if i double click on a JPG in Ubuntu, it opens up whatever picture viewer is default, just like windows.
That's not what mikedt is referring to. Automatically opening a JPEG in the default image viewer is not the same thing as
executing a JPEG. It's the image viewer that's being executed in this scenario, not the image FILE.
i don't believe executable exists in Linux--everything is a file!
Nope! Want a quick, very brief, and not all-inclusive lesson on Linux file attributes?
Every file--and this includes directories, because they're files, too--can have three types of permissions, for three sets of users: read/write/execute for user/group/others. So let's say you have a bash script saved as a file named
do_this in your home directory, and its permissions look like this:
Code:
-rwxr-xr-x 1 nick users 248600 2013-01-17 22:45 do_this
See the
rwx? Those are the permissions for you (
user), and they signify read, write, and execute. Then see the two
r-xs? Those are for
group and
others, and they signify read and execute permission only. You can do anything you want to this file, including editing it or deleting it, while everyone else can look at its contents and can execute it, but they can't modify or delete it.
Now our college used and we were required to have our own version (trial) of WinNT 4 and Win2K and i do know the Guest account cannot even set the system time! much less change sensitive info.
Just keep in mind that [just about] anything micro$oft has is [probably] a rip-off, and [usually] a very POOR implementation, of something that originated in *nix.
a 'user' in Linux (i do not recall there being sub-groups in *nix such as guest, power user, and so on just user and root)
*nix has always...always provided for different levels of authority, everything from who could write to tape drives to who could log in only on a terminal and not the server. Again, anything m$ has likely originated in UNIX.
has more power. a 'user' can use his own user password (Ubuntu does not set a separate root password in its installer ) to sudo anything. there is no security when a person can simply use a generic user password to gain even temporary root priviledge, which can be dangerous in itself. but i don't see too many Linux users complaining about problems the way Windows does.
No, that's not how it works. Only a user who has been granted the right to use
sudo can use it. Typically, that person would be the one in charge of administering the system.
Ubuntu and its offspring decided that making it harder to enable a true root login would lead to less catastrophe from windows converts. While I certainly see their point, I still think it's a stupid, unnecessary step. As I've said elsewhere, as soon as I install any *buntu or derivative on a new computer, I give root a password AND I enable root logins. I'm a big girl. I don't need hand holding at this point! :laugh:
Which is something Windows does by default. all software runs with admin/root privileges. Although MS have tried to stop that. 
Appications are certainly executable on Linux, e.g. Chrome. Just that they don't usually have any file suffix. .bin might be used sometimes, to indicate a binary/executable file.
