OK, so I'm a moron, let's get that out of the way first.
I was trying to upgrade FC4 to FC5 and I thought I'd be bold, so I used: yum upgrade
This worked hard for a while downloading headers etc. but eventually it failed due to dependency problems with initscript and kudzu.
So I googled further and found this site:http://fedoraproject.org/wiki/YumUpgradeFaq
Unfortunately, the first thing it says to do is remove kernels 2.6.14 and earlier, so I hit: yum remove kernel2.6.1*
Now I admit that I thought this was dangerous ("how can the OS run with the kernel removed?") but trusted the advice, as forums have always helped me in need.
The command processed for a while deleting everything that depended on the kernel i.e. everything! Now I have no commands (ls, yum, rpm, nautilus, firefox etc.).
By a freak of nature, I just happened to be playing poker online (for real money, small 0.25c thankfully) using W2K in a VM under VMWare. That continues to run fine although all basic linux functions e.g. the main menu fail!
While using another PC to google for a fix, the damn screen saver kicked in, and now won't let me login - I guess I've also lost the s/w for credentials checking, or maybe my logon record itself! To further punish my stupidity, in a cruel joke I can still hear the poker chips being tossed around i.e. the VM is still running quite happily (hope it's not loosing me money).
The only thing I can now interact with is a Ctrl-Alt-F2 terminal, which I'd already logged into (finally I'm lucky). Of course I can't actually do anything with no commands
On condition that I promise never to try anything so stupid in the future, can anyone offer any suggestions for fixing this? I do have two live distro's available that I thought I might be able to use to un-delete the files (the disk has had no activity except the VM which only accesses a fixed sandbox file on disk) but I wouldn't know where to start. With yum do files get really-really deleted or just "flagged"?
Should I stop whizzing into the wind and just start a reinstall?
I have emailed the guy running the wiki to point out this shortcoming.