Apple/OSX Archives - blog.robert.mcfrazier.com

Fix permission denied on OSX dd to SD card

Posted on June 15, 2013 by Robert McFrazier

Posted in Apple/OSX, Linux, Raspberry PI 5 Comments

I was installing RedSleeve onto my new Raspberry PI and needed to fix a problem when writing the image onto the SD card. I kept getting “Permission denied” error messages, when issuing the command to write the image.

Let’s see…

Am I using sudo? Yes I am.

Is the disk unmount before trying to write to it? Yes it is.

Ok everything seems to be in order. Let’s check my command

sudo xz -cd raspi-v2-redsleeve-cli-0.3.img.xz | dd of=/dev/rdisk1 bs=8388608

Ah, Ha!! sudo is not being applied to the part of the command after the pipe.

Ok, how to solve this. We can use the “-c” switch on the bash command to apply sudo to the entire command string.

sudo bash -c 'xz -cd raspi-v2-redsleeve-cli-0.3.img.xz | dd of=/dev/rdisk1 bs=8388608'

Now my SD is being written to.

Taking a screenshot on Mac OSX

Posted on March 18, 2013 by Robert McFrazier

Posted in Apple/OSX, Helpers Leave a comment

Taking a screenshot on Mac OSX, the name of the text file with the instructions for taking screenshots on my desktop, because I can’t seem to remember the key sequence. I thought this would be a good topic for a blog post, for myself and others that need a quick helper on the subject.

Screenshot of entire display

Take a screenshot of the display, and save it as a file on the desktop.
If you have multiple monitors you will have multiple files saved to your desktop.
1. Command-Shift-3
2. The snapshot sound will play, and the file will be on the desktop
OSX snapshot sound OSX snapshot sound

Take a screenshot of the screen, and save it to the clipboard.
1. Command-Control-Shift-3
2. The snapshot sound will play, and the screenshot will be saved to the clipboard
OSX snapshot sound OSX snapshot sound

Screenshot of a window

Take screenshot of a window and save to desktop.
1. Command-Shift-4
2. Cursor changes to crosshair
3. Hit the space bar
4. Click the window you want to take a screenshot
5. The snapshot sound will play, and the file will be on the desktop
OSX snapshot sound OSX snapshot sound

Take screenshot of a window and save to clipboard.
1. Command-Control-Shift-4
2. Cursor changes to crosshair
3. Hit the space bar
4. Click the window you want to take a screenshot
5. The snapshot sound will play, and the screenshot will be saved to the clipboard
OSX snapshot sound OSX snapshot sound

Screenshot an area

Take screenshot of an area of the screen and save to desktop.
1. Command-Shift-4
2. Cursor changes to crosshair
3. Select an area to screenshot
4. When the mouse button is released the snapshot sound will play, and the file will be on the desktop
OSX snapshot sound OSX snapshot sound

Take screenshot of area and save to clipboard.
1. Command-Control-Shift-4
2. Cursor changes to crosshair
3. Select an area to screenshot
4. When the mouse button is released the snapshot sound will play, and the screenshot will be saved to the clipboard
OSX snapshot sound OSX snapshot sound

Clear DNS Cache on OSX 10.8 Mountain Lion

Posted on September 2, 2012 by Robert McFrazier

Posted in Apple/OSX, Helpers Leave a comment

How to clear the DNS cache on OSX 10.8 Mountain Lion.

In a terminal window type the following:

sudo killall -HUP mDNSResponder

Per Apple,

OS X keeps a local cache of resolved DNS queries for a time defined by the DNS server, but sometimes it may be necessary to reset the cache immediately and re-query a DNS server.

Convert line endings from the OSX command line

Posted on June 18, 2012 by Robert McFrazier

Posted in Apple/OSX, Helpers Leave a comment

Converting line endings… gotta love it.

I received a text file today that I needed to parse it to automate building several hundred WordPress accounts, more on that at another time, and the file had DOS line endings. I knew there had to be a way to correct this that did not require the installation of any new software or libraries.

Heck, I’m on a *nix based OS. How about “tr”

“tr” will translate characters for me, and it is available from the OSX command line.

Hmmm.. how about.