magick-import
Capture some or all of an X server screen and save the image to a file. tldr-pages
On several platforms
Several platforms
Capture the entire X server screen into a PostScript file
magick import -window root path/to/output.psIdentifyCapture contents of a remote X server screen into a PNG image
magick import -window root -display remote_host:screen.display path/to/output.pngIdentifyCapture a specific window given its ID as displayed by xwininfo into a JPEG image
magick import -window window_id path/to/output.jpgIdentify