How do I know if user cancelled?

Asked by David D Lowe on 2008-07-02

If a user cancels gksu, how can I retrieve that information programmatically? The exit code stays 0.

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Ubuntu gksu Edit question
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Solved by:
Harvey Muller
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Harvey Muller (hlmuller) said : #1


According to the gksu manpage, the following should be reported:

"On success, gksu will return 0. If an authentication error ocurred, it will exit with error code 3. If the user canceled the dialog or closed the window, it will return error code 2. On other error conditions, gksu will return 1."

Therefore, if the user cancels the dialog or closes the window, gksu "should" return error code 2. If it is not doing this, then something is probably wrong.

To retrieve the error code using a shell script sh or bash), then here is a small shell script sample:


    gksu gedit || echo "gksu gedit erred with code: $?"

The first part "gksu gedit" runs gedit as the superuser. If it errors out, then the second part runs. '||' is the equivalant of 'or'. The second part prints the error message, '$?' is the status, which should be '1' or '2'.

Please return back here to change the status of the question to Solved, if this solves your question.



David D Lowe (flimm) said : #2

That's not in the man page of the gksu I have.

If I run your script and cancel, nothing is printed.
If I run this script using sh

gksu gedit
echo "gksu gedit erred with cod: $?"

I get:
gksu gedit erred with code: 0

Even when I click cancel.
The package of gksu I have installed is 2.0.0-5ubuntu3

Harvey Muller (hlmuller) said : #3

Hi David,

I googled the previous answer, and have confirmed that on Hardy the gksu manpage does not state that. Apologize for that noise.

I'm testing on my ubuntu machine right now, and will report back shortly.


Harvey Muller (hlmuller) said : #4


The gksu implementation used by Ubuntu does not appear to return any error codes. /var/log/auth.log certainly does not contain this information. I've checked other logs on the system and am unable to find related error messages that could be checked.

For what it's worth, here's a link displaying the information I provided in the first post:

It looks like that at one time, gksu did emit error codes.

Best regards,


David D Lowe (flimm) said : #5

Thanks Harvey Muller, that solved my question.

David D Lowe (flimm) said : #6

Thanks for that info. So there's no easy way to find out if gksu cancelled?

Best Harvey Muller (hlmuller) said : #7


There appears to be no way to return the status of an application which was started by gksu. Based on the manpage I found above, it looks like at one time, at least one version of gksu did.

Best regards,


David D Lowe (flimm) said : #8

Thanks Harvey Muller, that solved my question.