Sudo in Bash

[daved2424]

I am trying to write a simple bash file. One of the lines has sudo at the beginning which of course requires the user to input their sudo password. Is there a way to run the script without having to type in the sudo password?

[3rdalbum]

There is a way to add the script to the "sudoers" file so it won't prompt for a password to run the script. I am not sure of the syntax required for this.

The other method is to change the owner of the script so that root owns it, and then set the "setuid" flag on it. This means that the script will always run as the file's owner, i.e. root.

If you enable Advanced Permissions in Nautilus for the root user (gksudo gconf-editor; then apps > nautilus), then open a root file browser and get Properties for the script, you can change the owner and add the setuid ability.

[Nepherte]

Depending on the situation (for example, if it's a script that has to run at boot or a cron script), you can remove the sudo because it is executed as root already.

[daved2424]

If you enable Advanced Permissions in Nautilus for the root user (gksudo gconf-editor; then apps > nautilus), then open a root file browser and get Properties for the script, you can change the owner and add the setuid ability.

Are you able to explain this in a little more detail, I don't quite follow what I have to do.

[Slim Odds]

There is a way to add the script to the "sudoers" file so it won't prompt for a password to run the script. I am not sure of the syntax required for this.

The "sudoers" files is a who file, not a what file. Meaning that it specifies who has privileges.

You don't usually need to change sudoers, you just add users to the admin group (which is already specified in sudoers).

[trlkly]

Are you able to explain this in a little more detail, I don't quite follow what I have to do.

I can give it a shot.

1. Use Alt-F2 to open the Run dialog box.
2. Type in "gksudo gconf-editor" (without the quotes) and press Enter.
3. Enter your password (if necessary)
4. Double click apps, scroll down and double-click nautilus, and then click preferences.
5. In the right pane, scroll down until you see show_advanced_permissions. Put a checkmark in its box.

Now, any time you want to change the setuid of a file, run "gksudo nautilus" (using ALT-F2 again).

----

I personally think it would be easier for you to do it all in a terminal, since you obviously know bash. Just cd to the directory that has the file, and then run the following two commands

sudo chown root file
sudo chmod ug+s file

----

Either way you choose, if you ever want to edit the file again, you'll have to open it as root. Run "gksudo gedit /path/to/file", either in a terminal, or with ALT-F2. (replace gedit with your favorite editor. In a terminal, you could also use sudo instead of gksudo.)

[geirha]

The other method is to change the owner of the script so that root owns it, and then set the "setuid" flag on it. This means that the script will always run as the file's owner, i.e. root.

For security reasons, the setuid bit is not honored for scripts, only binary executables...

[daved2424]

That's great everyone. Thank you so much for your help.

[trlkly]

For security reasons, the setuid bit is not honored for scripts, only binary executables...

Seriously? As in, Ubuntu thinks it knows what's best for me and won't let me do what I want to do? That's a Microsoft move, if ever I heard one.

[geirha]

Seriously? As in, Ubuntu thinks it knows what's best for me and won't let me do what I want to do? That's a Microsoft move, if ever I heard one.

Not really Ubuntu. Linux in general. And also many other unix implementations disable setuid for scripts due to security holes.