By default in OS X, when you change an extension for a file, you get a warning. This is somewhat annoying to me, as I do this pretty frequently and have never almost accidentally done so. So to disable, send a FXEnable ExtensionChangeWarning key into com.apple.finder as false: defaults write com.apple.finder FXEnableExtensionChangeWarning -bool false To then undo, simply run with a true key: defaults write com.apple.finder FXEnableExtensionChangeWarning -bool true
-
-
Get Line Numbers With The Less Command
One of the great things about cat is that you can view the contents of a file with line numbers. You do so using the -n option, as follows: cat -n ~/Desktop/myFile Sometimes a file is too big to view though, so you can pipe the output to less, to combine some of the best features of each: cat -n ~/Desktop/myFile | less Obviously, the same thing would work with more: cat -n ~/Desktop/myFile | less You can also do something similar with the grep command and the -n option: grep -n ^ ~/Desktop/myFile | less Enjoy.
-
cd To The Previous Directory
The cd command has lots of fun little shortcuts. One I use frequently is the -. The ~ always takes you to your home directory, but using cd – will take you to the last directory you were in. For example, if you do the following on a Mac: cd ~ Then you do .. (which is a shortcut for the directory above the one you’re in): cd .. Then pwd will show that you’re in /Users. But, if you cd to – again: cd - Now you’re back in your home folder. The – expands to OLDPWD. Quick tip. Nothing more to see here.
-
Disable Unicast ARP Cache Validation In OS X
As of OS X 10.9 (and in many cases more importantly in OS X Server for 10.9 and higher), OS X now performs ARP cache validation when trying to pass traffic over a router. If you are double NAT’d/use redundant gateways then the traffic can be interpreted as network redirection and cause some pretty bad packet loss/latency. You can disable this feature by turning off net.link.ether.net.arp_unicast_lim using sysctl: sysctl -w net.link.ether.inet.arp_unicast_lim=0 That will only disable unicast arp validation until the next reboot. If it fixes a latency problem you’re having then you can go ahead and make it permanent by adding the following line into /etc/sysctl.conf: net.link.ether.inet.arp_unicast_lim=0 If you’re still…
-
Some minor updates to https://krypted.com/
So a few months ago, closing in on 3,000 posts, the database got too big and krypted.com started suffering from innodb corruption, resulting in database outages. While I was able to get the site up, it was using a read-only database that kept me from doing any new articles or updates. It was a strange time in my life, like suddenly being single after living with someone since Y2K (when I started the site). But I got through it and was able to repair the relation… er, site. Now, with a new database that is free from corruption we’re ready to get to 6,000 posts! Also, I had a little…
-
Command Line Firewall Management In OS X 10.10
The tools to automate OS X firewall events from the command line are still stored in /usr/libexec/ApplicationFirewall. And you will still use socketfilterfw there for much of the heavy lifting. However, now there are much more helpful and functional options in socketfilterfw that will allow you to more easily script the firewall. Some tricks I’ve picked up with the Mac Firewall/alf scripting: Configure the firewall fully before turning it on (especially if you’re doing so through something like Casper, FileWave, Munki, or Absolute Manage where you might kick yourself out of your session otherwise). Whatever you do, you can always reset things back to defaults by removing the com.apple.alf.plist file…
-
Bushel: Notes On Unlocking A Locked Device
We’ve all been there, or spoken with someone who’s been there: you’re looking at a locked device and someone doesn’t know the PIN to unlock the device. On an iPad, iPhone, iPod Touch a Mobile Device Management product such as Bushel can unlock that device by resetting the PIN and allowing you to configure a new PIN. It’s kinda’ awesome when someone forgets a PIN they assigned a device, leaves the company or just plain forgets. But, there are a few things we should probably mention about this feature of Bushel: Read More About Unlocking A Locked Device On The Bushel Blog
-
Don’t Use bless To Change Startup Disks Any More In OS X
For a long time, we used the bless command to startup systems to a specific volume in OS X. Back in 2009 I started using the systemsetup command for more and more tasks. These days, I’m being guided to replace all of my bless options in scripts to systemsetup. The easy way to configure your startup volumes using systemsetup is to list the available volumes, set one as the startup volume and then check to see which one is the current volume. The first task is to list the available startup volumes, using the -liststartupdisks option: sudo systemsetup -liststartupdisks You can then set the disk as one that was listed…
-
Bushel: MDM, MAM, MEM, & EMM
Mobile Device Management (MDM) is an additional layer of securing provided to a standard deployment of mobile devices. In the Apple management context, MDM provides our customers with a way to make sure that they can monitor devices, that devices fit within the boundaries of what our customers consider to be good security, making it easier to setup devices (by quickly providing WiFi information, helping to deploy apps, etc) and of course by getting a good inventory of the devices you have out there in the wild. Read More About MDM, MAM, MEM, and EMM At blog.bushel.com
-
Create 10,000 Empty Directories for Testing
The mkdir command is used to create directories. Sometimes, in testing, you need to have a lot of directories. So, you can use the following command to create 10,000 5 digit directories, named 00001 to 10000: mkdir $(printf '%05d\n' {1..10000})