Changing the default screenshot filename Is there a way to change the default screenshot filename prefix (the Cmd-Shift-4 type screenshot) to something other than the default? The default name looks like this:

Screen Shot 2011-08-30 at 10.01.36 AM.png


But I'd prefer to use something like:

screenshot_2011-08-30_100136.png


Basically so I can remove the spaces and junk, since it's annoying to browse dig through files in Terminal. Any easy way to change this prefix with one of the defaults write com.apple.screencapture style commands?
You can change 'Screen shot' to 'screenshot' with the following commands  

defaults write com.apple.screencapture name screenshot
killall SystemUIServer  

If you want to go digging a bit deeper in Terminal, you can achieve what you want by doing the following:  

NOTE: Make a backup of any files you change in case you make a mistake.  


cd /System/Library/CoreServices/SystemUIServer.app/Contents/Resources/English.lproj
Make a copy of the existing file:
sudo cp ScreenCapture.strings ScreenCapture.strings.old
Enter Admin password if prompted
Convert to an editable format:
sudo plutil -convert xml1 ScreenCapture.strings
sudo vi ScreenCapture.strings  

Locate the following lines:  

&lt;key&gt;%@ %@ at %@&lt;/key&gt;  
&lt;string&gt;%@ %@ at %@&lt;/string&gt;  


and replace with the following lines:  

&lt;key&gt;%@ %@ at %@&lt;/key&gt;  
&lt;string&gt;%@_%@_%@&lt;/string&gt;  

Convert back to binary:
sudo plutil -convert binary1 ScreenCapture.strings
killall SystemUIServer


which combined with the first change should get you something like this:  

screenshot_2011-08-30_10.01.36.png which is very close to what you need I think