for i in *.asf; do ffmpeg -i $i -bsf:v h264_mp4toannexb -c:v copy $i.mp4; done
ffmpeg -ss 00:00:00 -i NVR_ch1_main_20180712001236_20180712005603.dav.mp4 -t 00:21:00 -vcodec copy -acodec copy newfile.mp4
mysqldump -u root -p violet --ignore-table=violet.challan --where='1 limit 100'> all.sql