linux安裝composer

https://www.runoob.com/w3cnote/composer-install-and-usage.html
Linux 平台可以使用以下命令來安裝：

1、下載配置文件並安裝

前提條件，已經安裝了php73he mysql8

php73 -r "copy('https://install.phpcomposer.com/installer', 'composer-setup.php');"
php73 composer-setup.php

All settings correct for using Composer
Downloading...

Composer (version 1.9.0) successfully installed to: /usr/share/nginx/composer.phar
Use it: php composer.phar

移動 composer.phar，這樣 composer 就可以進行全局調用：

2、調整php73為 php，

cd usr/bin
cp php73 php

/*
這一步很重要，否則會報錯
/usr/bin/env: php: 沒有那個文件或目錄
*/

mv composer.phar /usr/local/bin/composer

切換為國內鏡像：

3、安裝composer

composer config -g repo.packagist composer https://packagist.phpcomposer.com

更新 composer：

composer selfupdate