Video & Screenshot

Screenshot:

use scrot -s
 

Video screen record:
 * simplescreenrecorder

Trim / Compress video:

ffmpeg 

trim video: ffmpeg -i film.mkv  -to 01:46:58 -c:v copy -c:a copy output.mp4
compress video: ffmpeg -i input.mp4 -vcodec libx265 -crf 28 output.m