qalc

Launch in interactive mode

$ qalc [[-i|--interactive]]

$ qalc [[-t|--terse]]

$ qalc [[-e|--exrates]]

$ qalc [66+99|2^4|6 feet to cm|1 bitcoin to USD|20 kmph to mph|...]

$ qalc --[list-functions|list-prefixes|list-units|list-variables]

$ qalc [[-f|--file]] [path/to/file]

qalc [options] [expression]

--evaluate, -e
    Evaluate the given expression and exit. (This is the default if an expression is provided.)

--interactive, -i
    Run qalc in interactive mode, allowing continuous input of expressions.

--convert, -c
    Convert the result of the expression to specified units or currencies (e.g., 10m -> ft).

--terse, -t
    Produce terse output, omitting the expression prefix and other decorative elements.

--precision, -p
    Set the numeric precision for calculations.

--set, -s
    Set internal variables or options (e.g., base=hex or auto_post_conversion=off).

--list-functions, -a
    List all available mathematical functions supported by qalc.

--list-units, -u
    List all supported units and currencies.

--base, -B
    Set the default output number base (e.g., binary, octal, hexadecimal).

--help, -h
    Display a help message and exit.

--version, -v
    Show version information and exit.

qalc is the command-line interface for Qalculate!, a powerful and versatile desktop calculator. It provides advanced mathematical functionality directly in your terminal, supporting everything from basic arithmetic to complex symbolic calculations, unit conversions, currency exchange, and statistical analysis. Users can evaluate expressions non-interactively or enter an interactive mode for continuous calculations. Its extensive built-in function library, support for variables, and ability to handle arbitrary precision numbers make it an indispensable tool for engineers, scientists, and anyone needing robust calculation capabilities beyond simple bc or expr.

qalc relies on the Qalculate! library, which must be installed on the system. While extremely powerful, its comprehensive features can sometimes present a steeper learning curve compared to simpler calculators. Unit and currency exchange rates require occasional updates from online sources to remain accurate.

When run with no arguments or the -i option, qalc enters an interactive shell where users can type expressions continuously, define variables, create custom functions, and manage the calculation environment. This mode is ideal for complex, multi-step computations.

One of qalc's most powerful features is its robust unit and currency conversion capabilities. Expressions like 10 USD to EUR or 50 miles / hour to km/s are easily handled. It can automatically fetch up-to-date currency exchange rates and supports a vast library of physical units, making it invaluable for scientific and engineering calculations.

Beyond numerical computation, qalc can perform symbolic operations such as simplifying algebraic expressions, differentiating functions (e.g., diff(x^2 + 2x, x)), and solving equations. This makes it a versatile tool for tasks that traditionally require more specialized mathematical software.

qalc is part of the Qalculate! project, an open-source, multi-platform desktop calculator developed by Niklas Knutsson. The project began around 2001, aiming to provide a powerful and versatile calculator with a user-friendly interface. The command-line qalc utility was developed alongside the GUI, offering the core calculation engine's capabilities to script and terminal environments, maintaining feature parity with the underlying library and ensuring consistent functionality.

bc(1), dc(1), expr(1), qalculate(1)