File permissions?

[Jim Byrnes]

Tim Frost wrote:
> Jim,
> 
> The reply from Fred Roller may shed some light.
> 
> Ubuntu uses 'sudo xxx' to do 'xxx' as root.  You may need it here.  When
> sudo asks for a password, supply *your* password
> 
> On Thu, 2009-12-24 at 21:09 -0600, Jim Byrnes wrote:
>> I've been using Ubuntu for about two weeks now and am starting to get 
>> used to it.  However, coming from an OS/2\Windows world file permissions 
>> seem to be giving me some grief.
>>
>> Maybe if someone could tell me how to do a couple of specific tasks it 
>> would become clearer to me.  I have Jedit loaded on all three of my 
>> OS's. I have modified some mode files on the other OS's I would like to 
>> use on Ubuntu.  I copied them to a shared folder on Ubuntu but I can't 
>> copy them to /usr/share/jedit/modes which is where Jedit will look for them.
> 
> Most packages support a per-user settings location, in the user home
> directory.  For jedit, this is the directory $HOME/.jedit, which you
> own.  If you put the customised modes in directory $HOME/.jedit/modes,
> you should have them accessible to you, and you can modify them safely.
> This makes them available to you, but not to other users on the Ubuntu
> system.
> 
> To make them available to other users, you need to install the modified
> files in /usr/share/jedit/modes.  Rules for directory permissions are
> more complex than for files:
> * To create or delete a FILE in the directory, I need WRITE permissions
> on the directory (not the file - but rm will warn if I try to remove a
> file I can't write to)
> * to edit a file, I need read/write permissions on the file, but not the
> directory.
> (This is because of the way that linux/unix stores permissions and
> ownership information)
> 
> If you need to put the mode files into /usr/share/jedit/modes, the
> following will allow you to do that:
>   sudo cp -p <my-mode-files> /usr/share/jedit/modes
> 
> Using sudo will allow the copy to change the permissions, and add new
> files into the directory. The '-p' option will preserve permissions
> (including the fact that you own the files) when copying them.  This
> means that you should have the modified files available for all users,
> and you should be able to update them (including copying replacements
> from the other computers) without needing to use sudo [unless you want
> to modify a file that you don't yet own on the ubuntu machine).
> 
> 
>> In that same vein, if I wanted to edit one of those files with Jedit how 
>> could I get Jedit to open it for editing?
> 
> You can give yourself the ability to edit all of the files in the
> directory /usr/share/jedit/modes, with
>   sudo chown $USER /usr/share/jedit/modes/*
> 
> 
>> Thanks,  Jim
>>
> 
> One caveat here:
> Because the files in /usr/share/jedit/modes are part of the jedit
> package, you may find that they get overwritten when you use the package
> management system to upgrade jedit.  For that reason, it is safer to use
> $HOME/.jedit/modes, which won't be touched by a package upgrade.
> 
> Tim
> 
> 
> 

I wondered about the upgrading problem when I finally figured out where 
the install put everything.  I was just starting to realize the reason 
for the stuff under home/ and now you post confirms it for me.

You and other posters have mentioned enviromental variables like $HOME. 
   In OS/2 they are set in config.sys, where are they set in Ubuntu?

Thanks,  Jim