Unix useful Commands and traces

*You also can use the " free -m" to see the memory status in megabytes. Change the 'm' to 'k' or 'g' to see it in kilobytes and gigabytes respectively.
*You can use the "watch free" command to see the memory usage in real time. But the display in only in KBs.
* Use the command "fdisk -l" to list all drives you have. This will list the USB devices you have connected as well. It gives the details of partiotions on each disk.

**Try running every command u learn using 'strace' eg 'strace ls' - that would show you the system calls that a command makes and would give you more insights into the working of system/kernel. it would be helpful if you u wish to take system programming.
similarly 'ltrace ' would show you library calls a program makes.

i would suggest to use the "lshw" command, this will give all the info about all the h/w present on your computer