How to get current foreground application's name or PID in OS X?

Question

I need to to get current foreground application's name or PID in OS X? How to get it using terminal?

Answer 1

You can find this information from the terminal using the 'lsappinfo' command. The man page has a lot of detail about the huge amount of information that this tool can return.

In order to get the frontmost application, you can call lsappinfo with the front argument.

$ lsappinfo front
ASN:0x0-0x10010:

This returns the unique application specifier (ASN) that launch services uses to identify processes. You can feed that back in to lsappinfo to get more details about that process.

$ lsappinfo info `lsappinfo front`
"Terminal" ASN:0x0-0x10010: (in front) 
    bundleID="com.apple.Terminal"
    bundle path="/Applications/Utilities/Terminal.app"
    executable path="/Applications/Utilities/Terminal.app/Contents/MacOS/Terminal"
    pid = 652 type="Foreground" flavor=3 Version="326" fileType="APPL" creator="????" Arch=x86_64 
    parentASN="loginwindow" ASN:0x0-0x1001: 
    launch time =  2014/06/25 15:13:00 ( 8 days, 39 minutes, 25.0882 seconds ago )
    checkin time = 2014/06/25 15:13:00 ( 8 days, 39 minutes, 24.6907 seconds ago )
    launch to checkin time: 0.397498 seconds

The info flag takes a -only flag to only return certain fields. Using that, you can query for the PID, the app name, the path to the app bundle, etc.

$ lsappinfo info -only pid `lsappinfo front` 
"pid"=652

$ lsappinfo info -only name `lsappinfo front` 
"LSDisplayName"="Terminal"

$ lsappinfo info -only bundlepath `lsappinfo front` 
"LSBundlePath"="/Applications/Utilities/Terminal.app"