If we all had to learn, read and try everything for ourselves without being able to ask questions to validate our understanding, there wouldn't be much point to this forum.
Switchless is switchless only in its final form. A switchless installer typically runs an installation program with certain switches, you just don't see them because they're incorporated into the switchless installer.
A program's installer MAY take switches to instruct the program in how to handle its operation. But the program must be written to look for and use certain switches. You can't just throw a
/s switch at any program and expect it to run silently. The program must be written to use the switch. Depending on the program and how it was compiled, the switch for a silent installation could be
/s or
-s or
/silent or
/qn or
/qb or whatever. You get the idea.
A program might be written to not display a welcome screen or ask you to accept a EULA if it's run with its silent switch. Or it might be written to change its default installation folder with whatever follows a
/dir= switch. Not all programs are written to recognize all (or any) switches. Some will use default settings whenever they're run silently and you cannot specify much else. Others will just not install silently no matter what you do which is why some requests for silent switches or switchless installers go unanswered.
A switchless installer is basically a file that wraps around the original program and contains all of the original program's files and the switches. The writer of the switchless installer needs to figure out what switches to use and incorporate them into the switchless installer. Technically, a switchless installer is a self-extracting archive. When a user runs the switchless installer, it extracts the contents, places them where they need to be and runs the original installation program with the switches it's been configured to use. For example, you might find a switchless installer named
installer1.exe that will run the command
program_a.exe /silent and another (
installer 2.exe) that runs
program_b.exe /qn. You could accomplish the same thing with a batch or cmd file containing the lines
program_a /silent
program_b /qnbut then you would have to deal with placing the original program files in the right folders. It's a lot easier to just use a pre-made switchless installer (available through the abundant generosity of some members) and let it do all of the work.
Switches and switchless installers only control certain aspects of an installation. It would be diffilcult, for example, to use switches to specify the installation folder, whether or not to display welcome screens, whether to create desktop shortcuts, which skin to use, the speed something should run at, which dictionary to use, text color, etc. Instead, many programs house those details in separate settings files or in the registry. When you install manually, the program stores your responses. When you change a program's settings after installation, those data stores are updated with the new current values. Usually the only way to figure all of that out is to install the program manually and see what changes in the registry or in the program's folder. Then you could write a routine in the switchless installer that sets those things when the program is installed but each user will have their own preferences. The emphasis is on getting the software installed silently and suppressing the installation screens. The rest can be set by the individual user when they run the application.
There are programs that will record your mouse movements, clicks and keystrokes to duplicate those actions during an unattended installation. As you say, they "go next next next and finish". All of the installation windows open as though you were running a normal manual installation but a macro provides the responses in your absence. It's not the same as a switchless or silent installation, but it is unattended and accomplishes the same thing. This arrangement is good for programs that don't accept switches.
Switchless installers are usually run from runonce. Addons are switchless installers with yet another layer of code that allows them to be run from winnt.sif as a hotfix or update.
I'm still relatively new to all of this and this is only what I've gleened in the last few months. If anyone has any corrections or cares to add anything, please feel free to do so.
Ray