Shell Script to Check Hard disk Revolutions Per Minute (RPM) Speed

Q: What is RPM of Hard disk?
Ans: RPM Short form for Revolutions Per Minute, RPM is used to help determine the access time on computer hard drives. RPM is a measurement of how many complete revolutions a computer's hard drive makes in a single minute. The higher the RPM, the faster the data will be accessed; for example, if you were comparing two hard drives, one with 5400 RPM and another with