blog it! To reset your OS X password without an OS X CD

To reset your OS X password without an OS X CD you need to enter terminal and create a new admin account:

step1: Reboot
Hold apple + s down after you hear the chime.

step2:
When you get text prompt enter in these terminal commands to create a brand new admin account (hitting return after each line):

# mount -uw /
# rm /var/db/.AppleSetupDone
# shutdown -h now

After rebooting you should have a brand new admin account. When you login as the new admin you can simply delete the old one and you’re good to go again!

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Making USB installer from iso to img of usb used

Note: this procedure requires an .img file that you will be required to create from the .iso file you download.

TIP: Drag and Drop a file from Finder to Terminal to "paste" the full path without typing and risking type errors.

Download the desired file

Open the Terminal (in /Applications/Utilities/ or query Terminal in Spotlight)

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Convert the .iso file to .img using the convert option of hdiutil (e.g., hdiutil convert -format UDRW -o ~/path/to/target.img ~/path/to/kubuntu.iso)

Note: OS X tends to put the .dmg ending on the output file automatically.

Run diskutil list to get the current list of devices

Insert your flash media

Run diskutil list again and determine the device node assigned to your flash media (e.g. /dev/disk2)

Run diskutil unmountDisk /dev/diskN (replace N with the disk number from the last command; in the previous example, N would be 2)

Execute sudo dd if=/path/to/downloaded.img of=/dev/rdiskN bs=1m (replace /path/to/downloaded.img with the path where the image file is located; for example, ./ubuntu.img or ./ubuntu.dmg). Using /dev/rdisk instead of /dev/disk may be faster. If you see the error dd: Invalid number `1m', you are using GNU dd. Use the same command but replace bs=1m with bs=1M. If you see the error dd: /dev/diskN: Resource busy make sure the disk is not in use. Start the "Disk Utility.app" and unmount (not eject) the drive.

Run diskutil eject /dev/diskN and remove your flash media when the command completes

Restart you Mac and press alt while the Mac is restarting to choose the USB-Stick

快速几步：

1.把iso转成dmg格式

# hdiutil convert -format UDRW -o ~/path/to/target.img ~/path/to/kubuntu.iso

2. 查找USB有设备盘符

# diskutil list
3. 把USB unmount

# diskutil unmountDisk /dev/diskN
N是查找到u盘 可能是1，2这样的数字

4. 把dmg复制到u盘

# sudo dd if=/path/to/downloaded.img of=/dev/rdiskN bs=1m

If you see the error dd: Invalid number `1m', you are using GNU dd. Use the same command but replace bs=1m with bs=1M. If you see the error dd: /dev/diskN: Resource busy make sure the disk is not in use. Start the "Disk Utility.app" and unmount (not eject) the drive.

5. 弹出U盘

# diskutil eject /dev/diskN

6. 重启时按住Option键，选择usb启动。

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