我试图执行
(base) [sebastianr@user ~]$ php
bash: php: command not found
(base) [sebastianr@user ~]$ sudo ln -s /opt/llamp/bin/php /usr/bin/php
[sudo] password for sebastianr:
ln: failed to create symbolic link '/usr/bin/php': File exists
该文件在 usr/bin/ 目录中，我需要做什么？