bc

Arbitrary precision calculator language

TLDR

Calculate expression

$ echo ["2+2"] | bc

Division with decimals

$ echo ["scale=2; 10/3"] | bc

Run bc script

$ bc [script.bc]

Math library

$ bc -l

Evaluate an expression directly

$ bc -e "[scale=2; 100/3]"

Interactive calculator

$ bc

bc is an arbitrary precision calculator language. It supports interactive calculation, scripting, and mathematical operations with user-definable precision for decimal calculations.The tool has been a Unix standard for decades and is widely used in shell scripts for arithmetic.

PARAMETERS

-l, --mathlib

Load math library (includes functions like s, c, a, l, e, and sets scale to 20)

-s, --standard

POSIX standard mode; error on any non-POSIX extensions

-q, --quiet

Don't print the normal GNU bc welcome banner

-i, --interactive

Force interactive mode

-w, --warn

Warn about POSIX non-compliance

-e expression, --expression expression

Evaluate expression; multiple -e options are processed in order

-v, --version

Print version number and exit

SPECIAL VARIABLES

scale

Number of decimal places (default: 0)

ibase

Input base (default: 10)

obase

Output base (default: 10)

OPERATORS

- **+, -, *, /** - Basic arithmetic- % - Modulo- ^ - Exponentiation- ++, -- - Increment/decrement- ==, !=, <, > - Comparisons

FUNCTIONS

With -l flag (also sets scale to 20):- s(x) - Sine (x in radians)- c(x) - Cosine (x in radians)- a(x) - Arctangent (returns radians)- l(x) - Natural logarithm- e(x) - Exponential (e raised to x)- sqrt(x) - Square root (available without -l)

WORKFLOW

$ # Simple math
echo "2+2" | bc

# Floating point
echo "scale=4; 22/7" | bc

# Hex to decimal
echo "ibase=16; FF" | bc

# Square root
echo "sqrt(2)" | bc -l

# Multiple operations
bc <<< "
scale=2
x = 5
y = 3
x / y
"

INSTALL

sudo apt install bc

sudo dnf install bc

sudo pacman -S bc

sudo apk add bc

sudo zypper install bc

brew install bc

nix profile install nixpkgs#bc

CAVEATS

Unusual syntax for programmers. Default integer division (set scale). Variables persist in interactive mode. Limited string handling. For modern scripts, consider awk or programming languages.

HISTORY

bc was developed at Bell Labs for Unix in 1975 by Robert Morris and Lorinda Cherry, based on the earlier dc calculator. The GNU version, which is the most widely used today, was written by Philip A. Nelson.

bc