locale-gen doesn't work

As I need my locale which is fa_IR.UTF-8 on my Ubuntu Server, I'm trying to install it through (sudo) locale-gen "fa_IR.UTF-8" but I don't get any output:

user@s1:~# sudo locale-gen "fa_IR.UTF-8"
user@s1:~#

AND IT DOESN'T ADD ANY LOCALE to my locales!

When I'm trying to install new locales on my Ubuntu Desktop I don't get this error and It works well! as follows:

user@s1:~# sudo locale-gen "fa_IR.UTF-8"
Generating locales...
  fa_IR.UTF-8... done
Generation complete.
user@s1:~# 

Please help me what's the problem and what shall I do?

This happened because the names of quite a few UTF-8 locales in /usr/share/i18n/SUPPORTED don't include the codeset part ".UTF-8", and fa_IR is one of those.

$ grep -E '[a-z]+_[A-Z]+ UTF-8' /usr/share/i18n/SUPPORTED | grep fa
fa_IR UTF-8

In Ubuntu 16.04 the locale-gen script has been changed, so the user doesn't need to be aware of the exact naming in SUPPORTED. Hence in 16.04 this will work:

sudo locale-gen fa_IR.UTF-8

For previous Ubuntu versions, the simplest way to create one of these locales is to use the exact name according to SUPPORTED, for example:

sudo locale-gen fa_IR

So, AbdolHosein, your question helped us improve Ubuntu. Thank you for that. :)

At last I could find the solution by doing some things manually:

1. check which locales are supported :

   less /usr/share/i18n/SUPPORTED
   

2. Add locale to list of generated

   (sudo) echo fa_IR.UTF-8 UTF-8 >> /var/lib/locales/supported.d/local
   

3. Regenerate list (it will invoke locale-gen...)

    (sudo) dpkg-reconfigure locales