php composer 如何升级

composer 是一个php的代码依赖管理工具，你在项目中声明依赖，composer 会帮你完成安装。composer 的升级命令是  composer self-update

# Author: www.phpjiaocheng.com


[root@localpc ~]#composer version --no-plugins --no-scripts --version
Do not run Composer as root/super user! See https://getcomposer.org/root for details
Composer version 1.4.2 2017-05-17 08:17:52
[root@localpc ~]#
[root@localpc ~]#
[root@localpc ~]#
[root@localpc ~]#composer self-update
Updating to version 1.10.9 (stable channel).
   Downloading (100%)
Use composer self-update --rollback to return to version 1.4.2
[root@localpc ~]#
[root@localpc ~]#
[root@localpc ~]#composer version --no-plugins --no-scripts --version
Do not run Composer as root/super user! See https://getcomposer.org/root for details
Composer version 1.10.9 2020-07-16 12:57:00