---
name: "byteprefix"
section: "5"
platform: "linux"
package: "libkibi0"
version: "0.1.1-2.1+b2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/byteprefix"
---

# byteprefix(5)

Configuration for display of sizes

## 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)](/units/7.md)