I've seen in many pages here on SO (for example here: https://apple.stackexchange.com/questions/56561/how-do-i-find-the-windowid-to-pass-to-screencapture-l) that you have to use the command:
screencapture -l in order to capture a single window given its ID.
However when I try to enter screencapture -l into the terminal I get this error:
screencapture: illegal option -- l
I've checked a reference and actually I can't see -l as a possible attribute for screencapture: http://guides.macrumors.com/screencapture
How do you explain this? How can I solve this?
Not certain if this is a programming question or something better suited for apple.stackexchange.com, but anyways:
When I run "screencapture -l", I see this:
screencapture: illegal option -- l
usage: screencapture [-icMPmwsWxSCUtoa] [files]
-c force screen capture to go to the clipboard
-C capture the cursor as well as the screen. only in non-interactive modes
-d display errors to the user graphically
-i capture screen interactively, by selection or window
control key - causes screen shot to go to clipboard
space key - toggle between mouse selection and
window selection modes
escape key - cancels interactive screen shot
-m only capture the main monitor, undefined if -i is set
-M screen capture output will go to a new Mail message
-o in window capture mode, do not capture the shadow of the window
-P screen capture output will open in Preview
-s only allow mouse selection mode
-S in window capture mode, capture the screen not the window
-t<format> image format to create, default is png (other options include pdf, jpg, tiff and other formats)
-T<seconds> Take the picture after a delay of <seconds>, default is 5
-w only allow window selection mode
-W start interaction in window selection mode
-x do not play sounds
-a do not include windows attached to selected windows
-r do not add dpi meta data to image
-l<windowid> capture this windowsid
-R<x,y,w,h> capture screen rect
files where to save the screen capture, 1 file per screen
They don't make it clear in the above output ("windowsid"?), but it looks like the "-l" option requires a window id, so that screencapture would capture a single window on the screen.
