Drush misidentifies my D7 site as drupal 8 I'm using Drush Commandline Tool 9.2.1 in a Drupal 7 webroot and I'm unable to run it.
$ drush -vvv cc all
 [preflight] Config paths: /home/user/.composer/vendor/drush/drush/drush.yml
 [preflight] Alias paths: 
 [preflight] Commandfile search paths:
             /home/user/.composer/vendor/drush/drush/src
 [bootstrap] Bootstrap to max [0.14 sec, 11.2 MB]
 [debug] Trying to bootstrap as far as we can [0.14 sec, 11.21 MB]
 [error]  `cache-clear all` is deprecated for Drupal 8 and later. 
          Please use the `cache-rebuild` command instead.

Seems to suggest that it thinks the site is D8 but it's a D7 site.
$ drush list 
(...commands listed as normal...)
! [NOTE] Drupal root not found. Pass --root or a @siteAlias in order to
see Drupal-specific commands.

Says it can't identify the root. I'm in it! And my settings file is fine at the normal location of sites/default/settings.php
Even passing --root and -l options does not help - I still get the same errors.
Never had this before. Any ideas?
EDIT
Here's why I didn't think this was a silly question:

Source: http://docs.drush.org/en/7.x/install/ at 23 Mar 2018.
I'm using Drush Commandline Tool 9.2.1 in a Drupal 7


Drush 9 only works with Drupal 8.4+ 

As seen on: http://docs.drush.org/en/master/install/ 



Uninstall Drush 9

composer global remove drush/drush


and install Drush 8

composer global require drush/drush:8.x