Os X on Aaron West's technology blog

How to Retrieve Your Wi-Fi Password on Mac

Thu, 23 Jul 2015 08:00:00 -0500

I don’t generally forget the password for Wi-Fi networks I use, mainly because I use 1Password to store all secrets. But, I ran across the ability to retrieve the password, in plain text, from the OS X Keychain of an SSID I’ve previously connected with. Not a huge amount of utility to this but it’s interesting the capability exists.

In the command below I read the the keychain and hone-in on just the password portion. Replace <SSID_NAME> with the name of of a valid SSID you’ve connected with in the past. Keep in mind case sensitivity matters. You can leave off | grep password and retrieve the whole item too. This command requires authentication so you’ll be asked to enter your username and password.

Flushing DNS Cache on Mac OS X

Mon, 20 Jul 2015 16:43:00 -0500

Below are the various Bash commands needed to flush DNS on Mac OS X. There are several different versions of the commands depending on which version of OS X in use. Ensure you are selecting the command appropriate for your OS. HT to OSXDaily for additional explanations on what is happening under the covers.

Flush DNS on OS X Yosemite 10.10.4 and Newer

When 10.11.x aka ‘El Capitan’ ships this command should continue to function. This set of commands will flush all DNS caches on OS X including Multicast DNS and Unicast DNS.

Generating SSH Keys on Mac OS X

Sun, 19 Jul 2015 16:41:00 -0500

Generating an SSH key without a password. For example, for passphraseless old school Hadoop clusters. This is generally done from within a users home directory such as /Users/username on Mac.

ssh-keygen -t rsa -P ""

Generating an SSH key with a password. This is generally done from within a users home directory such as /User/username on Mac.

ssh-keygen -t rsa

How to copy a generated SSH key to the Mac clipboard. This is arguably better than manually copying and pasting.