一、安装
1、打开命令后
cd /usr/local/bin
如果你把它放在系统的 PATH 目录中，你就能在全局访问它。也可在第3步移动到bin目录。
2、然后执行安装
curl -sS https://getcomposer.org/installer | php
执行不了就直接下载 也是一样的
https://getcomposer.org/download/
3、接下来
sudo mv composer.phar composer
现在只需要运行 composer 命令就可以使用 Composer 而不需要输入 php composer.phar。
4、修改权限
sudo chmod a+x composer
二、查看composer版本
在命令行中输入：composer -V
或者：composer -version
sugardeMacBook-Pro:htdocs sugar$ composer -V
Composer version 1.10.5 2020-04-10 11:44:22
三、更新composer版本
一条命令即可更新：composer self-update
sugardeMacBook-Pro:htdocs sugar$ composer self-update
Updating to version 2.0.11 (stable channel).
Downloading (100%)
Use composer self-update --rollback to return to version 1.10.5
sugardeMacBook-Pro:htdocs sugar$ composer -V
Composer version 2.0.11 2021-02-24 14:57:23
