Take the 2-minute tour ×
Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

I know what the man page has to say about the -K and -k :

‑K

The ‑K (sure kill) option is like ‑k except that it removes the user's cached credentials entirely and may not be used in conjunction with a command or other option. This option does not require a password. Not all security policies support credential caching.

‑k[command]

When used alone, the ‑k (kill) option to sudo invalidates the user's cached credentials. The next time sudo is run a password will be required. This option does not require a password and was added to allow a user to revoke sudo permissions from a .logout file. Not all security policies support credential caching. When used in conjunction with a command or an option that may require a password, the ‑k option will cause sudo to ignore the user's cached credentials. As a result, sudo will prompt for a password (if one is required by the security policy) and will not update the user's cached credentials.

So if there is no need to use a command in conjunction with these options, am i correct in assuming K is always the better option to use rather that k?

share|improve this question
add comment

migrated from stackoverflow.com Jun 27 '13 at 17:59

This question came from our site for professional and enthusiast programmers.

1 Answer

up vote 4 down vote accepted

sudo -K and sudo -k, without a command, do the same thing: they invalidate the user's cached credentials.

sudo -k command ... is different: it ignores the user's cached credentials for the current command, but doesn't invalidate them.

Use -k with a command when you want to run a single command without either using or clobbering your cached credentials. (I'm actually not sure why you'd want to do that, but the capability is there.)

Use either sudo -k or sudo -K if you want to clobber your cached credentials.

Summary:

sudo -k           # clobbers cached credentials
sudo -K           # clobbers cached credentials
sudo -k command   # ignores cached credentials
sudo -K command   # invalid
share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.