Drupal - drush - переменная DRUSH PHP

Через переменную DRUSH_PHP - можно переопределить путь к другой версии PHP:

$ export DRUSH_PHP=/usr/bin/php55
$ echo $DRUSH_PHP
/usr/bin/php55

$ ./drush
Execute a drush command. Run `drush help [command]` to view command-specific help.  Run `drush topic` to read even more documentation.
Global options (see `drush topic core-global-options` for the full list):
-d, --debug                               Display even more information, including internal messages.
-h, --help                                This help system.
-ia, --interactive                        Force interactive mode for commands run on multiple targets (e.g. `drush @site1,@site2 cc --ia`).
-n, --no                                  Assume 'no' as answer to all prompts.