change text face in string

I have a string that contains several blocks of text inside [], example:
"the gray fox [is running] from the tiger [a hungry tiger]....etc.."

I would like to display the text inside the [] as bold.

NOTE: this data comes from a DB and in order to distinguish it, I need to make it bold or a different color.

 

I would do it something simple like:

$string= "the gray fox [is running] from the tiger [a hungry tiger]....etc..";
$string= str_replace("[","<b>",str_replace("]","</b>",$string));


I don't know how efficient it would be but it works.

 

<?php
function tobold($text){ 
	return ereg_replace('\[([^\[]*)\]','<b>\1</b>',$text);
}
//Testing
echo tobold("This is [Bold]<br />");
echo tobold("This is [Bold] with nesting error]<br />");
echo tobold("This is [Bold] and [onther bold]");
?>

PHP:

This outputs:
This is Bold
This is Bold] with nesting error
This is Bold and onther bold


Note: This is basic because i'm still a noob; I hope it will help you

 

Thanks a lot, both suggestions worked like a charm!