# free -m
             total       used       free     shared    buffers     cached
Mem:         64268       4960      59307         64          0        135
-/+ buffers/cache:       4824      59443
Swap:         2047          0       2047

# ps -eo rss | awk '{sum += $1}; END {print sum/1024/1024}'
2.54199

# free -h
             total       used       free     shared    buffers     cached
Mem:           62G        13G        48G        80M         0B        77M
-/+ buffers/cache:        13G        48G
Swap:         2,0G         4K       2,0G

# ps -eo vsize | awk '{sum += $1}; END {print sum/1024/1024}'
25.8389

# ps -eo rss | awk '{sum += $1}; END {print sum/1024/1024}'
1.24232

# ps -eo pmem,rss,vsize,args | grep tomcat
 1.7  1158608 22684408 java -classpath /usr/share/tomcat/bin/bootstrap.jar:/usr/share/tomcat/bin/tomcat-juli.jar:/usr/share/java/commons-daemon.jar -Dcatalina.base=/usr/share/tomcat -Dcatalina.home=/usr/share/tomcat -Djava.endorsed.dirs= -Djava.io.tmpdir=/var/cache/tomcat/temp -Djava.util.logging.config.file=/usr/share/tomcat/conf/logging.properties -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager org.apache.catalina.startup.Bootstrap start