Disk Utility hanging on all user accounts

Question

Hi,
I suspect that my son applied new permissions to enclosed items somewhere and that this is the reason that Disk Utility hangs (doesn't respond) when I start it. As a remedy I repaired permissions while started from an external disk and then applied some command lines that I learned for resetting user account permission (http://discussions.apple.com/thread.jspa?threadID=1655174&tstart=0). But still DU is unresponsive and must be force quit. Additionally I cannot open the DVD tray and Firefox tells me "...update available but you do not have the systems permissions required to install it....".
So I think my user permissions reset was not successful. My question is: did the command line language change from Leopard to SnowLeopard because Terminal gave me some feedback that "-H makes sense only with R" or something to that effect.
Do you have any idea about these things? What's the best way to proceed? Thanks.

Answer 1

Has command line language changed in SnowLeo compared to Leopard?
There are a few changes that reflect the differences between the two OS versions but the vast majority of commands are the same. There are hundreds of commands. Including the flags, switches, & options available for them there are thousands of variations. Plus, characters like spaces, slashes, dashes, & quote marks have special meaning depending on where they appear in the command line so even a minor typo can dramatically change a command into something other than what you want.
Because of this, you should not use a command unless it is specifically recommended for an issue you have explained completely or you have at least a fundamental understanding of command line syntax & the options for a command you are going to use. Each command has a manual page ("man page" for short) that you can access in Terminal by typing the word "man" followed by a space followed by the command name. For example, try "man man" to see the manual page explaining that command.
It would help greatly if you could provide the exact command & flags you used, plus any error messages they generated. Also, "standard procedures" doesn't tell us much since different users consider different things standard.
I suspect your problem is not caused by mis-set permissions, although they may have lead to the condition that caused it. But without more info it is hard to say what the problem is or how to fix it. It might be simplest just to reinstall the OS (which for Snow Leopard is not that big a deal), let Software Update bring it up to current versions, & then deal with any remaining user level permission issues separately.