These were the steps I used to install drush globally using composer in Linux (not in ~/.composer/vendor/bin logged in as root which makes absolutely no sense):

1. Login as root
2. Install composer if necessary. See. http://getcomposer.org/doc/00-intro.md#system-requirements.
3. composer global require drush/drush:6.* or composer global require drush/drush:dev-master
4. cd ~/.composer
5. composer config --global bin-dir /usr/local/bin
6. composer config --global vendor-dir /usr/local/share
7. composer install
8. cp -r vendor/ /usr/local/share/drush/drush/
9. cd /usr/local/share/drush/drush
10. composer install

Now any user with /usr/local/bin in their path can run drush. Security precaution: You might want to chown and chmod /usr/local/bin/drush so only authorized users in a certain group can execute drush.

Notes: Lines 5 and 6 create the file ~/.composer/config.json. Line 10 is needed to delete (yes, delete) the /usr/local/share/drush/drush/vendor/drush folder which is unnecessary.

These were the steps I used to install drush globally using composer in Linux (not in ~/.composer/vendor/bin logged in as root which makes absolutely no sense):

1. Login as root
2. Install composer if necessary. See. http://getcomposer.org/doc/00-intro.md#system-requirements.
3. composer global require drush/drush:6.* or composer global require drush/drush:dev-master
4. cd ~/.composer
5. composer config --global bin-dir /usr/local/bin
6. composer config --global vendor-dir /usr/local/share
7. composer install
8. cp -r vendor/ /usr/local/share/drush/drush/
9. cd /usr/local/share/drush/drush
10. composer install

Now any user with /usr/local/bin in their path can run drush.

Security precaution: You might want to chown and chmod /usr/local/bin/drush so only authorized users in a certain group can execute drush.

Notes: Lines 5 and 6 create the file ~/.composer/config.json. Line 10 is needed to delete (yes, delete) the /usr/local/share/drush/drush/vendor/drush folder which is unnecessary.

These were the steps I used to install drush globally in Linux (not in ~/.composer/vendor/bin logged in as the root user which makes absolutely no sense):

1. Login as root
2. cd ~/.composer
3. composer config --global bin-dir /usr/local/bin
4. composer config --global vendor-dir /usr/local/share
5. composer install
6. cp -r vendor/ /usr/local/share/drush/drush/
7. cd /usr/local/share/drush/drush
8. composer install

Now any user with /usr/local/bin in their path can run drush. Security precaution: You might want to chown and chmod /usr/local/bin/drush so only authorized users in a certain group can execute drush.

Notes: Lines 3 and 4 create the file ~/.composer/config.json. Line 8 is needed to delete (yes, delete) the /usr/local/share/drush/drush/vendor/drush folder which is unnecessary.

These were the steps I used to install drush globally using composer in Linux (not in ~/.composer/vendor/bin logged in as root which makes absolutely no sense):

1. Login as root
2. Install composer if necessary. See. http://getcomposer.org/doc/00-intro.md#system-requirements.
3. composer global require drush/drush:6.* or composer global require drush/drush:dev-master
4. cd ~/.composer
5. composer config --global bin-dir /usr/local/bin
6. composer config --global vendor-dir /usr/local/share
7. composer install
8. cp -r vendor/ /usr/local/share/drush/drush/
9. cd /usr/local/share/drush/drush
10. composer install

Now any user with /usr/local/bin in their path can run drush. Security precaution: You might want to chown and chmod /usr/local/bin/drush so only authorized users in a certain group can execute drush.

Notes: Lines 5 and 6 create the file ~/.composer/config.json. Line 10 is needed to delete (yes, delete) the /usr/local/share/drush/drush/vendor/drush folder which is unnecessary.