As you may know, the famous <a href="https://helloacm.com/teaching-kids-programming-sum-of-distinct-positive-factorial-numbers-via-depth-first-search-algorithm/" title="Teaching Kids Programming – Sum of Distinct Positive Factorial Numbers via Depth First Search Algorithm">factorial</a> can be done in Recursion via:

```
f(n) = n * f(n-1) where  f(0) = f(1) = 1
```

<a href="https://helloacm.com/bash-function-to-install-docker/" title="BASH Function to Install Docker">BASH</a> supports function declaration and recursion - just like other modern programming language. See below the Recursive function to compute the factorial values.

```
#!/bin/bash

function f() {
    local n=$1
    if [[ $n -eq 0 ]]; then
        echo 1
    else
        echo $((n*$(f $n-1)))
    fi
}

for i in {1..10}; do
    echo "$i!=$(f $i)"
done
```

This BASH script prints the first 10 factorial numbers:

```
1!=1
2!=2
3!=6
4!=24
5!=120
6!=720
7!=5040
8!=40320
9!=362880
10!=3628800
```

We use "local" to keep the variables at scope of function, and we can use $() to call a function recursively.

See also: <a href="https://helloacm.com/teaching-kids-programming-recursion-in-five-minutes/" title="Teaching Kids Programming – Recursion in Five Minutes">Teaching Kids Programming – Recursion in Five Minutes</a>

Reposted to [Blog](https://helloacm.com/recursive-factorial-function-in-bash-programming/)



^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Thank you for reading ^^^^^^^^^^^^^^^
---------------
## NEW! [Following my Trail (Upvote or/and Downvote)](https://steemit.com/witness-category/@justyy/following-my-trail-upvote-or-and-downvote-by-authorizing-posting-key-to-me)


Follow me for topics of *Algorithms, Blockchain and Cloud.*
I am @justyy - a Steem Witness
[https://steemyy.com](https://steemyy.com)

#### My contributions
- [Video Downloader](https://weibomiaopai.com/download-video-parser.php)
- [Steem Blockchain Tools](https://steemyy.com)
- [Free Cryptos API](https://steemit.com/witness-category/@justyy/serverless-api-to-query-the-cryptos-and-fiat)
- [VPS Database](https://anothervps.com/vps-database/)
- [Computing Technology Blog](https://helloacm.com)
- [A few useless tools](https://helloacm.com/tools/)
- [And some other online software/tools](https://steakovercooked.com/Software.Home)
- [Merge Files/Videos](https://slowapi.com/merge-videos/)
- [LOGO Turtle Programming Chrome Extension](https://chrome.google.com/webstore/detail/logo-turtle-graphics/dcoeaobaokbccdcnadncifmconllpihp)
- [Teaching Kids Programming - Youtube Channel](https://www.youtube.com/channel/UCK2ugmUOoYne1qQfSAph4nQ?view_as=subscriber) and [All Contents](https://github.com/DoctorLai/Teaching-Kids-Programming/blob/main/README.md)

#### Delegation Service
[Important Update of Delegation Service!](https://steemit.com/witness-category/@justyy/important-update-of-delegation-service)

- Delegate 1000 to justyy: [Link](https://steemyy.com/sp-delegate-form/?delegatee=justyy&amp;amount=1000)
- Delegate 5000 to justyy: [Link](https://steemyy.com/sp-delegate-form/?delegatee=justyy&amp;amount=5000)
- Delegate 10000 to justyy: [Link](https://steemyy.com/sp-delegate-form/?delegatee=justyy&amp;amount=10000)

#### Support me
If you like my work, please: 
- [Buy Me a Coffee](https://justyy.com/out/buymeacoffee), Thanks!
- [Become my Sponsor](https://github.com/sponsors/DoctorLai), Thanks!
- Voting for me:
https://steemit.com/~witnesses type in **justyy** and click ***VOTE***
https://steemyy.com/images/vote-for-justyy.jpg


1. Delegate SP: https://steemyy.com/sp-delegate-form/?delegatee=justyy
2. Vote @justyy as Witness:  https://steemyy.com/witness-voting/?witness=justyy&amp;action=approve
3. Set @justyy as Proxy: https://steemyy.com/witness-voting/?witness=justyy&amp;action=proxy
Alternatively, you can vote witness or set proxy here: https://steemit.com/~witnesses


-------------