bc

Arbitrary precision calculator

low risk

interactive breakdown — edit the command and press Explain
$ 
What it does

Calculator language; use -l for floating point.

Common flags
FlagMeaning
-lLoad math library, scale=20
Examples
echo "scale=2; 10/3" | bc3.33 · explain & risk-check →
Related
expr
Open the full explainer →More in Shell & Scripting

Reference text is hand-written and may be incomplete — check man bc for your version. Test destructive commands on a non-production system first.