From: ldo@nz.invalid   
      
   On Thu, 13 Feb 2025 22:52:44 -0000 (UTC), I wrote:   
      
   > What’s the most complex *nix command you’ve come across? I think it has   
   > to be ffmpeg.   
      
   For example, here’s a command I came up with for using ffmpeg to   
   convert an audio file for playback through the Asterisk telephony   
   engine. The sample rate has to be 8kHz, so to make sure there are no   
   aliasing artifacts, you have to make sure there are no frequency   
   components above about 3kHz. To achieve this, I apply a first-order   
   low-pass filter 16 times in a row, to produce a “brick wall” cutoff at   
   that frequency:   
      
   ffmpeg -i in.wav -f s16le -acodec pcm_s16le -ar 8000 \   
       -af $(sep=""; for i in $(seq 16); do echo -n ${sep}lowpass=f=3000;   
   sep=","; done) \   
       out.slin   
      
   Note the substitution of the output of one command inside another, not   
   just to one, but two levels of nesting.   
      
   --- SoupGate-DOS v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)