sh Arithmetic Expansion Parameter Expansion
Example
Loop n times:
while [ $((i=${i:=0}+1)) -le "$n" ]; do
echo line $i
done
Output for n=5:
line 1
line 2
line 3
line 4
line 5
Manipulating decimals:
$ i=3.14159; echo $((${i%.*}*2))
6
$ i=3.14159; echo $((${i#*.}*2))
28318
