bc

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

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 sin, cos, sqrt)

-s, --standard

POSIX standard mode

-q, --quiet

Don't print welcome banner

-i, --interactive

Force interactive mode

-w, --warn

Warn about POSIX non-compliance

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:
- s(x) - Sine
- c(x) - Cosine
- a(x) - Arctangent
- l(x) - Natural log
- e(x) - Exponential
- sqrt(x) - Square root

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
"

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.

bc