In some cases you might want to insert some special passages for a destination format, language or operating system.
UDO supports some commands you can use to check the destination format, language, operating system and the existence of symbols.
With an !if command you start a query. If the query returns a true value the following lines will be converted until UDO reads the !endif or !else commands. If the query returns a false value UDO will ignore the following lines until !endif or !else.