My english may not be the best, but the confusion my posting seems to create lets me assume that is is even worse than I think. *My* confusion came from the context in which my posting was cited.
I was perfectly aware of the meaning of -d and -y. I am using the -d option and avoid activly the -y option *since years*.
I only wanted to emphasize that telling people to open their eyes during d-u and then suggesting the -y option might not be wise, even when done in slighly different contexts.
Does this make clear what I suggested?
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Now, citing my above critics above your suggestion ("apt-get clear") was what I didn't understand.
First it seems completly unrelated to what I said (at least to what I *wanted* to say) and second, now with your additional explaination your suggestion seems to solve a problem that does *not exist* if I understand correctly what you suggested:
There is no *need* to clear whatever. You may "a-g u && a-g d-u -d -y" as often as you wish with as many days in between as you like (if you don't exceed it too far, which would be an other problem) eventually the really completed d-u will work like it would work without all the intermediate download-only d-u_s with exacly the same outcome.
In other words: Your system today it up to date. You make a "a-g u && a-g d-u -d -y" on each of the next three days without installing the downloaded pakages. The fourth day you again make a "a-g u && a-g d-u -d -y", but then, after reading und parsing the output, you install the packages. It will behave as if you omitted the three previous downloads. It does not get installed what you have in your apt cache but but what the *latest* d-u calculates on base of the *installed* and currently available packages.
That's how I do it since years (omitting the -y option ;-) )
Was I misreading your suggestion?
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Unrelated to the above but a general suggestion to d-u. The result *is* related to (not) using the -y option, though:
What I really, exactly use for d-u is:
apt-get update && apt-get dist-upgrade --ignore-hold -d
I even use it if nothing is activly marked "hold" because I issue it using the .bash_history or the tab completition. This way I never ever may forgett about held packages. It is my *default*. I download held packages.
Each "a-g u && a-g d-u --ignore-hold -d" shows me the sid status for my system. (Together with following the forum's update warning section) I am aware of the problems *all the time*, allways inclusive possibly held packages. It is my laziness which prevents me from d-u_ing with install daily.
And when I install, I am aware whether or not I should keep held packages by deleting "--ignore-hold" in the command. If there is nothing held it does not hurt, I don't delete it.
So if I'd suggest a d-u strategy I'd suggested mine, of course, because you *always* get a complete picture and all info you need without any additional ado.
This is the *opposite* of the -y option.