[arch-general] Broke my system again - device-mapper & readline conflict - best way to fix?

[Baho Utot]

On Fri, 2009-07-10 at 19:26 -0500, David C. Rankin wrote:
> Listmates,
> 
> 	I have more fun in store for this weekend. After testing dmraid-1.0.0rc15, I had downgraded a number of packages that were installed from testing back to there normal versions but had left dmraid-1.0.0rc15 and device mapper from testing. Everything was working fine.
> 
> 	Apparently some packages were moved from testing to extra or another normal repo because all of a sudden I began getting readline...so.6 error (from memory) on boot and was dumped into maintenance mode. In maintenance mode, I remounted to root filesystem rw and then mounted all the partitions and ran pacman -Sy readline (testing is disabled)
> 
> 	After installing the latest readline, my box will not boot. I now gives a readline...so.5 error and never gets to maintenance mode. My question is "What is the best way to try and recover?"
> 
> 	I have two options to work on the archlinux install:
> 
> 	(1) the machine is dual boot with openSuSE so I can boot to suse and then mount the Archlinux filesystem (rw) under /mnt/arch.  I'm not sure what I can do here unless there is a way for me to manually unpack some pacman packages and overwrite the problem files on the Arch install in this configuration; or
> 
> 	(2) boot using the Arch install disk. Here is where I'm a little lost on the recovery procedure. I can manually assemble my raid array after booting to the install disk, but then what next? How would I go about reinstalling the various packages from either testing or extra when I have booted from the install disk?
> 
> 	Thus my need for help. What say the experts? How best to go about fixing the device-mapper readline conflict?
> 

I am using bash as my shell and I was bitten by this bed bug as well. 

This is how I fixed it....

Fetch bash from an archlinux repos

put the bash package some place where you can get to it

boot from arch install/live cd 

chroot to the broken system

pacman -U bash......

reboot