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I would like to monitor the messages generated when I boot my Mac, similar to what you on a *nix box. Is there key-combo to press/hold that will let me do this?

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up vote 7 down vote accepted

You have to press cmd + v upon startup to see the boot output. Press this right after the chime.

If you want to make that permanent, you should probably do something along the lines of:

sudo nvram boot-args="-v"

To undo the above:

sudo nvram boot-args=

in the Terminal. (/Applications/Utilities/

note: I haven’t tested the above commands, but I’m sure a google query will help you there if you want to make it permanent.

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I can hardly wait to try this. I hate staring at the apple on boot. – chiggsy Nov 24 '10 at 3:29
Why? What's wrong with it? – JBRWilkinson Feb 12 '11 at 9:55

If you want to see the boot messages after the boot occurred, log in and run sudo dmesg in

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