[FFmpeg-user] ffmpeg command line issue

[王知践]

hi,
I want to execute this command `ffmpeg -i $videoname -y -ar 16000 -ac 1 -f
s16le -acodec pcm_s16le $pcmaudioname` on my shell scripts. And if it
failed, i run command `ffmpeg -i $videoname -y -ar 8000 -ac 1 -f s16le
-acodec pcm_s16le $pcmaudioname`.
I don't known how to check command  `ffmpeg -i $videoname -y -ar 16000 -ac
1 -f s16le -acodec pcm_s16le $pcmaudioname` failed or success.

Thank you