4. "df" is a command that displays the amount of disk space available on the file system containing each file name argument. Read the man page of "df command. Run the command df" to find out how many disk blocks are available and how many are in use. Does the sum of these equals the total number of disk blocks on the disk? If not, explain why there is a difference. Next run the command "df -i" to find out how many inodes are available and in use. Now create a new file with just a few characters in it, and again run "df" and "df -i' commands. Explain the effect of creating this new file. Now increase the size of this new file by entering a large number 5000) of characters, and again run "df" and "df -i"commands. Explain the effect of increasing the size of the new file