**Reported in Launchpad by Adrian Chapela last update 19-09-2012 11:48:05

As you can see in the help of innobackupex (innobackupex -help):
--databases=LIST
This option specifies the list of databases that innobackupex should
back up. The option accepts a string argument. The list is of the
form "databasename1[.table_name1] databasename2[.table_name2] . .
.". If this option is not specified, all databases containing MyISAM
and InnoDB tables will be backed up. Please make sure that
--databases contains all of the InnoDB databases and tables, so that
all of the innodb.frm files are also backed up. In case the list is
very long, this can be specified in a file, and the full path of the
file can be specified instead of the list. (See option
--tables-file.)

You could specify a file containing a line with a list of databases but innobackupex doesn't understand it.

The option tables-file understand a path as a valid option, but you should write a value each line with format, database.tables and this option affects to all backup instead of databases that affects only to the part of MyISAM tables copy, so it isn't the same option.

The option should change or the help should tell us the correct way of use.

A workaround: innobackupex --databases="`cat list_of_databases`"