Check Installing CentOS 6.2 on VMware post.
more /proc/meminfo
– display memory usage in MB
free -m
– display CPU info & count
awk '/model name/ {ORS=""; count++; if ( count == 1 ) print $0; } END { print " : " count "\n" }' /proc/cpuinfo
– display hard disk info & usage
df -h
– check Linux kernel is 32 bit or 64 bit
uname -m
– finding out hardware details
dmidecode | more
– sort unix processes on ps by highest memory usage
ps -eo pmem,pcpu,rss,vsize,args | sort -k 1 -r | more
– list processes
ps -ef
– get package version
rpm -qa | grep mysql*
– clear mail queue
rm -f /var/spool/mqueue/*
– show total size of each directory inside /path
ls -d /path/*/ | xargs -r du -hs