remedy - 1 year ago 59

Bash Question

I'm trying to write a basic script to calculate the radius and are are of a circle, PI=3.14, and the circumference is given. I am very very new to scripting, and I can't seem to figure this out.

`#!/bin/bash`

PI=3.14

CIRC=5

RAD=echo "((CIRC/2*PI))" | bc-l

printf "Radius: %.2f" $RAD

AREA=echo "((PI*RAD**2))" | bc-l

printf "Area: %.2f" $AREA

The sum of both equations are not being stored in those variables, and I have no idea why. I hope someone can help explain.

Answer Source

Below script would do it :

```
#!/bin/bash
pi=3.14
circ=5
rad=$( echo "scale=2;$circ / (2 * $pi)" | bc )
printf "Radius: %.2f\n" $rad
area=$( echo "scale=2;$pi * $rad * $rad" | bc )
printf "Area: %.2f\n" $area
```

**Notes**

- See [ command substitution ].
- Never use full uppercase variables in your script as they are usually reserved for the system, check [ this ].
`scale`

with`bc`

controls the precision, check [ this ].