREFIX
    This environment variable will override the configured or default style. It should just contain one of the style names, listed in OPTIONS above.

XDG_CONFIG_HOME
    The location of the user's configuration files. If not set, it will be assumed to be ~/.config.

FILES
The preferred style can be set in a system-wide configuration file and/or in user's own configuration file (which will take precedence). If no configuration file exists, the default style is base10.

/etc/byteprefix or XDG_CONFIG_HOME/byteprefix
    This file should contain a single line: format=style. Lines beginning with # are treated as comments.

EXAMPLE
A user wanting base 2 display can set the following in ~/.config/byteprefix:

    format=base2

SEE ALSO
units(7)