Install Drush with Composer

noah@ubuntuServer:~ $ php composer.phar
Could not open input file: composer.phar
noah@ubuntuServer:~ $ php -r "copy('https://getcomposer.org/installer', 'composer-setup.php');"
noah@ubuntuServer:~ $ php -r "if (hash_file('SHA384', 'composer-setup.php') === '070854512ef404f16bac87071a6db9fd9721da1684cd4589b1196c3faf71b9a2682e2311b36a5079825e155ac7ce150d') { echo 'Installer verified'; } else { echo 'Installer corrupt'; unlink('composer-setup.php'); } echo PHP_EOL;"
Installer verified
noah@ubuntuServer:~ $ php composer-setup.php
All settings correct for using Composer
PHP Warning:  file_put_contents(/home/noah/.composer/keys.dev.pub): failed to open stream: Permission denied in /home/noah/composer-setup.php on line 466
PHP Warning:  file_put_contents(/home/noah/.composer/keys.tags.pub): failed to open stream: Permission denied in /home/noah/composer-setup.php on line 483
Downloading 1.1.2...

Composer successfully installed to: /home/noah/composer.phar
{
    "require": {
        "monolog/monolog": "1.0.*"
    }
}
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"composer.json" [New] 5L, 62C written
noah@ubuntuServer:~/tmp $ php composer.phar install
Could not open input file: composer.phar
noah@ubuntuServer:~/tmp $ composer install
Cannot create cache directory /home/noah/.composer/cache/repo/https---packagist.org/, or directory is not writable. Proceeding without cache
Cannot create cache directory /home/noah/.composer/cache/files/, or directory is not writable. Proceeding without cache
Cannot create cache directory /home/noah/.composer/cache/repo/https---packagist.org/, or directory is not writable. Proceeding without cache
Loading composer repositories with package information
Updating dependencies (including require-dev)
  - Installing monolog/monolog (1.0.2)
    Downloading: 100%

Writing lock file
Generating autoload files
noah@ubuntuServer:~/tmp $ sudo chown -R $USER $HOME/.composer
[sudo] password for noah:
noah@ubuntuServer:~/tmp $ composer install
Loading composer repositories with package information
Installing dependencies (including require-dev) from lock file
Nothing to install or update
Generating autoload files
noah@ubuntuServer:~/tmp $ composer --version
Composer version 1.1.2 2016-05-31 19:48:11
noah@ubuntuServer:~/tmp $ export PATH="$HOME/.composer/vendor/bin:$PATH"
noah@ubuntuServer:~/tmp $ bash
noah@ubuntuServer:~/tmp $ echo $PATH
/home/noah/.composer/vendor/bin:/home/noah/.composer/vendor/bin:/home/noah/.composer/vendor/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/snap/bin
noah@ubuntuServer:~/tmp $ composer global require drush/drush:dev-master
Changed current directory to /home/noah/.composer
./composer.json has been updated
Loading composer repositories with package information
Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - Installation request for drush/drush dev-master -> satisfiable by drush/drush[dev-master].
    - drush/drush dev-master requires codegyre/robo ~1.0.0-beta1 -> satisfiable by codegyre/robo[1.0.0-beta1] but these conflict with your requirements or minimum-stability.


Installation failed, reverting ./composer.json to its original content.
noah@ubuntuServer:~/tmp $ composer global require drush/drush:dev-master