A possible use case scenario is making slugs for urls, containing bulgarian.

Since it is a common task, in the best Unix tradition, it is very usefull to have a simple command line filter, into which you can pipe the cyrillic text, and producing the romanized version in its output.

Here is a simple version of the command line filter cyr2lat, written in php, that does just that:

#!/usr/bin/env php
<?php
$cyr  = array('а','б','в','г','д','е','ж','з','и','й','к','л','м','н','о','п','р',
              'с','т','у','ф','х','ц','ч','ш','щ','ъ','ь','ю','я',
              'А','Б','В','Г','Д','Е','Ж','З','И','Й','К','Л','М','Н','О','П','Р',
              'С','Т','У','Ф','Х','Ц','Ч','Ш','Щ','Ъ','Ь', 'Ю','Я' );
$lat = array( 'a','b','v','g','d','e','zh','z','i','y','k','l','m','n','o','p','r',
              's','t','u','f' ,'h' ,'ts' ,'ch','sh' ,'sht' ,'a' ,'y' ,'yu','ya',
              'A','B','V','G','D','E','Zh','Z','I','Y','K','L','M','N','O','P','R',
              'S','T','U','F' ,'H' ,'Ts' ,'Ch','Sh' ,'Sht' ,'A' ,'Y' ,'Yu' ,'Ya' );

$in = fopen ("php://stdin","r");
while($line = fgets($in)){
    echo str_replace($cyr, $lat, $line);
}

Source of cyr2lat.php

To use it, just save it to a file named cyr2lat.php, then make this script executable by:

chmod 755 cyr2lat.php

... and possibly move it to a location in your path:

mv cyr2lat.php /usr/local/bin

or

mv cyr2lat.php ~/bin

After this, you can run for example:

echo "Това е текст на кирилица" | cyr2lat.php

and you will get:

Tova e tekst na kirilitsa

NB: This filter assumes that the input text is in the utf8 encoding. If you have an input text in the cp1251 encoding, just pipe it first through iconv, like this:

echo "Това е пак текст на кирилица, но този път с кодировка cp1251" |iconv -fcp1251 -tutf8 |cyr2lat.php