File permissions?

[Jim Byrnes]

Fred Roller wrote:
> 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.
>>
>> 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?
>>
>> Thanks,  Jim
>>
>>   
> Jim,
>     Welcome to Ubuntu.  I too have passed files from OS to OS.  There 
> sounds like you have one of three options.  First a quick lesson on 
> permissions in Ubuntu (Linux); and I apologize if this is basic.  A file 
> is read, written, or executed by either the user, a group, or others 
> (aka all others) so if you open a terminal and from command line try the 
> following:
>       
>     froller at metis:~$ touch yourfile
>     froller at metis:~$ ls -l yourfile
>     -rw-r--r-- 1 froller root 0 2009-12-24 23:05 yourfile
>     froller at metis:~$
> 
> If you note the "-rw-r--r--"; this is actually four sets "- | rw- | r-- 
> | r--".  Followed by "froller root" or "user | group". 
> 
> The first set is simply a "category" if you will, "-" is a regular file, 
> "d" would be directory, "l" would be a link, etc. 
> 
> The other three sets "rw- | r-- | r--"  are your permission sets  They 
> are, respectively, the user, the group, and the other.  The user, or 
> owner of the file; indicated by the "froller" can read and write but not 
> execute.  The second set "r--" means anyone in the "root" group, similar 
> to a "workgroup" can, in this case, read the file but not write or execute.
> 
> Back to your question:
> 
> 1. The easiest (and yes, least secure) would be to change the permission 
> of the file to full access for all.
> 
>     sudo chmod 777 yourfile
> 
> I prefer to work with the number method and can explain if you wish; 
> but, this would give you permissions which look like:
> 
>     -rwxrwxrwx 1 froller root 0 2009-12-24 23:05 yourfile
> 
> you can read the manual for more information on chmod:
>    
>     man chmod
> 
> 2. You could change the owner to your Ubuntu user.  If your file starts 
> like:
> 
>     -rw-r--r-- 1 root root 0 2009-12-24 23:05 yourfile
> 
> where "root" owns the file, then:
> 
>     sudo chown froller yourfile
> 
> where froller is your user then the file would look like:
> 
>     -rw-r--r-- 1 froller root 0 2009-12-24 23:05 yourfile
> 
> giving your user read/write access to the file.  Read more on "chown" with:
> 
>     man chown
> 
> 3. Perhaps the simplest solution would be to run jedit as root with:
> 
>     gksu jedit
> 
> Again, be careful of security.  You are running a program with compiling 
> capability as the root user.  Advantage is that permissions are a none 
> issue with this option.
> 
> Hope this helps.  Permissions in Linux becomes real easy with practice 
> so you should catch on quickly.
> 

At my level of knowledge nothing is too basic.  Actually your reply and 
some others are exactly what I was hoping for, some specifics mixed in 
with some general knowledge.

Thanks,  Jim