注意:我在此处检查的时候安装的时候遇到了一个问题，内容如下

ERROR:While executing gem ... (Gem::RemoteFetcher::FetchError)

bad response Forbidden 403 (https://gems-ruby-china.b0.upaiyun.com/quick/Marshal.4.8/cocoapods-core-1.2.0.gemspec.rz)

无效的操作，推测应该gem版本有问题，可以用一下命令查一下ruby和gem的版本号：

$ gem -v

$ ruby - v

查看之后重新更新一下gem

$ sudo gem update --system

然后会显示Latest version currently installed. Aborting.这就是最新的gem已经更新了，你可以使用了。

三 安装成功

再重新安装CocoaPods

$ sudo gem install -n /usr/local/bin cocoapods

Last login: Sat Apr1 15:07:25 on ttys001

XLsn0wdeMac-mini:~ xlsn0w$ sudo gem update --system

Password:

Updating rubygems-update

Fetching: rubygems-update-2.6.7.gem (100%)

Successfully installed rubygems-update-2.6.7

Parsing documentation for rubygems-update-2.6.7

Installing ri documentation for rubygems-update-2.6.7

Installing darkfish documentation for rubygems-update-2.6.7

Done installing documentation for rubygems-update after 30 seconds

Parsing documentation for rubygems-update-2.6.7

Done installing documentation for rubygems-update after 0 seconds

Installing RubyGems 2.6.7

RubyGems 2.6.7 installed

Parsing documentation for rubygems-2.6.7

Installing ri documentation for rubygems-2.6.7

=== 2.6.7 / 2016-09-26

Bug fixes:

* Install native extensions in the correct location when using the

`--user-install` flag. Pull request #1683 by Noah Kantrowitz.

* When calling `Gem.sources`, load sources from `configuration`

if present, else use the default sources. Pull request #1699

by Luis Sagastume.

* Fail gracefully when attempting to redirect without a Location.

Pull request #1711 by Samuel Giddins.

* Update vendored Molinillo to 0.5.1. Pull request #1714 by

Samuel Giddins.

=== 2.6.6 / 2016-06-22

Bug fixes:

* Sort installed versions to make sure we install the latest version when

running `gem update --system`. As a one-time fix, run

`gem update --system=2.6.6`. Pull request #1601 by David Radcliffe.

=== 2.6.5 / 2016-06-21

Minor enhancements:

* Support for unified Integer in Ruby 2.4. Pull request #1618

by SHIBATA Hiroshi.

* Update vendored Molinillo to 0.5.0 for performance improvements.

Pull request #1638 by Samuel Giddins.

Bug fixes:

* Raise an explicit error if Signer#sign is called with no certs. Pull

request #1605 by Daniel Berger.

* Update `update_bundled_ca_certificates` utility script for directory

nesting. Pull request #1583 by James Wen.

* Fix broken symlink support in tar writer (+ fix broken test). Pull

request #1578 by Cezary Baginski.

* Remove extension directory before (re-)installing. Pull request #1576

by Jeremy Hinegardner.

* Regenerate test CA certificates with appropriate extensions. Pull

request #1611 by rhenium.

* Rubygems does not terminate on failed file lock when not superuser. Pull

request #1582 by Ellen Marie Dash.

* Fix tar headers with a 101 character name. Pull request #1612 by Paweł

Tomulik.

* Add Gem.platform_defaults to allow implementations to override defaults.

Pull request #1644 by Charles Oliver Nutter.

* Run Bundler tests on TravisCI. Pull request #1650 by Samuel Giddins.

=== 2.6.4 / 2016-04-26

Minor enhancements:

* Use Gem::Util::NULL_DEVICE instead of hard coded strings. Pull request #1588

by Chris Charabaruk.

* Use File.symlink on MS Windows if supported. Pull request #1418

by Nobuyoshi Nakada.

Bug fixes:

* Redact uri password from error output when gem fetch fails. Pull request

#1565 by Brian Fletcher.

* Suppress warnings. Pull request #1594 by Nobuyoshi Nakada.

* Escape user-supplied content served on web pages by `gem server` to avoid

potential XSS vulnerabilities. Samuel Giddins.

=== 2.6.3 / 2016-04-05

Minor enhancements:

* Lazily calculate Gem::LoadError exception messages. Pull request #1550

by Aaron Patterson.

* New fastly cert. Pull request #1548 by David Radcliffe.

* Organize and cleanup SSL certs. Pull request #1555 by James Wen.

* [RubyGems] Make deprecation message for paths= more helpful. Pull

request #1562 by Samuel Giddins.

* Show default gems when using "gem list". Pull request #1570 by Luis

Sagastume.

Bug fixes:

* Stub ordering should be consistent regardless of how cache is populated.

Pull request #1552 by Aaron Patterson.

* Handle cases when the @@stubs variable contains non-stubs. Pull request

#1558 by Per Lundberg.

* Fix test on Windows for inconsistent temp path. Pull request #1554 by

Hiroshi Shirosaki.

* Fix `Gem.find_spec_for_exe` picks oldest gem. Pull request #1566 by

Shinichi Maeshima.

* [Owner] Fallback to email and userid when owner email is missing. Pull

request #1569 by Samuel Giddins.

* [Installer] Handle nil existing executable. Pull request #1561 by Samuel

Giddins.

* Allow two digit version numbers in the tests. Pull request #1575 by unak.

=== 2.6.2 / 2016-03-12

Bug fixes:

* Fix wrong version of gem activation for bin stub. Pull request #1527 by

Aaron Patterson.

* Speed up gem activation failures. Pull request #1539 by Aaron Patterson.

* Fix platform sorting in the resolver. Pull request #1542 by Samuel E.

Giddins.

* Ensure we unlock the monitor even if try_activate throws. Pull request

#1538 by Charles Oliver Nutter.

=== 2.6.1 / 2016-02-28

Bug fixes:

* Ensure `default_path` and `home` are set for paths. Pull request #1513

by Aaron Patterson.

* Restore but deprecate support for Array values on `Gem.paths=`. Pull

request #1514 by Aaron Patterson.

* Fix invalid gem file preventing gem install from working. Pull request

#1499 by Luis Sagastume.

=== 2.6.0 / 2016-02-26

Minor enhancements:

* RubyGems now defaults the `gem push` to the gem's "allowed_push_host"

metadata setting.Pull request #1486 by Josh Lane.

* Update bundled Molinillo to 0.4.3. Pull request #1493 by Samuel E. Giddins.

* Add version option to gem open command. Pull request #1483 by Hrvoje

Šimić.

* Feature/add silent flag. Pull request #1455 by Luis Sagastume.

* Allow specifying gem requirements via env variables. Pull request #1472

by Samuel E. Giddins.

Bug fixes:

* RubyGems now stores `gem push` credentials under the host you signed-in for.

Pull request #1485 by Josh Lane.

* Move `coding` location to first line. Pull request #1471 by SHIBATA

Hiroshi.

* [PathSupport] Handle a regexp path separator. Pull request #1469 by

Samuel E. Giddins.

* Clean up the PathSupport object. Pull request #1094 by Aaron Patterson.

* Join with File::PATH_SEPARATOR in Gem.use_paths. Pull request #1476 by

Samuel E. Giddins.

* Handle when the gem home and gem path arent set in the config file. Pull

request #1478 by Samuel E. Giddins.

* Terminate TimeoutHandler. Pull request #1479 by Nobuyoshi Nakada.

* Remove redundant cache. Pull request #1482 by Eileen M. Uchitelle.

* Freeze `Gem::Version@segments` instance variable. Pull request #1487 by

Ben Dean.

* Gem cleanup is trying to uninstall gems outside GEM_HOME and reporting

an error after it tries. Pull request #1353 by Luis Sagastume.

* Avoid duplicated sources. Pull request #1489 by Luis Sagastume.

* Better description for quiet flag. Pull request #1491 by Luis Sagastume.

* Raise error if find_by_name returns with nil. Pull request #1494 by

Zoltán Hegedüs.

* Find_files only from loaded_gems when using gemdeps. Pull request #1277

by Michal Papis.

=== 2.5.2 / 2016-01-31

Bug fixes:

* Fix memoization of Gem::Version#prerelease? Pull request #1125 by Matijs van

Zuijlen.

* Handle trailing colons in GEM_PATH, by Damien Robert.

* Improve the Gemfile `gemspec` method, fixing #1204 and #1033. Pull request

#1276 by Michael Papis.

* Warn only once when a gemspec license is invalid. Pull request #1414 by Samuel

E. Giddins.

* Check for exact constants before using them, fixing Ruby bug #11940. Pull

request #1438 by Nobuyoshi Nakada.

* Fix building C extensions on Ruby 1.9.x on Windows. Pull request #1453 by Marie

Markwell.

* Handle symlinks containing ".." correctly. Pull request #1457 by Samuel E.

Giddins.

Minor enhancements:

* Add `--no-rc` flag, which skips loading `.gemrc`. Pull request #1329 by Luis

Sagastume.

* Allow basic auth to be excluded from `allowed_push_host`. By Josh Lane.

* Add `gem list --exact`, which finds gems by string match instead of regex. Pull

request #1344 by Luis Sagastume.

* Suggest alternatives when gem license is unknown. Pull request #1443 by Samuel

E. Giddins.

* Print a useful error if a binstub expects a newer version of a gem than is

installed. Pull request #1407 by Samuel E. Giddins.

* Allow the (supported) s3:// scheme to be used with `--source`. Pull request

#1416 by Dave Adams.

* Add `--[no-]post-install-message` to `install` and `update`. Pull request #1162

by Josef Šimánek.

* Add `--host` option to `yank`, providing symmetry with `pull`. Pull request

#1361 by Mike Virata-Stone.

* Update bundled Molinillo to 0.4.1. Pull request #1452 by Samuel E. Giddins.

* Allow calling `build` without '.gemspec'. Pull request #1454 by Stephen

Blackstone.

* Add support for `source` option on gems in Gemfile. Pull request #1355 by

Michael Papis.

* Function correctly when string literals are frozen on Ruby 2.3. Pull request

#1408 by Samuel E. Giddins.

=== 2.5.1 / 2015-12-10

Bug fixes:

* Ensure platform sorting only uses strings. Affected binary installs on Windows.

Issue #1369 reported by Ryan Atball (among others).

Pull request #1375 by Samuel E. Giddins.

* Revert PR #1332. Unable to reproduce, and nil should be impossible.

* Gem::Specification#to_fullpath now returns .rb extensions when such a file

exists.Pull request #1114 by y-yagi.

* RubyGems now handles Net::HTTPFatalError instead of crashing.Pull

request #1314 by Samuel E. Giddins.

* Updated bundled Molinillo to 0.4.0.Pull request #1322, #1396 by Samuel E.

Giddins.

* Improved performance of spec loading by reducing likelihood of loading the

complete specification.Pull request #1373 by Aaron Patterson.

* Improved caching of requirable filesPull request #1377 by Aaron Patterson.

* Fixed activation of gems with development dependencies.Pull request #1388

by Samuel E. Giddins.

* RubyGems now uses the same Molinillo vendoring strategy as Bundler.Pull

request #1397 by Samuel E. Giddins.

* Fixed documentation of Gem::Requirement.parse.Pull request #1398 by

Juanito Fatas.

* RubyGems no longer warns when a prerelease gem has prerelease dependencies.

Pull request #1399 by Samuel E. Giddins.

* Fixed Gem::Version documentation example.Pull request #1401 by Guilherme

Goettems Schneider.

* Updated documentation links to https://.Pull request #1404 by Suriyaa

Kudo.

* Fixed double word typo.Pull request #1411 by Jake Worth.

=== 2.5.0 / 2015-11-03

Major enhancements:

* Added the Gem::Licenses class which provides a set of standard license

identifiers as set by spdx.org. This is now used by the

Gem::Specification#license attribute to try to standardize (though not

enforce) licenses set by gem authors.

Pull request #1249 by Kyle Mitchell.

Minor enhancements:

* Use Molinillo as the resolver library.This is the same resolver as used by

Bundler.Pull request #1189 by Samuel E. Giddins.

* Add `--skip=gem_name` to Pristine command.Pull request #1018 by windwiny.

* The parsed gem dependencies file is now available via Gem.gemdeps following

Gem.use_gemdeps.Pull request #1224 by Hsing-Hui Hsu, issue #1213 by

Michal Papis.

* Moved description attribute to recommended for Gem::Specification.

Pull request #1046 by Michal Papis

* Moved `Gem::Indexer#abbreviate` and `#sanitize` to `Gem::Specification`.

Pull request #1145 by Arthur Nogueira Neves

* Cache Gem::Version segments for `#bump` and `#release`.

Pull request #1131 by Matijs van Zuijlen

* Fix edge case in `levenshtein_distance` for comparing longer strings.

Pull request #1173 by Richard Schneeman

* Remove duplication from List#to_a, improving from O(n^2) to O(n) time.

Pull request #1200 by Marc Siegel.

* Gem::Specification.add_specs is deprecated and will be removed from version

3.0 with no replacement.To add specs, install the gem, then reset the

cache.

* Gem::Specification.add_spec is deprecated and will be removed from version

3.0 with no replacement.To add specs, install the gem, then reset the

cache.

* Gem::Specification.remove_spec is deprecated and will be removed from version

3.0 with no replacement.To remove specs, uninstall the gem, then reset the

cache by calling Gem::Specification.reset.

* Call Array#compact before calling Array#uniq for minor speed improvement in

the Gem::Specification#files method.

Pull request #1253 by Marat Amerov.

* Use stringio instead of custom String classes.

Pull request #1250 by Petr Skocik.

* Use URI#host instead of URI#hostname to retain backwards compatibility with

Ruby 1.9.2 and earlier in util library.

Pull request #1288 by Joe Rafaniello.

* Documentation update for gem sources.

Pull request #1324 by Ilya Vassilevsky.

* Documentation update for required_ruby_version.

Pull request #1321 by Matt Patterson.

* Documentation update for gem update.

Pull request #1306 by Tim Blair.

* Emit a warning on SRV resolve failure.

Pull request #1023 by Ivan Kuchin.

* Allow duplicate dependencies between runtime and development.

Pull request #1032 by Murray Steele.

* The gem env command now shows the user installation directory.

Pull request #1343 by Luis Sagastume.

* The Gem::Platform#=== method now treats a nil cpu arch the same as 'universal'.

Pull request #1356 by Daniel Berger.

* Improved memory performance in Gem::Specification.traverse.Pull request

#1188 by Aaron Patterson.

* RubyGems packages now support symlinks.Pull request #1209 by Samuel E.

Giddins.

* RubyGems no longer outputs mkmf.log if it does not exist.Pull request

#1222 by Andrew Hooker.

* Added Bitrig platform.Pull request #1233 by John C. Vernaleo.

* Improved error message for first-time RubyGems developers.Pull request

#1241 by André Arko

* Improved performance of Gem::Specification#load with cached specs.Pull

request #1297 by Samuel E. Giddins.

* Gem::RemoteFetcher allows users to set HTTP headers.Pull request #1363 by

Agis Anastasopoulos.

Bug fixes:

* Fixed Rake homepage url in example for Gem::Specification#homepage.

Pull request #1171 by Arthur Nogueira Neves

* Don't crash if partially uninstalled gem can't be found.

Pull request #1283 by Cezary Baginski.

* Test warning cleanup.

Pull request #1298 by Samuel E. Giddins.

* Documentation fix for GemDependencyAPI.

Pull request #1308 by Michael Papis.

* Fetcher now ignores ENOLCK errors in single threaded environments. This

handles an issue with gem installation on NFS as best we can. Addresses

issue #1176 by Ryan Moore.

Pull request #1327 by Daniel Berger.

* Fix some path quoting issues in the test suite.

Pull request #1328 by Gavin Miller.

* Fix NoMethodError in running ruby processes when gems are uninstalled.

Pull request #1332 by Peter Drake.

* Fixed a potential NoMethodError for gem cleanup.

Pull request #1333 by Peter Drake.

* Fixed gem help bug.

Issue #1352 reported by bogem, pull request #1357 by Luis Sagastume.

* Remove temporary directories after tests finish.Pull request #1181 by

Nobuyoshi Nokada.

* Update links in RubyGems documentation.Pull request #1185 by Darío Hereñú.

* Prerelease gem executables can now be run.Pull request #1186 by Samuel E.

Giddins.

* Updated RubyGems travis-ci ruby versions.Pull request #1187 by Samuel E.

Giddins.

* Fixed release date of RubyGems 2.4.6.Pull request #1190 by Frieder

Bluemle.

* Fixed bugs in gem activation.Pull request #1202 by Miklós Fazekas.

* Fixed documentation for `gem list`.Pull request #1228 by Godfrey Chan.

* Fixed #1200 history entry.Pull request #1234 by Marc Siegel.

* Fixed synchronization issue when resetting the Gem::Specification gem list.

Pull request #1239 by Samuel E. Giddins.

* Fixed running tests in parallel.Pull request #1257 by SHIBATA Hiroshi.

* Fixed running tests with `--program-prefix` or `--program-suffix` for ruby.

Pull request #1258 by Shane Gibbs.

* Fixed Gem::Specification#to_yaml.Pull request #1262 by Hiroaki Izu.

* Fixed taintedness of Gem::Specification#raw_require_paths.Pull request

#1268 by Sam Ruby.

* Fixed sorting of platforms when installing gems.Pull request #1271 by

nonsequitur.

* Use `--no-document` over deprecated documentation options when installing

dependencies on travis.Pull request #1272 by takiy33.

* Improved support for IPv6 addresses in URIs.Pull request #1275 by Joe

Rafaniello.

* Spec validation no longer crashes if a file does not exist.Pull request

#1278 by Samuel E. Giddins.

* Gems can now be installed within `rescue`.Pull request #1282 by Samuel E.

Giddins.

* Increased Diffie-Hellman key size for tests for modern OpenSSL.Pull

request #1290 by Vít Ondruch.

* RubyGems handles invalid config files better.Pull request #1367 by Agis

Anastasopoulos.

=== 2.4.8 / 2015-06-08

Bug fixes:

* Tightened API endpoint checks for CVE-2015-3900

------------------------------------------------------------------------------

RubyGems installed the following executables:

/Users/xlsn0w/.rvm/rubies/ruby-2.2.2/bin/gem

Ruby Interactive (ri) documentation was installed. ri is kind of like man

pages for ruby libraries. You may access it like this:

ri Classname

ri Classname.class_method

ri Classname#instance_method

If you do not wish to install this documentation in the future, use the

--no-document flag, or set it as the default in your ~/.gemrc file. See

'gem help env' for details.

RubyGems system software updated

XLsn0wdeMac-mini:~ xlsn0w$ sudo gem install -n /usr/local/bin cocoapods

Fetching: nanaimo-0.2.3.gem (100%)

Successfully installed nanaimo-0.2.3

Fetching: xcodeproj-1.4.3.gem (100%)

Successfully installed xcodeproj-1.4.3

Fetching: cocoapods-1.2.0.gem (100%)

Successfully installed cocoapods-1.2.0

Parsing documentation for nanaimo-0.2.3

Installing ri documentation for nanaimo-0.2.3

Parsing documentation for xcodeproj-1.4.3

Installing ri documentation for xcodeproj-1.4.3

Parsing documentation for cocoapods-1.2.0

Installing ri documentation for cocoapods-1.2.0

Done installing documentation for nanaimo, xcodeproj, cocoapods after 6 seconds

3 gems installed

XLsn0wdeMac-mini:~ xlsn0w$ pod --version

1.2.0

XLsn0wdeMac-mini:~ xlsn0w$