How to make boot output verbose?

Question

I use to enjoy watching my red hat then debian then ubuntu machine boot, the boot process was not hidden from my view, now it is, in most of all distros, now, I know I can somehow connect a terminal to a serial port and "see" the boot process, but I'm not sure what happens after the GUI starts, also pressing the ESC key during boot in ubuntu shows some info, what I'm looking for, no big deal if I have to setup another computer just for the task, is to vew all the stderr or whatever the name for that is, like a constantly refreshed dmesg command. is that possible? if so, can I have it in a "stay on top" terminal (which btw I know how to setup)

Solution

There are two parts in this. One is the grub part which is hidden by the boot screen. You can enable its output for textual consummation by changing the line GRUB_CMD_LINE_LINUX_DEFAULT in /etc/default/grub on Ubuntu machines and remove quiet splash:

#GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
GRUB_CMDLINE_LINUX_DEFAULT=""

run update-grub after this for it to take effect.

This will give you text mode message until X takes over you screen. You can change that as well but then you would have to start X by hand. If I want to see those messages hidden by X, I change to the console with Ctrl+Alt+F7 (on Mint, Ubuntu might be different).

Comments

[Lambert]

Are you looking for the information in /var/log/boot.log?

[Anthony Geoghegan]

I too like the verbose text output when a GNU/Linux system boots up. I recently configured GRUB on my Ubuntu laptop to boot in text mode. However, I'm not at home so can't provide the details. In any case, the boot process is so fast nowadays that most of the output scrolls by too quickly to read -- even on my 7 year old laptop!

[ortegacomputacion]

Yes Mr Lmbert, and no, I was looking for that but in a dynamic way, to be ble to "see" the kernel humming, I don't know if the standard output for errors or kernel messages goes to /dev/null after the gui starts, if so, I would like to redirect it somehow to a fancy terminal I can check at will sometimes,

[ortegacomputacion]

Thanks Mr Anthon, that was an easy mod, now I can really "see" my computer booting, with all the "OKs" and the ocassional "failed", and I love it, but I'm still hungry for more under the hood stuff, like I told Mr Lambert. perhaps I could catch all the trash going to /dev/null and redirect it to a autoscrollling terminal somehow and then let it go? nobody wants a huge file sitting there for nothing, I also know the system log viewer, but it is somehow static, and you have to search for the parts you want, or browse a tree, what I was looking for is a bunch of text showing info about the kernel

[Anthon]

@ortegacomputacion I don't think there is that much going to /dev/null, but you could replace that device with a normal file and just use that.

[ortegacomputacion]

Thanks, will try that, it looks like I'm being forced to learn python! lol, there is soo much going on behind our backs when using a computer, I think I miss the old days, now it's all hidden and you can see just what you need, oops, perhaps that's a feature for the common user, but what about the curious george? I would sign up for a developer emailing list, or kernel stuff, but I consider myself not worthy of it. lol