set: Tried to change the read-only variable “_” about bass HOT 4 CLOSED

set: Tried to change the read-only variable “_”
# adding MAVEN_HOME=/Library/Maven/Home
set -g -x MAVEN_HOME "/Library/Maven/Home"
# updating PATH=/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/local/git/bin:/usr/local/MacGPG2/bin -> /opt/local/libexec/gnubin:/opt/local/bin:/opt/local/sbin:/Library/Maven/Home/bin:/Users/matt/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/local/git/bin:/usr/local/MacGPG2/bin
set -g -x PATH "/opt/local/libexec/gnubin" "/opt/local/bin" "/opt/local/sbin" "/Library/Maven/Home/bin" "/Users/matt/bin" "/usr/bin" "/bin" "/usr/sbin" "/sbin" "/usr/local/bin" "/usr/local/git/bin" "/usr/local/MacGPG2/bin"
# updating _=/usr/bin/python -> /opt/local/bin/python
set -g -x _ "/opt/local/bin/python"
# adding M2_HOME=/Library/Maven/Home
set -g -x M2_HOME "/Library/Maven/Home"
# adding JAVA_HOME=/Library/Java/JavaVirtualMachines/zulu-8.jdk/Contents/Home
set -g -x JAVA_HOME "/Library/Java/JavaVirtualMachines/zulu-8.jdk/Contents/Home"
# adding TOMCAT_HOME=/Library/Tomcat/Home
set -g -x TOMCAT_HOME "/Library/Tomcat/Home"
# adding GRADLE_HOME=/opt/local/share/java/gradle
set -g -x GRADLE_HOME "/opt/local/share/java/gradle"
# adding JRE_HOME=/Library/Java/JavaVirtualMachines/zulu-8.jdk/Contents/Home
set -g -x JRE_HOME "/Library/Java/JavaVirtualMachines/zulu-8.jdk/Contents/Home"

# updating _=/usr/bin/python -> /opt/local/bin/python