Encountered during installation of various software problems under Linux

1. maven installation process, discovered modify the profile file, ls command can not be used, Internet search found:

2. Install jdk in Linux, you need to configure the environment variables, Hershey jdk installed after the installation of Tomcat, did not give Tomcat configuration environment variable, catalinahome have a (relatively doubt), maven configuration environment variable.
FIG:

#set Java Environment
Export the JAVA_HOME = / usr / Java / jdk1.8.0_211
Export the CLASSPATH = .: $JAVA_HOME/jre/lib/rt.jar:$JAVA_HOME/lib/dt.jar: $JAVA_HOME/lib/tools.jar export MAVEN_HOME=/usr/local/maven/apache-maven-3.6.1 export PATH=$PATH: $JAVA_HOME/bin:$MAVEN_HOME/bin