Getting the message from the kernel [LWN.net]

Getting the message from the kernel

Posted Jun 22, 2007 21:24 UTC (Fri) by im14u2c (subscriber, #5246)
In reply to: Getting the message from the kernel by giraffedata
Parent article: Getting the message from the kernel

Hmmm... there's a tradeoff. Verbose error messages are very useful for the beginner, or for obscure error messages that happen very rarely. Terse error messages are more efficient, especially for errors that occur often.

Compare "permission denied" to "Your currently active user id, 'im14u2c', does not have write permission on the file '/tmp/xyzpdq'. This file is owned by 'im14u2c', but the user write permission bit on the file is not set. Please consult the 'chmod' man page."

The latter is very friendly to a new user. Just awesome. But, it would get real old real quick. And, depending on the context, the advice implied by the error message (in this case, chmod +w is implied) might be wrong advice. (For example, what if the file in question is an RCS controlled file that isn't checked out?) Perhaps a settable "user expert level" needs to be specified to indicate how chatty the system should be?

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Getting the message from the kernel

Posted Jun 23, 2007 2:16 UTC (Sat) by giraffedata (subscriber, #1954) [Link]

I don't think it gets old like you think it would. To know, you'd have to try it for a while. I use a lot of software that prints out 5 line error messages on a terminal (because I wrote the code) and it really doesn't bother me. And consider that a lot of programs respond to the most casual error of them all -- fat-fingering -- by not issuing an error message at all but just dumping the full command syntax on the terminal. This seems to be quite popular.

Incidentally, I've found it's rarely a good idea to give advice on how to fix it in the message; the best you can do is to describe the problem. Same is true for a message manual -- the complete set of advice would be a textbook.

And I've tried the expert/novice thing (as a user), and that doesn't work. You're never expert enough that you know all the errors. But maybe something that avoids issuing the same verbose message frequently.

But really, that's all beside the point because we're talking about kernel messages. The kernel isn't interactive -- these things go primarily in a log thousands of lines long.