This can be done by using the "New Text Document Here" action
Select folder -> tab -> start typing "New" -> select "New Text Document Here" -> type name -> enter.
If you're looking for a more complete solution that can create any type of file (including ones without the .txt extension that the New Text Document action forces) try this Applescript. Just put it in a file named
New File.applescript in the
~/Library/Application Support/LaunchBar/Actions/ directory:
display dialog "Enter filename:" default answer ""
set fname to text returned of result
set fullpath to dir & fname
do shell script "touch '" & fullpath & "'"
open location "x-launchbar:select?file=" & fullpath
on error errMsg
display dialog "Error: " & errMsg
open location "x-launchbar:hide"
It'll touch the file, then select it in LaunchBar upon completion (you can comment out the line that does that by adding
-- to the beginning of the line or just removing it).