Solve the problem that Linux cannot use system commands such as ls\clear after configuring JDK environment variables

Solve the problem that Linux cannot use system commands such as ls\clear after configuring JDK environment variables**

Error description: After CentOS7 installed jdk1.8 in rpm mode, the java environment was configured, and the following error occurred after restarting.

-bash: fg: no job control
-bash: /usr/java/jdk1.8.0_261-amd64/jre/bin: Is a directory

problem causes

Error in jdk configuration information in /etc/profile file

Solution

1. Installing jdk in rpm mode does not need to configure environment variables, delete the jdk configuration information in the /etc/profile file

使用source /etc/profile 命令使修改后的配置文件生效

2. If you need to configure environment variables, you need three steps

1. Use the following command to execute the command that was previously inoperable exportPATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin
2. Change the configuration file to the following

JAVA_HOME=/usr/java/jdk1.8.0_221-amd64
JRE_HOME=$JAVA_HOME/jre	
CLASSPATH=.:$JAVA_HOME/lib:$JRE_HOME/lib
PATH=$JAVA_HOME/bin:$JRE_HOME/bin:$PATH
export JAVA_HOME JRE_HOME CLASSPATH PATH

3. 使用命令 source /etc/profile使配置文件生效

Reference article

Link: https://blog.csdn.net/moonmoonroc/article/details/106590642 .