resetting mac password from the command line
This post is not original. I copied it from elsewhere. When I find the original I will reference it here.
hold down command-S on startup.
Run mount -uw /. (fsck -fy is not necessary.)
In 10.7 and later, run:
launchctl load /System/Library/LaunchDaemons/com.apple.opendirectoryd.plist
or in 10.6 and earlier:
launchctl load /System/Library/LaunchDaemons/com.apple.DirectoryServices.plist
Run
passwd username
and reset the password.
Run
reboot
A second way to reset the login password of an account is to use Reset Password.app from the recovery partition:
Hold command-R on startup.
Open Terminal from the Utilities menu.
Run resetpassword, which opens the Reset Password application.
Select the volume and account and reset the password.
A third way is to create a new admin account:
Hold command-S on startup.
Run
mount -uw /
Run
rm /var/db/.AppleSetupDone
Run
reboot
Go through the steps of creating a new account.
Reset the password of the old account from the Users & Groups preference pane.
None of these options resets the password of the login keychain.
If FileVault 2 is enabled, you have to enter a password to start up in single user mode, and you can't use Reset Password.app to reset the password of an account.
Type
fsck -fy
Type
mount -uw /
Type
launchctl load /System/Library/LaunchDaemons/com.apple.DirectoryServices.plist
Type
dscl . -passwd /Users/username password
replacing username with the targeted user and password with the desired password.
reboot