在linux下编译java程序，执行javac编译生成class文件时，在centos7终端输入如，javac hello.java    会提示未找到指令，但用java -verison测试环境变量是没问题的

百度了好久，说的很复杂，重新再linux配置环境变量，输入 vi /etc/profile进入，添加以下代码：

export JAVA_HOME=/usr/local/jdk1.8.0_144

export PATH=$JAVA_HOME/bin:$PATH

export CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar

再测试，最后也没有成功

后来在stackoverflow上看到了这个

84 down vote accepted

You installed the Java Runtime Environment (JRE) only, which does not contain javac. For javac, you have to install the OpenJDK Development Environment. You can install java-devel or java-1.6.0-openjdk-devel, which both include javac.

By the way: you can find out which package provides javac with a yum search, e.g.

su -c 'yum provides javac'

Another note: using yum and openjdk is only one possibility to install the JDK. Many people prefer Sun/Oracle's "original" SDK. See How to install Java SDK on CentOS? and links for alternatives.

大意就是我们用yum来装原生的就行了

在终端输入

yum install java-devel

执行安装

再测试就行了

补充：Vi编辑常用快捷键

复制：ctrl+insert

粘贴：shift+insert

按Esc保存退出编译，shift+zz退出

本文转自：https://blog.csdn.net/yalecaltech/article/details/70158620