In my catalina.out I have this error
/opt/tomcat/bin/catalina.sh: 1: eval: Syntax error: Unterminated quoted string
I think this means that a string is declared with a quotation mark (") but it doesn't have the closing quotation mark, but I don't find the error.
Any suggestions to find the error?
I use tomcat 8.5.3.32 and I only add this to catalina.sh
JAVA_OPTS="$JAVA_OPTS -Xms2048m -Xmx4096m -XX:PermSize=512m -XX:MaxPermSize=512m"
It's best to restore the default catalina.sh file and never change it.
Instead, create a setenv.sh file in the same directory, and do all of your configuration there. That file will not be overwritten by a future tomcat upgrade, and will continue to keep your personal configuration changes going forward.
For the problem at hand: Evaluate if your $JAVA_OPTS already contains quotes - e.g. through a directory that contains a space. And make sure the whole expanded line is properly formatted.
But an even better fix: You don't want to make the changes you're doing in JAVA_OPTS, but in CATALINA_OPTS (here's why). Set its value - in setenv.sh - to
CATALINA_OPTS="$CATALINA_OPTS -Xms2048m -Xmx4096m -XX:PermSize=512m -XX:MaxPermSize=512m"
(or follow the other recommendation from my linked answer and use identical memory settings for -Xms and -Xmx)