wget <SCRIPT URL> -O – | sh –
This command executed on most *nix systems will download a remote script and execute it all in one fell swoop. How convenient, right? Sure, so long as you know what the script does and trust from whom it came. But not so much if it’s something one of your developers found on a message board and wanted to “give a whirl.” What could possibly go wrong? Be prepared with a glass of Alka Seltzer when you spring this on your unsuspecting sysadmin victim, because heartburn is sure to follow.
mkfs <DISK PARTITION>
Ahh, the make filesystem command for (re)formatting a disk partition, again for most *nix systems. While this one may require superuser permissions to execute, it’s far too easy for even an experienced and careful user to type in the wrong partition name (wait, was it /dev/c0d1s8 or /dev/c0d0s8 that that I needed to reformat?) One incorrect letter can blow away all sorts of important stuff. This could be the subject of the next Friday the 13th movie: Jason Reformats the Disk with Our Financials.
These, of course, are just a small sample of commands the mere mention of which could make your favorite sysadmin clutch his or her chest. Any of you admins out there want to add more? Or do you have methods in place to prevent such disasters? Please share in the comments.