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by **Linux Frank** » Tue Mar 04, 2003 2:34 pm

Okay I wanted to play around with the DMA settings under RH 8.0. As mention on the Ogle site for less jerky play back. However I can get nothing on hdparm. I get a Bash shell error stating it cannot find that command.

Does this sound familiar to anyone, or do I need to do something special to play with this command? It appears in man pages.

by **Void Main** » Tue Mar 04, 2003 3:01 pm

Did you "su -"? It's in /sbin:

# /sbin/hdparm

If it's not there then you don't have the hdparm RPM installed.

by **Linux Frank** » Tue Mar 04, 2003 5:10 pm

Well I did not know that. There is a difference between su and su -. Would it be possible for someone to explain this for me.

And when should I use su and su -. Does the dash release even more root commands and therefore should only be used when absolutely necessary?

by **Void Main** » Tue Mar 04, 2003 5:17 pm

$ man su

says that the "-" makes the shell a "login shell". What that means is it will load the environment files as if you logged in as that user. Without the "-" it does not load the login files. Normal users do not have "/sbin" and "/usr/sbin" in their "PATH" where root does. So if you do an "su -" you will have "/sbin" and "/usr/sbin" in your PATH where if you just do an "su" you will not (unless you have added them to your user PATH).

A little more info:
$ info su

by **Linux Frank** » Tue Mar 04, 2003 9:57 pm

I swear I read up on information and call up man and info pages like they are the holy grail.

I think my brain is still adjusting to the opening up of possibilities that Linux offers me, so I slip a little here and there (trying to learn too much too quick).

Thanks for pointing me in the right direction (well giving me the answer in this case), It did not occur to me to man su (I have no idea why, it's usually where I go first).

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hdparm - missing?

hdparm - missing?

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