units

Start interactive mode for unit conversions

$ units

$ units "[from_unit]" "[to_unit]"

$ units "[100 kilometers]" "[miles]"

$ units "[parsec]"

$ units --terse "[from_unit]" "[to_unit]"

$ units --check

$ units -f [custom_units.dat]

$ units -V

units [options] [from-unit] [to-unit]

GNU Units converts between different systems of measurement and performs unit arithmetic. It includes a comprehensive database of over 3000 units, including historical and esoteric measurements.
In interactive mode, enter the source unit at the "You have:" prompt and the target unit at "You want:". Units checks dimensional compatibility and reports conformability errors for incompatible conversions.
The program also functions as a scientific calculator with built-in functions (sin, cos, ln, exp, etc.). Complex expressions with units are supported.

-f, --file filename

Use specified units database file.

Check that all units reduce to primitive units.

Specify numeric output format.

Print only the conversion factor (for parsing).

Give compact output without operators.

Suppress statistics and prompts.

Show more detailed output.

Force a specific locale.

Interpret - as subtraction (default).

Interpret - as multiplication.

Use old precedence for \* (higher than division).

Use new precedence for \* (default).

Print version and data file location.

Display help message.

Attempting to convert between dimensionally incompatible units (e.g., meters to seconds) produces a conformability error. The units database location varies by installation; use -V to find it. Custom unit definitions can be added to personal unit files.

The original Unix units program was included in early versions of Unix. GNU Units was written by Adrian Mariano as a free implementation with an expanded unit database. It was first released in 1996 and is maintained as part of the GNU Project. The program includes units from ancient civilizations, historical measurements, and modern scientific standards.

bc(1), dc(1), calc(1)