cat /home/pt/sbd0.mp4 /home/pt/sbd1.mp4 > /home/pt/sbd01.mp4
the command can work,
sbd0.mp4 is 5' 14 '' , 15.6 M;sbd0.mp4 is 5' 14 '' , 15.6 M too
when i cat them , sbd01.mp4 is 31.2M
but i open sbd01 , i can see only 5' 14 '' movie,not 10'28''
why??