If you're running a modern desktop version of Linux such as Ubuntu, the graphical interface should come with a tool to help you open ISO files, extract contents, and add to them. For example, in the current version of Ubuntu, right-clicking on a .iso file gives a menu that allows you to "Open With Disk Image Mounter." This tool allows you to add, remove, or change files inside the .iso as if it were any other directory. This is likely the easiest way to add files.

If this does not work for you, or if you only have access to the terminal, you can mount an iso file in most linux distributions. As an illustrative example, open the terminal and try the following:

First create a blank mount directory. Many popular Linux distributions will require the 'sudo' command to change system files. The 'sudo' command will likely prompt you for your password before continuing.
``` sh
sudo mkdir /media/mydisk
```

Next, mount your iso file with the '-o loop' option. Obviously, change the line to point to your ISO file and mount location.
```sh
sudo mount ~/<mydisk>.iso /media/mydisk -o loop
```

From here, you can navigate to the directory you chose (for example /media/mydisk) and add your files. In the terminal this would normally use the copy command:
```sh
cp myFile /media/mydisk
```

When you're finished adding your files, you can unmount the ISO file.
```sh
sudo umount /media/mydisk
```
spam fails_task lang_mismatch pii not_appropriate hate_speech sexual_content quality toxicity humor helpfulness creativity violence