Random Tech Thoughts

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Disabling Spotlight indexing while indexing is in progress

From Spotlight tips

sudo mdutil -i off /path_to_volume

Disabling spotlight on some volume

Create an empty file with name .metadata_never_index in the volume’s root folder.

It’s better to also put an empty file named no_log in .fsevent.

Command line settings

The following several settings are from Top 15 Terminal Commands for Hidden Settings in Snow Leopard and Terminal Commands for Hidden Settings in Leopard

Reset “Open With” menu

  /System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/LaunchServices.framework/Versions/A/Support/lsregister \
      -kill -r -domain local -domain system -domain user

The open with preference is stored in ~/Library/Preferences/com.apple.LaunchServices.plist. If resetting does not work, try first delete that file.

Show hidden files in the Finder

  defaults write com.apple.finder AppleShowAllFiles -bool YES

Show full path in Finder’s title

  defaults write com.apple.finder _FXShowPosixPathInTitle -bool YES

Disable crash reporter dialog

This does not disable crash logging

  defaults write com.apple.CrashReporter DialogType none

Other command line settings

From this gist. The following are what I used.

echo "Enable iTunes track notifications in the Dock"
defaults write com.apple.dock itunes-notifications -bool true

echo "Disable the “Are you sure you want to open this application?” dialog"
defaults write com.apple.LaunchServices LSQuarantine -bool false

echo "Avoid creating .DS_Store files on network volumes"
defaults write com.apple.desktopservices DSDontWriteNetworkStores -bool true

echo "Disable the warning before emptying the Trash"
defaults write com.apple.finder WarnOnEmptyTrash -bool false

echo "Make Safari’s search banners default to Contains instead of Starts With"
defaults write com.apple.Safari FindOnPageMatchesWordStartsOnly -bool false

echo "Disable Safari’s thumbnail cache for History and Top Sites"
# To re-enable, invoke the command without "-int 2"
defaults write com.apple.Safari DebugSnapshotsUpdatePolicy -int 2

echo "Disable dashboard"
defaults write com.apple.dashboard mcx-disabled -boolean true

Change Calendar/Fanstical default event duration

echo "Change Calendar default event duration"
defaults write com.apple.iCal 'Default duration in minutes for new event' 15

echo "Change Fantastical default event duration time"
defaults write com.flexibits.fantastical 'Default duration in minutes for new event' 0

Use 64 bit kernel

Note, Lion uses 64 bit kernel by default.

During startup, press and hold “6” and “4” keys. To use 64 bit as default kernel, use:

sudo systemsetup -setkernelbootarchitecture x86_64

Press “3” and “2” or change x86_64 to i386 for 32 bit kernel.

Time Machine related

Disable local Time Machine

Local Time Machine backup takes up too much disk space. Use the following command to disable it:

sudo tmutil disablelocal

Manually delete backups

From apple.stackexchange

sudo tmutil delete /Volumes/drive_name/Backups.backupdb/mac_name/YYYY-MM-DD-hhmmss

VNC client shipped in OS X

It’s located at /System/Library/CoreServices/Screen Sharing.app

Disable hibernate

I replaced the optical driver with an SSD disk. Hibernate will create a memory image file /var/vm/sleepimage to ensure recover state after running out of battery. This is rare case for me so I disable it. This can also speed up sleeping since no data need to be written to disk.

$ sudo pmset -a hibernatemode 0
$ sudo rm /var/vm/sleepimage

More info on OS X Daily. If hibernate is not disabled, after deletion of the sleep image, it will be recreated the next time you put Mac into sleep.

Enable TRIM for SSD

From Grant Pannell, or look at this gist.

  1. Backup

    cd /System/Library/Extensions/IOAHCIFamily.kext/Contents/PlugIns/IOAHCIBlockStorage.kext/Contents/MacOS/
    sudo cp IOAHCIBlockStorage IOAHCIBlockStorage.bak
  2. Patch the driver

    FOR ML 10.8.3
    sudo perl -pi -e 's|(\x52\x6F\x74\x61\x74\x69\x6F\x6E\x61\x6C\x00{1,20})[^\x00]{9}(\x00{1,20}\x54)|$1\x00\x00\x00\x00\x00\x00\x00\x00\x00$2|sg' /System/Library/Extensions/IOAHCIFamily.kext/Contents/PlugIns/IOAHCIBlockStorage.kext/Contents/MacOS/IOAHCIBlockStorage
    FOR ML 10.8.1-10.8.2 AND LION 10.7.5
    sudo perl -pi -e 's|(\x52\x6F\x74\x61\x74\x69\x6F\x6E\x61\x6C\x00{1,20})[^\x00]{9}(\x00{1,20}\x4D)|$1\x00\x00\x00\x00\x00\x00\x00\x00\x00$2|sg' /System/Library/Extensions/IOAHCIFamily.kext/Contents/PlugIns/IOAHCIBlockStorage.kext/Contents/MacOS/IOAHCIBlockStorage
    FOR ML 10.8.0 AND LION 10.7.4 BELOW
    sudo perl -pi -e 's|(\x52\x6F\x74\x61\x74\x69\x6F\x6E\x61\x6C\x00{1,20})[^\x00]{9}(\x00{1,20}\x51)|$1\x00\x00\x00\x00\x00\x00\x00\x00\x00$2|sg' /System/Library/Extensions/IOAHCIFamily.kext/Contents/PlugIns/IOAHCIBlockStorage.kext/Contents/MacOS/IOAHCIBlockStorage
  3. Force a refresh of the system’s kernel extension cache

    sudo touch /System/Library/Extensions/
  4. Reboot

VMware Fusion 4 network setting

My wireless route uses as the network address range, this conflicts with the NAT address used by VMware Fusion. So I want to change the address used by VMware.

From the document VMware Fusion network setting

What does the 2 virtual network cards do?

  • vmnet1: host only network
  • vmnet8: NAT network

The following instructions to change NAT address range are learnt from Thomas Vachon

  1. The configuration is located at /Library/Preferences/VMware Fusion/networking. What need to be changed should be obvious
  2. Files that will be automatically updated after staring VMware Fusion
    • networking
    • vmnet8/{dhcpd.conf,nat.conf} Note locations will not be updated, but I have no problem even if I don’t update it.

Kernel module utilities

From Mac OS X for Unix Geeks

  • kextload
  • kextunload
  • kextstat: display status of loaded kernel extensions

Dynamic library related

Look for which dynamic library is needed for a binary:

  otool -L foo

From man dyld, by export DYLD_PRINT_LIBRARIES=anyvalue, dyld will print out all the libraries a program is using.

Disable hold key to enter unicode character

defaults write -g ApplePressAndHoldEnabled -bool false

Font smoothing settings

Found on Mac OS X Hints.

Some LCD monitors are detected as CRT and LCD font smoothing is thus disabled.

Prior to Snow Leopard, the font smoothinging options were:

  • Automatic – Best for Main Display
  • Standard – Best for CRT
  • Light
  • Medium – Best for Flat Panel
  • Strong

In SL, we can only choose Automatic and Standard. To force OS X use LCD font smoothing on all display, use the following command:

defaults -currentHost write -globalDomain AppleFontSmoothing -int 2

The int value can beep – 1, Light – 2, Medium – 3, Strong

Converting DMG to ISO

Use hdiutil:

hdiutil convert original.dmg -format UDTO -o newisoimage.cdr

OS X insist on naming the ISO file with cdr extension.

Python: pip install to specified directory

From stackoverflow

pip install --install-option="--prefix=/usr/local" package_name

Adding local dev top level domain

Refer to serverfault.

First create a resolver for dev domain (man 5 resolver for more info).

# mkdir /etc/resolver
# echo 'nameserver' > /etc/resolver/dev

So domains under dev will use name server on So we need to setup a DNS server on local machine. I personally use dnsmasq. Just add the following in dnsmasq’s config:


So domains under dev will resolve to

In order to resolve when no network interface is active, create a file /etc/resolver/whatever

domain .

The name whatever is used to make it the last match with possible actual domain names.

LaunchDaemons vs. LanuchAgents

From Mac OS X: launch daemons vs launch agents.


  • can run without a user logged in
  • can’t display information using GUI
  • configuration stored in
    • /System/Library/LaunchDaemons (provided by apple)
    • /Library/LaunchDaemons (for the rest)


  • user need to be logged in to run
  • can use GUI
  • configuration stored in
    • /System/Library/LaunchAgents
    • /Library/LaunchAgents
    • ~/Library/LaunchAgents

Clean DSN cache

OS X 10.7 & 10.8

sudo killall -HUP mDNSResponder

OS X 10.6

dscacheutil -flushcache