Shell script for creating Virtual Disks in linux

The shell script for creating Virtual Disks in linux-general Linux technology-Linux programming and kernel information. The following is a detailed description. #! /Bin/bash
# Ramdisk. sh
# A "ramdisk" is a segment of system RAM memory
# + That acts as if it were a filesystem.
# Its advantage is very fast access (read/write time ).
# Disadvantages: volatility, loss of data on reboot or powerdown.
# Less RAM available to system.
#
# What good is a ramdisk?
# Keeping a large dataset, such as a table or dictionary on ramdisk
# + Speeds up data lookup, since memory access is much faster than disk access.
E_NON_ROOT_USER = 70 # Must run as root.
ROOTUSER_NAME = root
MOUNTPT =/mnt/ramdisk
SIZE = 2000 #2 K blocks (change as appropriate)
BLOCKSIZE = 1024 #1 K (1024 byte) block size
DEVICE =/dev/ram0 # First ram device
Username = 'id-nu'
If ["$ username "! = "$ ROOTUSER_NAME"]
Then
Echo "Must be root to run \" 'basename $0 '\"."
Exit $ E_NON_ROOT_USER
Fi
If [! -D "$ MOUNTPT"] # Test whether mount point already there,
Then # + so no error if this script is run
Mkdir $ MOUNTPT # + multiple times.
Fi
Dd if =/dev/zero of = $ DEVICE count = $ SIZE bs = $ BLOCKSIZE # Zero out RAM device.
Mke2fs $ DEVICE # Create an ext2 filesystem on it.
Mount $ DEVICE $ MOUNTPT # Mount it.
Chmod 777 $ MOUNTPT # So ordinary user can access ramdisk.
# However, must be root to unmount it.
Echo "\" $ MOUNTPT \ "now available for use ."
# The ramdisk is now accessible for storing files, even by an ordinary user.
# Caution, the ramdisk is volatile, and its contents will disappear
# + On reboot or power loss.
# Copy anything you want saved to a regular directory.
# After reboot, run this script again to set up ramdisk.
# Remounting/mnt/ramdisk without the other steps will not work.
Exit 0