前提：仅仅下载testng.jar
不配置环境变量的前提下:
Java -cp "path-tojar/testng.jar:path_to_yourtest_classes" org.testng.TestNG testng.xml
配置环境变量：
export TESTNG_HOME=/home/peng/testng
export CLASSPATH=$CLASSPATH:$TESTNG_HOME/testng-6.8.6beta.jar
目录下执行 java org.testng.TestNG testng.xml
如出现下面错误：
Exception in thread "main" java.lang.NoClassDefFoundError: com/beust/jcommander/ParameterException
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Unknown Source)
at java.lang.Class.privateGetMethodRecursive(Unknown Source)
at java.lang.Class.getMethod0(Unknown Source)
at java.lang.Class.getMethod(Unknown Source)
at sun.launcher.LauncherHelper.validateMainClass(Unknown Source)
at sun.launcher.LauncherHelper.checkAndLoadMain(Unknown Source)
Caused by: java.lang.ClassNotFoundException: com.beust.jcommander.ParameterException
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
... 7 more
则是由于缺少jcommander.jar：http://central.maven.org/maven2/com/beust/jcommander/1.48/jcommander-1.48.jar
下载后在环境变量中添加：
export CLASSPATH=$CLASSPATH:$TESTNG_HOME/jcommander-1.48.jar