Retrieve the system spec from command line in linux

Use this following commands for CPU and Memory:

#CPU-INFO
cat /proc/cpuinfo
#MEM-INFO
cat /proc/meminfo

Also during the boot process many  messages are written to the message buffer, which you can view using "dmesg". e.g. do this:

dmesg >~/dmesg.out

Also this shell script provides a brief info about the hardware spec:
http://www.pixelbeat.org/scripts/sysinfo