Why maven settings.xml file is not there?

settings.xml is not required (and thus not autocreated in ~/.m2 folder) unless you want to change the default settings.

Standalone maven and the maven in eclipse will use the same local repository (~/.m2 folder). This means if some artifacts/dependencies are downloaded by standalone maven, it will not be again downloaded by maven in eclipse.

Based on the version of Eclipse that you use, you may have different maven version in eclipse compared to the standalone. It should not matter in most cases.

Installation of Maven doesn't create the settings.xml file. You have to create it on your own. Just put it in your .m2 directory where you expected it, see http://maven.apache.org/settings.html for reference. The m2eclipse plugin will use the same settings file as the command line.