How do you find the factorial of a number in a Bash script?

Question

In shell scripting how to find factorial of a number?

Answer 1

10! in bash:

f=1; for k in {1..10}; do f=$[$k * $f] ; done; echo $f

or here in a step by step fashion:

$ t=$(echo {1..10})
$ echo $t
1 2 3 4 5 6 7 8 9 10
$ t=${t// /*}
$ echo $t
1*2*3*4*5*6*7*8*9*10
$ echo $[$t]
3628800