Boot a Live ISO image using grub.

• having already installed arch based linux system on my pc.
• without using live usb, we can also boot the .ISO file through grub.
• we first need to download the iso file, and then configure our grub menu.
• open grub custom configure file /etc/grub.d/40_custom using text editor.

	$ sudo vim /etc/grub.d/40_custom

• then add the following entry at the bottom:

    menuentry "Title of my ISO file" --class someclassname{ # change someclassname with other name
    set root='(hd2,4)' #change with the main partition of your current OS
    set isofile="/home/jun/Downloads/archlinux.iso" #change with the iso file u want to boot
        set dri="free"
        search --no-floppy -f --set=root $isofile
        probe -u $root --set=abc
        set pqr="/dev/disk/by-uuid/$abc"
        loopback loop $isofile
        linux  (loop)/arch/boot/x86_64/vmlinuz-linux img_dev=$pqr img_loop=$isofile driver=$dri quiet splash vt.global_cursor_default=0 loglevel=2 rd.systemd.show_status=false rd.udev.log-priority=3 sysrq_always_enabled=1 cow_spacesize=2G
    initrd  (loop)/arch/boot/intel-ucode.img (loop)/arch/boot/amd-ucode.img (loop)/arch/boot/x86_64/archiso.img
    } 

• note to replace isofile path to the path of your downloaded iso file.
• and replace the Title of my ISO file with anything you want to show in grub menu.
• then save the file (if using vim press the <ESC> button and then press the : button and write wq and press enter).
• then reload and update the grub.cfg

    # on Arch based distro
    $ sudo grub-mkconfig -o /boot/grub/grub.cfg

    # on ubuntu based distro
    $ sudo update-grub

• and we are done.
• you can restart and choose the iso from grub.