Quickly (soft-)reboot skipping hardware checks

/sbin/kexec -l /boot/$KERNEL --append="$KERNELPARAMTERS" --initrd=/boot/$INITRD; sync; /sbin/kexec -e
If you are doing some tests which require reboots (e. g. startup skripts, kernel module parameters, ...), this is very time intensive, if you have got a hardware with a long pre-boot phase due to hardware checks. At this time, kexec can help, which only restarts the kernel with all related stuff. First the kernel to be started is loaded, then kexec -e jumps up to start it. Is as hard as a reboot -f, but several times faster (e. g. 1 Minute instead of 12 on some servers here).
Sample Output
# /sbin/kexec -l /boot/vmlinuz- --append='root=/dev/sda3 resume=/dev/sda2 console=ttyS1,115200n8 console=tty0 elevator=cfq pci=nomsi max_scsi_luns=2048 max_scsi_report_luns=2048 selinux=0 splash=silent showopts' --initrd=/boot/initrd-
# sync
# /sbin/kexec -e

By: olorin
2009-08-03 07:36:49

What Others Think

Very sexy command ! Useful after kernel upgrade.
GouNiNi · 643 weeks ago
This should get you rebooted with the same kernel and parameters that you're running with now: kexec -l /boot/vmlinuz-$(uname -r) --append="$(dmesg | fgrep -m 1 'Command line' | cut -f2- -d:)" --initrd=/boot/initrd.img-$(uname -r) && sync && kexec -e
HorsePunchKid · 642 weeks and 4 days ago
a very detailed and meticulous lesson, it really has a lot of value, I will learn a lot thanks.luke yavin jacket
alexhales · 1 week and 6 days ago

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

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