Handy OS X Terminal Commands

Set Time Machine’s Backup Interval

Time Machine will attempt to backup once per hour.  As with many things in OS X, a preference to change the time between backups exists, but Apple doesn’t make such options available in the preference panel.  Terminal to the rescue.  Command below takes number of seconds, so one week between backups is 7*24*60*60 = 604800.  I had to restart to get the change to register.

sudo defaults write /System/Library/LaunchDaemons/com.apple.backupd-auto StartInterval -int 604800

Disable Safe Sleep on OS X

When putting a mac to sleep, typically it writes the contents of the RAM to the hard disk so that if power is totally lost, the machine state is still saved and recoverable later.  However, this results in extra hard drive activity for up to 20 seconds after closing the lid on my Macbook.  When using my laptop, I want to be very careful not to move the computer around while the hard drive is active, in case I damage the drive by sudden movements.  So I want my computer to go asleep and shut the drives down right away, so I can get up and move the computer safely!

sudo pmset -a hibernatemode 0
sudo nvram "use-nvramrc?"=false

Disable “Are you sure you want to open it?” Prompt

Starting in Mac OS X 10.5, you will get this prompt the first time you open a file downloaded from the internet or web.  I have received this prompt with disk images, zip files, but even fairly “safe” things like plain text files and HTML source code.  Anyway, I know what I’m downloading, and I know what I am doing, thank you very much.  I will disable the prompt now.

defaults write com.apple.LaunchServices LSQuarantine -bool NO