Human friendly input/output for text interfaces using Python
Python Makefile Shell


humanfriendly: Human friendly input/output in Python

The functions and classes in the humanfriendly package can be used to make text interfaces more user friendly. Some example features:

  • Parsing and formatting numbers, file sizes, pathnames and timespans in simple, human friendly formats.
  • Easy to use timers for long running operations, with human friendly formatting of the resulting timespans.
  • Prompting the user to select a choice from a list of options by typing the option's number or a unique substring of the option.
  • Terminal interaction including text styling (ANSI escape sequences), user friendly rendering of usage messages and querying the terminal for its size.

The humanfriendly package is currently tested on Python 2.6, 2.7, 3.4, 3.5 and PyPy.

Getting started

It's very simple to start using the humanfriendly package:

>>> import humanfriendly
>>> user_input = raw_input("Enter a readable file size: ")
Enter a readable file size: 16G
>>> num_bytes = humanfriendly.parse_size(user_input)
>>> print num_bytes
>>> print "You entered:", humanfriendly.format_size(num_bytes)
You entered: 16 GB
>>> print "You entered:", humanfriendly.format_size(num_bytes, binary=True)
You entered: 14.9 GiB

Command line

Usage: humanfriendly [OPTIONS]

Human friendly input/output (text formatting) on the command line based on the Python package with the same name.

Supported options:

Option Description
-c, --run-command Execute an external command (given as the positional arguments) and render a spinner and timer while the command is running. The exit status of the command is propagated.
--format-table Read tabular data from standard input (each line is a row and each whitespace separated field is a column), format the data as a table and print the resulting table to standard output. See also the --delimiter option.
-d, --delimiter=VALUE Change the delimiter used by --format-table to VALUE (a string). By default all whitespace is treated as a delimiter.
-l, --format-length=LENGTH Convert a length count (given as the integer or float LENGTH) into a human readable string and print that string to standard output.
-n, --format-number=VALUE Format a number (given as the integer or floating point number VALUE) with thousands separators and two decimal places (if needed) and print the formatted number to standard output.
-s, --format-size=BYTES Convert a byte count (given as the integer BYTES) into a human readable string and print that string to standard output.
-t, --format-timespan=SECONDS Convert a number of seconds (given as the floating point number SECONDS) into a human readable timespan and print that string to standard output.
--parse-size=VALUE Parse a human readable data size (given as the string VALUE) and print the number of bytes to standard output.
--parse-length=VALUE Parse a human readable length (given as the string VALUE) and print the number of metres to standard output.
-h, --help Show this message and exit.

A note about size units

When I originally published the humanfriendly package I went with binary multiples of bytes (powers of two). It was pointed out several times that this was a poor choice (see issue #4 and pull requests #8 and #9) and thus the new default became decimal multiples of bytes (powers of ten):

Unit Binary value Decimal value
KB 1024 1000
MB 1048576 1000000
GB 1073741824 1000000000
TB 1099511627776 1000000000000

The option to use binary multiples of bytes remains by passing the keyword argument binary=True to the format_size() and parse_size() functions.


The latest version of humanfriendly is available on PyPI and GitHub. The documentation is hosted on Read the Docs. For bug reports please create an issue on GitHub. If you have questions, suggestions, etc. feel free to send me an e-mail at


This software is licensed under the MIT license.

© 2017 Peter Odding.