-PUPPETLABS_GPG_KEY_SHORT_ID = 'EF8D349F'
-PUPPETLABS_GPG_KEY_LONG_ID = '7F438280EF8D349F'
-PUPPETLABS_GPG_KEY_FINGERPRINT = '6F6B15509CF8E59E6E469F327F438280EF8D349F'
-PUPPETLABS_APT_URL = 'apt.puppetlabs.com'
-PUPPETLABS_GPG_KEY_FILE = 'DEB-GPG-KEY-puppet'
-CENTOS_GPG_KEY_SHORT_ID = 'C105B9DE'
-CENTOS_GPG_KEY_LONG_ID = '0946FCA2C105B9DE'
-CENTOS_GPG_KEY_FINGERPRINT = 'C1DAC52D1664E8A4386DBA430946FCA2C105B9DE'
-CENTOS_REPO_URL = 'ftp.cvut.cz/centos'
-CENTOS_GPG_KEY_FILE = 'RPM-GPG-KEY-CentOS-6'
-
-SHOULD_NEVER_EXIST_ID = 'EF8D349F'
-
-KEY_CHECK_COMMAND = "apt-key adv --list-keys --with-colons --fingerprint | grep "
-PUPPETLABS_KEY_CHECK_COMMAND = "#{KEY_CHECK_COMMAND} #{PUPPETLABS_GPG_KEY_FINGERPRINT}"
-CENTOS_KEY_CHECK_COMMAND = "#{KEY_CHECK_COMMAND} #{CENTOS_GPG_KEY_FINGERPRINT}"
+PUPPETLABS_GPG_KEY_SHORT_ID = 'EF8D349F'.freeze
+PUPPETLABS_GPG_KEY_LONG_ID = '7F438280EF8D349F'.freeze
+PUPPETLABS_GPG_KEY_FINGERPRINT = '6F6B15509CF8E59E6E469F327F438280EF8D349F'.freeze
+PUPPETLABS_APT_URL = 'apt.puppetlabs.com'.freeze
+PUPPETLABS_GPG_KEY_FILE = 'DEB-GPG-KEY-puppet'.freeze
+CENTOS_GPG_KEY_SHORT_ID = 'C105B9DE'.freeze
+CENTOS_GPG_KEY_LONG_ID = '0946FCA2C105B9DE'.freeze
+CENTOS_GPG_KEY_FINGERPRINT = 'C1DAC52D1664E8A4386DBA430946FCA2C105B9DE'.freeze
+CENTOS_REPO_URL = 'ftp.cvut.cz/centos'.freeze
+CENTOS_GPG_KEY_FILE = 'RPM-GPG-KEY-CentOS-6'.freeze
+
+SHOULD_NEVER_EXIST_ID = 'EF8D349F'.freeze
+
+KEY_CHECK_COMMAND = 'apt-key adv --list-keys --with-colons --fingerprint | grep '.freeze
+PUPPETLABS_KEY_CHECK_COMMAND = "#{KEY_CHECK_COMMAND} #{PUPPETLABS_GPG_KEY_FINGERPRINT}".freeze
+CENTOS_KEY_CHECK_COMMAND = "#{KEY_CHECK_COMMAND} #{CENTOS_GPG_KEY_FINGERPRINT}".freeze