I'm quite new to bash scripting and usually avoid it all costs but I need to write a bash script to execute some simple things on a remote cluster. I'm having problems with a for loop that does the following:

```
for i in {1..20}
do
for j in {1..20}
do
echo (i*i + j*j ) **.5 <--- Pseudo code!
done
done
```

Can you help me with this simple math? I've thrown `$`

's everywhere and can't write it properly. If you could help me understand how variables are named/assigned in bash for loops and the limitations of bash math interpretation (how do you do the square root?) I'd be very grateful. Thanks!

Here's a decent solution:

```
for i in {1..20}
do
for j in {1..20}
do
echo "scale = 3; sqrt($i*$i + $j*$j)" | bc
done
done
```

Output will be:

```
1.414
2.236
3.162
2.236
[...etc...]
```

Arithmetic expansion needs `$((...))`

notation, so something like:

```
echo $((i*i + j*j))
```

However, bash only uses integers so you may need to use an external tool such as dc.

E.g.

```
dc -e "18k $i $i * $j $j * + v p"
```

Licensed under: CC-BY-SA with attribution

Not affiliated with: Stack Overflow