This post shows the steps to create a multiboot cd with multiple Linux distributions or tools.

For example, I created a recovery / disaster case cd with the following tools:
Clonezilla (to clone/recover disks and partitions)
Gparted (partition editior with GUI)
Trinity Rescue Kit (linux distribution for recovery and repair operations on Windows machines)

The Multicd script tool (https://multicd.us/) can be used to generate the image following these steps:

Prerrequisite

You must have mkisofs or genisoimage previously installed

$ sudo apt-get install genisoimage

Download MultiCD script

You can either use the git tool to get it…

$ git clone git://github.com/IsaacSchemm/MultiCD.git

or download the master.zip file…

$ cd /tmp
$ wget https://github.com/IsaacSchemm/MultiCD/archive/master.zip
$ unzip master.zip
$ cd MultiCD-master

Get the ISOs you want to combine

Download the ISO images of the distributions and tools you want to add to the multiboot cd and place them in the MultiCD-master folder

Linux – Create multiboot CD combining multiple ISO images

Run the MultiCD script

$ sudo ./multicd.sh

(must be ran as root)

$ sudo ./multicd.sh
Cleaning up - removing symlinks to files in current directory
Made a link named auto.clonezilla.iso pointing to clonezilla.iso
Made a link named auto.gparted.iso pointing to gparted.iso

multicd.sh 20170609
Extracting ISO images with mount; will build multicd; UID 0.

Clonezilla
GParted Live
Trinity Rescue Kit
Memtest86+

Continuing in 2 seconds - press Ctrl+C to cancel
Copying files for each plugin...
Copying Clonezilla (auto.clonezilla.iso)...
Copying GParted Live (auto.gparted.iso)...
Copying Trinity Rescue Kit...
Unpacking and copying SYSLINUX files...
Writing isolinux.cfg...
/tmp/MultiCD-master/multicd-working/boot/isolinux/cz-auto.clonezilla.cfg
/tmp/MultiCD-master/multicd-working/boot/isolinux/cz-auto.clonezilla.cfg
Building CD image...
Warning: Creating ISO-9660:1999 (version 2) filesystem.
Warning: ISO-9660 filenames longer than 31 may cause buffer overflows in the OS.
Size of boot image is 4 sectors -> No emulation
 ...
 99.51% done, estimate finish Fri Nov  3 09:24:25 2017
Total translation table size: 2048
Total rockridge attributes bytes: 7110
Total directory bytes: 22994
Path table size(bytes): 178
Max brk space used 1b000
301487 extents written (588 MB)
Running isohybrid...
isohybrid gave an error status of 126. The ISO might not work on a flash drive.
Cleaning current directory...
Cleaning up - removing symlinks to files in current directory

Use your newly created image

Now, you can find your multiboot ISO under the “build ” folder…

$ ls build
multicd.iso

to boot from it!

Linux – Create multiboot CD combining multiple ISO images