Write your PHP code. 

<?php
bindtextdomain('messages', './');

switch ($argv[1]) {
    case 'de':
        putenv("LC_ALL=de");
        break;
    case 'en':
    default:
        putenv("LC_ALL=en");
        break;
}


print _("Hey");
print "\n<br>\n";
print _("This is example number ") . "2!";
?>
Extract the strings from the file, using the xgettext(1) program. 

]$ xgettext -a gettext_ex.php
Create the appropriate subdirectories, and place your portable object files there. 

]$ mkdir -p en/LC_MESSAGES/
]$ mv messages.po en/LC_MESSAGES/
]$ mkdir -p de/LC_MESSAGES/
]$ cp en/LC_MESSAGES/messages.po de/LC_MESSAGES/messages.po
Translate it!

Now compile all of your translations with msgfmt(1) 

]$ msgfmt messages.po -o messages.mo