terwer@terwer-PC:~$ cd /opt/*tomcat*/bin

terwer@terwer-PC:/opt/apache-tomcat-9.0.13/bin$ sudo chmod u+x ./*.sh

提示无JAVA_HOME，但是我已经设置了JAVA_HOME

terwer@terwer-PC:/opt/apache-tomcat-9.0.13/bin$ sudo ./startup.sh

[sudo] terwer 的密码：

Neither the JAVA_HOME nor the JRE_HOME environment variable is defined

At least one of these environment variable is needed to run this program

编辑 setclasspath.sh，在顶部添加下面的内容

export JAVA_HOME=/usr/lib/jvm/jdk1.8.0_191

export JRE_HOME=/usr/lib/jvm/jdk1.8.0_191/jre

此时已经可以了

terwer@terwer-PC:/opt/apache-tomcat-9.0.13/bin$ sudo ./startup.sh

Using CATALINA_BASE:   /opt/apache-tomcat-9.0.13

Using CATALINA_HOME:   /opt/apache-tomcat-9.0.13

Using CATALINA_TMPDIR: /opt/apache-tomcat-9.0.13/temp

Using JRE_HOME:        /usr/lib/jvm/jdk1.8.0_191/jre

Using CLASSPATH:       /opt/apache-tomcat-9.0.13/bin/bootstrap.jar:/opt/apache-tomcat-9.0.13/bin/tomcat-juli.jar

Tomcat started.