Centos cannot find the environment variable -bash: ls: command not found (pro test)

#Enter the command in the system and report the following error:

[root@a1 work]# ll
-bash: ls: command not found

#Temporary solution:
export PATH = / usr / local / sbin: / usr / local / bin: / sbin: / bin: / usr / sbin: / usr / bin: / root / bin

The

export PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

 

#Permanent solution:

export PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

or
echo "export PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/roobo/server/mysql/bin:/root" >>/etc/profile

#Enable environment variables

source /etc/profile

Source: https://www.cnblogs.com/nulige/p/10451392.html