Linux command line

Linux command line is a string passed to the kernel by the bootloader.
When using LILO this is what you type after the name of the image. When using Choose-OS you will be prompted for a command line when you start the image with space instead of enter.
You will then see your default command line (i.e. one given in the configuration file with cmdline=my_commandline option). You can edit this command line or clear it by pressing esc.

There are a lot of command line options depending on the drivers you have. Some common options are:

Choose-OS will automagically append 'BOOT_IMAGE=<image_name>' to the command line. 'auto' will also be appended when started with the default command line.