Ubuntu – Is the difference between sudo and gksu the same as the difference between sudo -i and sudo -s

command linegksusudo

Is the difference between sudo cmd and gksu cmd, the same as the difference
between starting a shell with sudo -i and sudo -s?

… or put another way,
Is sudo cmd the same as sudo -i cmd
and gksu cmd the same as sudo -s cmd?

EDIT: Based on what I read on an Ubuntu Documentation Page where it says:

You should never use normal sudo to start graphical applications as root.  
You should use gksudo (kdesudo on Kubuntu) to run such programs. gksudo sets  
HOME=~root, and copies .Xauthority to a tmp directory. This prevents files  
in your home directory becoming owned by root.  
(AFAICT, this is all that's special about the environment of the started   
 process with gksudo vs. sudo).

The "AFAICT" doen't really give me full confidence that there is nothing more to it.

(..a belated UPDATE: I tested his commemnt today (2 months later) about:
"This prevents files in your home directory becoming owned by root."
All files I created via sudo/gksu were all owned by "root", and the group was "root".)

I've read parts of the info sudo and noticed the -i and -s seem to be doing the same thing as the AFAICT environment issue…
but I hit overload.. so I've asked my question here.

PS.. My question is not about sudo vs gksu
.. It is more about: Is gksu the same as sudo -s
.. and if not, how do they differ?

Best Answer

gksu is basically a graphical frontend for sudo that allows graphical command to be run without the need to run an X terminal emulator and using su directly. It's effectively just a GTK+ skin for the superuser commands.

So if you wanted to run a GUI based program as root, you would invoke it with gksu cmd, rather than sudo cmd, which is used for invoking console programs as root.

Related Solutions

Ubuntu – the difference between gksudo and gksu

Both files point to the same place:

$ ls -l /usr/bin/gksudo 
lrwxrwxrwx 1 root root 4 2010-09-27 18:23 /usr/bin/gksudo -> gksu

... gksudo is symlinked to gksu. But this doesn't mean they do the same things, far from it.

Applications can detect the command used to run it. This is typically argv[0] in C-style languages or $0 in Bourne-style shell scripts. The application can look at that and in this case, actually it changes how it works. The first indication of this is in the man gksu page:

gksu  is  a  frontend  to  su  and gksudo is a frontend to sudo.

If you look in the source (apt-get source gksu) for run_mode, you'll see how it detects this:

  { /* support gksu_sudo_run */
    gchar *myname = g_path_get_basename (argv[0]);
    if (!strcmp(myname, "gksudo"))
      run_mode = SUDO_MODE;
    g_free (myname);
  }

You can override this with the --su-mode/-w and --sudo-mode/-S arguments (so you can run equivalent commands without needing the gksudo symlink... But that's up to you.

If you want to know how these "modes" really differ, there's only a bit of escaping in gksu. You need to follow it into libgksu. This is the library that actually checks permissions before handing off to the system.

If no mode is specified (eg you call gksu without arguments) by the time it reaches libgksu, it will check Gconf (as Stefano points out) and if it still can't decide, it'll default to the su mode.

Ubuntu – Difference between ‘dir’ and ‘ls’ terminal commands

dir and ls are part of coreutils and dir is almost the same as ls, just with different default options.

The GNU Core Utilities are the basic file, shell and text manipulation utilities of the GNU operating system. These are the core utilities which are expected to exist on every operating system.

info dir says:

dir is equivalent to ls -C -b; that is, by default files are listed in columns, sorted vertically, and special characters are represented by backslash escape sequences.

Oh and there is also vdir! info vdir says:

vdir is equivalent to ls -l -b; that is, by default files are listed in long format and special characters are represented by backslash escape sequences.

Most likely dir exists for backwards compatibility or due to historical reasons.

Best Answer

Related Solutions

Ubuntu – the difference between gksudo and gksu

Ubuntu – Difference between ‘dir’ and ‘ls’ terminal commands

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