DSL Ideas and Suggestions :: /boot/cmdline



I wonder if this, or something similar, might be considered for a future release.  I thought it would be useful for a couple of reasons:
1) It would allow a user to more easily customize a CD without the need to remaster (just rebuild the ISO).
2) It would save having to repeat some of the same boot options for every bootloader entry, or typing at boot at all.
3) I don't know, but it seems like there's at least a third good reason.

The theory is this:
All of your boot options, whether entered at the boot prompt or through the bootloader, are saved to /proc/cmdline for use in startup scripts and whatever else the user might find handy.  If there was a simple way for the user to have his own cmdline file outside of the compressed KNOPPIX image, he could put what boot string he wants in that file and it would be appended to /proc/cmdline before the hardware detection and other business gets started.
I haven't found where /proc/cmdline is actually created...I'm guessing it's embedded in one of the boot files?  What i think might work, though, is if there was a piece of script added to /etc/init.d/knoppix-config, just before the CMDLINE variable is set, which checks for the presence of /boot/cmdline (or whatever file is convenient), and appends its contents to /proc/cmdline.

I don't know how useful others might find this, but considering the power of boot options in DSL I think it would be very nice.
/proc/cmdline is part of the proc filesystem. From the Linux kernel documentation

Quote
The proc file system acts as an interface to internal data structures in the kernel. It can be used
to obtain information about the system and to change certain kernel parameters at runtime (sysctl).


/proc/cmdline shows the append options that were passed to the kernel when it was loaded. It is not possible to alter it's contents (echo "blah">>/proc/cmdline will fail). It would be possible to have the contents of /proc/cmdline saved somewhere else, amend that as required and then have DSL's scripts look there instead of /proc/cmdline.

But isn't it is already possible to use custom boot options by editing isolinux.cfg/syslinux.cfg?
If /proc/cmdline can't be modified, then it would be too complicated to mess with...I just thought it would be a simple addition.

However, if editing the cfg file will do the same, then that's super.  I'd looked at it a few times but i thought maybe it was only used for the liveCD "boot:" prompt, which doesn't display in Frugal.   I'll have to check this out.
Thanks.
Quote (mikshaw @ Aug. 01 2005,19:49)
However, if editing the cfg file will do the same, then that's super.  I'd looked at it a few times but i thought maybe it was only used for the liveCD "boot:" prompt, which doesn't display in Frugal.   I'll have to check this out.
Thanks.

isolinux.cfg/syslinux.cfg only works on a rebuilt livecd, not on frugal - I was answering your first point, but didn't make myself clear.

Quote
1) It would allow a user to more easily customize a CD without the need to remaster (just rebuild the ISO).
That's mainly what I'd use it for anyway.  In frugal I can add whatever boot options to Grub.  I was just hoping there was an easy way, when i finally get a Frugal setup I really like, to just burn it to CD (with maybe a couple of path changes) and have the custom boot options in place.  The isolinux.cfg looks like the solution. The mydsl CD script wouldn't work for my current setup...I think it would require me to change the way I use frugal, which i don't want to do at this time.
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