php centos 环境变量 切换版本

背景

要使用支付宝sdk  支付宝sdk最新的需要7.2版本php并且

要安装componser 

php -v
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PHP 5.2.17p1 (cli) (built: May 13 2020 16:10:32) 
Copyright (c) 1997-2010 The PHP Group
Zend Engine v2.2.0, Copyright (c) 1998-2010 Zend Technologies
    with Zend Optimizer v3.3.3, Copyright (c) 1998-2007, by Zend Technologies
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rm -f /usr/bin/php
ln -sf /www/server/php/72/bin/php /usr/bin/php
php -v
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PHP 7.2.33 (cli) (built: Aug 11 2020 15:38:39) ( NTS )
Copyright (c) 1997-2018 The PHP Group
Zend Engine v3.2.0, Copyright (c) 1998-2018 Zend Technologies
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