linux - How can I get the length of a video file from the console?

Suppose we have a video file some_video.

How can I get its length from a shell script (with mplayer/transcode/gstreamer/vlc/ffmpeg/whatever)?

VIDEO_LENGTH_IN_SECONDS=`ffmpeg .... -i some_video ... | grep -o .....`

Answer

ffprobe -i some_video -show_entries format=duration -v quiet -of csv="p=0"

will return the video duration in seconds.