celsobarriga-dot-com » Mac OS X

Enabling AirDrop on older systems

celso — Sun, 06 Nov 2011 21:27:51 +0000

You can enable AirDrop for many older Lion systems at the Terminal command line. Enter:

defaults write com.apple.NetworkBrowser BrowseAllInterfaces 1

After setting the defaults, you’ll need to restart Finder:

killall Finder

Ejecting a stuck CD or DVD on a Mac

celso — Mon, 13 Sep 2010 18:53:12 +0000

If you have a stuck CD or DVD on your Mac, and the desktop icon for the media has disappeared from the desktop so that you can no longer drag it to the trash, you can manually eject the media without rebooting the machine by executing the following command from the Terminal:

drutil tray eject

dyld: shared cached was built against a different libSystem.dylib, ignoring cache

celso — Thu, 13 Aug 2009 16:06:14 +0000

I just upgraded my MacBook Pro’s hard drive to one with a bigger capacity. After restoring the contents from the old drive to the new one using an image created by SuperDuper!, I keep on getting this error every time I launch the Terminal application:

dyld: shared cached was built against a different libSystem.dylib, ignoring cache

After googling around, I found this discussion thread from Apple’s Support Forum on how to fix the error:

sudo update_dyld_shared_cache -force

How to determine DST time changes

celso — Fri, 01 Feb 2008 17:44:28 +0000

Here’s how to determine the dates when the Daylight Savings Time changes for a given year (I keep forgetting how to do this.):



zdump -v /etc/localtime|grep 2008

/etc/localtime  Sun Mar  9 06:59:59 2008 UTC =
    Sun Mar 9 01:59:59 2008 EST isdst=0 gmtoff=-18000
/etc/localtime  Sun Mar  9 07:00:00 2008 UTC =
    Sun Mar 9 03:00:00 2008 EDT isdst=1 gmtoff=-14400
/etc/localtime  Sun Nov  2 05:59:59 2008 UTC =
    Sun Nov 2 01:59:59 2008 EDT isdst=1 gmtoff=-14400
/etc/localtime  Sun Nov  2 06:00:00 2008 UTC =
    Sun Nov 2 01:00:00 2008 EST isdst=0 gmtoff=-18000

Obviously, change 2008 to whatever year you want.

Bourne Shell Logging Routine

celso — Wed, 29 Aug 2007 03:20:19 +0000

Here’s another logging routine, this one is written in Bourne shell:

#!/bin/sh

log_message() {
    echo `date "+%m/%d/%y %H:%M:%S %Z"` "$1" | tee -a aaa.out
}

log_message "Hello there"
log_message "Goodbye"

Sample output:

08/28/07 23:16:13 EDT Hello there
08/28/07 23:16:13 EDT Goodbye

Determining the External IP Address

celso — Wed, 07 Jun 2006 17:33:15 +0000

Here’s how to find out your external IP address courtesy of this hint:

http://www.macosxhints.com/article.php?story=20060602180942480


curl --silent http://checkip.dyndns.org
    | awk '{print $6}' | cut -f 1 -d "<"

If you are using Apple's Airport Extreme Basestation (mine is particularly the Time Capsule and this is where I have tested this), and you have the SNMP interface enabled, you can run the following command


prompt$ snmpwalk -Os -c public -v 1 192.168.63.1 ipAdEntAddr IpAddress \
    | grep -E -v '(127.0.0|169.254|192.168.63.1)' \
    | cut -d : -f 2 | sed 's/ //g'

Line Terminations

celso — Thu, 13 Apr 2006 21:11:13 +0000

Line terminations for different operating systems:

unix	0x0a	LF
Classic Mac	0x0d	CR
Windows	0x0d 0x0a	CR LF

To convert a text file with DOS line termination to UNIX line termination:


tr -d '\015' < winfile.txt > unixfile.txt


sed s/.$// winfile.txt > unixfile.txt

To convert a unix file to a DOS file:


sed s/$/\x0d/ unixfile.txt > winfile.txt

Run Periodic Maintenance Scripts Manually

celso — Sun, 12 Feb 2006 02:58:33 +0000

Mac OS X has to run some maintenance scripts in the middle of the night to do some important housekeeping tasks. If you have a Mac that sleeps in the middle of the night, as you do, you need to run these manually by running this from the shell:


sudo periodic daily weekly monthly

Change Behavior of iTunes Arrows

celso — Sat, 11 Sep 2004 02:04:12 +0000

Starting with iTunes 4.5, Apple implemented those little grey arrows next to the song title, artist, and album, which will take you to the corresponding match in the iTunes Music Store. To change the behavior of these arrows so that instead of going to the store, it will take you to your library instead, you can do either one of two ways:

Hit option key when you click the arrow.
Change it permamnently by executing this from the terminal:
```
defaults write com.apple.iTunes invertStoreLinks -bool YES
```
Make sure iTunes is not running when you execute this command.

Enable Safari Debug Menu

celso — Wed, 08 Sep 2004 18:42:00 +0000

To enable Safari Debug menu from the command line:

% defaults write \
com.apple.Safari IncludeDebugMenu 1

Make sure Safari is not running when you run this command.