系统是centos6.5
[root@memda www]# composer global require "laravel/installer=~1.1" changed current directory to /root/.composer ./composer.json has been created loading composer repositories with package information updating dependencies (including require-dev) - installing symfony/process (v3.1.3) downloading: failed downloading: failed downloading: failed failed to download symfony/process from dist: the "https://api.github.com/repos/symfony/process/zipball/04c2dfaae4ec56a5c677b0c69fac34637d815758" file could not be downloaded: failed to open stream: no route to host now trying to download from source - installing symfony/process (v3.1.3) cloning 04c2dfaae4ec56a5c677b0c69fac34637d815758 installation failed, deleting ./composer.json. the disk hosting /root/.composer is full, this may be the cause of the following exception [runtimeexception] failed to clone https://github.com/symfony/process.git via https, ssh protocols, aborting. - https://github.com/symfony/process.git error: failed connect to github.com:443; operation now in progress while accessing https://github.com/symfony/process.git/info/refs fatal: http request failed - git@github.com:symfony/process.git ssh: connect to host github.com port 22: no route to host fatal: the remote end hung up unexpectedly require [--dev] [--prefer-source] [--prefer-dist] [--no-plugins] [--no-progress] [--no-update] [--update-no-dev] [--update-with-dependencies] [--ignore-platform-reqs] [--sort-packages] [-o|--optimize-autoloader] [-a|--classmap-authoritative] [--] []...

总是会出现symfony/process下载失败的过程，而且完全查不到原因呀，哭哭哭哭……
回复内容：系统是centos6.5
[root@memda www]# composer global require "laravel/installer=~1.1" changed current directory to /root/.composer ./composer.json has been created loading composer repositories with package information updating dependencies (including require-dev) - installing symfony/process (v3.1.3) downloading: failed downloading: failed downloading: failed failed to download symfony/process from dist: the "https://api.github.com/repos/symfony/process/zipball/04c2dfaae4ec56a5c677b0c69fac34637d815758" file could not be downloaded: failed to open stream: no route to host now trying to download from source - installing symfony/process (v3.1.3) cloning 04c2dfaae4ec56a5c677b0c69fac34637d815758 installation failed, deleting ./composer.json. the disk hosting /root/.composer is full, this may be the cause of the following exception [runtimeexception] failed to clone https://github.com/symfony/process.git via https, ssh protocols, aborting. - https://github.com/symfony/process.git error: failed connect to github.com:443; operation now in progress while accessing https://github.com/symfony/process.git/info/refs fatal: http request failed - git@github.com:symfony/process.git ssh: connect to host github.com port 22: no route to host fatal: the remote end hung up unexpectedly require [--dev] [--prefer-source] [--prefer-dist] [--no-plugins] [--no-progress] [--no-update] [--update-no-dev] [--update-with-dependencies] [--ignore-platform-reqs] [--sort-packages] [-o|--optimize-autoloader] [-a|--classmap-authoritative] [--] []...

总是会出现symfony/process下载失败的过程，而且完全查不到原因呀，哭哭哭哭……
自己解决，忘记修改composer的全局配置了，镜像还是要使用国内的镜像，
composer config -g repo.packagist composer https://packagist.phpcomposer...
好蠢！