一、pip是什么

• pip是Python的包安装程序
• 也可以说pip是Python标准库的一个包，只不过这个包可以管理Python标准库之中其它的包
• pip 是一个命令行程序。 安装 pip 后，会向系统添加一个 pip 命令，该命令可以从命令提示符运行

二、pip的使用

• 命令行输入pip + 回车，出现使用说明

  [ych@2ec71362f5e6 ~/Python-3.6.4]$ pipUsage:pip <command> [options]Commands:install                     #安装软件包download                    #下载包uninstall                   #卸载包freeze                      #输出已安装的包(带版本号)list                        #已安装的包;show                        #显示包的详细信息check                       #验证已安装的包是否有兼容选项config                      #管理本地和全局配置search                      #在pypi中搜索包cache                       #检查和管理匹配的库index                       Inspect information available from package indexes.wheel                       Build wheels from your requirements.hash                        Compute hashes of package archives.completion                  A helper command used for command completion.debug                       Show information useful for debugging.help                        Show help for commands.General Options:-h, --help                  Show help.--debug                     Let unhandled exceptions propagate outside the main subroutine, instead of logging them to stderr.--isolated                  Run pip in an isolated mode, ignoring environment variables and user configuration.-v, --verbose               Give more output. Option is additive, and can be used up to 3 times.-V, --version               Show version and exit.-q, --quiet                 Give less output. Option is additive, and can be used up to 3 times (corresponding to WARNING, ERROR, and CRITICAL logginglevels).--log <path>                Path to a verbose appending log.--no-input                  Disable prompting for input.--proxy <proxy>             Specify a proxy in the form [user:passwd@]proxy.server:port.--retries <retries>         Maximum number of retries each connection should attempt (default 5 times).--timeout <sec>             Set the socket timeout (default 15 seconds).--exists-action <action>    Default action when a path already exists: (s)witch, (i)gnore, (w)ipe, (b)ackup, (a)bort.--trusted-host <hostname>   Mark this host or host:port pair as trusted, even though it does not have valid or any HTTPS.--cert <path>               Path to PEM-encoded CA certificate bundle. If provided, overrides the default. See 'SSL Certificate Verification' in pipdocumentation for more information.--client-cert <path>        Path to SSL client certificate, a single file containing the private key and the certificate in PEM format.--cache-dir <dir>           Store the cache data in <dir>.--no-cache-dir              Disable the cache.--disable-pip-version-checkDon't periodically check PyPI to determine whether a new version of pip is available for download. Implied with --no-index.--no-color                  Suppress colored output.--no-python-version-warningSilence deprecation warnings for upcoming unsupported Pythons.--use-feature <feature>     Enable new functionality, that may be backward incompatible.--use-deprecated <feature>  Enable deprecated functionality, that will be removed in the future.