安装composer，最好需要有php的软连接。
先执行一下以下命令查看是否php命令已经软连接好了。
[root@68 ~]# which php
/usr/bin/which: no php in (/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin)如果是这样，表示并不能直接使用php。我们这个时候需要对php做软连接。
我的php的路径在/usr/local/php/bin/php。所以命令就是：
ln -sf /usr/local/php/bin/php /usr/local/bin/php然后我再执行一下开头的命令：
代码语言：javascript复制[root@68 bin]# which php
/usr/local/bin/php好了。这样就可以进行安装了。我们仅仅需要下面这一条命令就可以了。
代码语言：javascript复制curl -sS https://getcomposer.org/installer | php -- --install-dir=/usr/local/bin --filename=composer当显示如下效果的时候，就表示安装完成了：
代码语言：javascript复制All settings correct for using Composer
Downloading...
Composer (version 1.3.0) successfully installed to: /usr/local/bin/composer
Use it: php /usr/local/bin/composer这样我们就可以使用composer进行类库安装了。
修改为国内镜像
全局修改
代码语言：javascript复制composer config -g repo.packagist composer https://packagist.phpcomposer.com碰到的问题
phar "/usr/local/bin/composer" has a broken signature错误:
PHP Fatal error: Uncaught exception 'PharException' with message 'phar "/usr/local/bin/composer" has a broken signature' in /usr/local/bin/composer:23
Stack trace:
#0 /usr/local/bin/composer(23): Phar::mapPhar('composer.phar')
#1 {main}
thrown in /usr/local/bin/composer on line 23解决办法：删除文件包，重新安装。
- php缺失
openssl扩展:
Some settings on your machine make Composer unable to work properly.
Make sure that you fix the issues listed below and run this script again:
The openssl extension is missing, which means that secure HTTPS transfers are impossible.
If possible you should enable it or recompile php with --with-openssl解决办法: PHP安装openssl扩展。
- php缺失
zlib扩展:
The zlib extension is not loaded, this can slow down Composer a lot.
If possible, install it or recompile php with --with-zlib
The php.ini used by your command-line PHP is: /usr/local/php/etc/php.ini
If you can not modify the ini file, you can also run `php -d option=value` to modify ini values on the fly. You can use -d multiple times.解决办法: PHP安装zlib扩展。
