You might be better served with gnu parallel - #create the directory structure first find . -type f -name '*.flac' |ionice -c3 parallel -j1 'mkdir -p $tran

You might be better served with gnu parallel - #create the directory structure first find . -type f -name '*.flac' |ionice -c3 parallel -j1 'mkdir -p $transcodes{//}' && #now the encodes find . -type f -name '*.flac' |ionice -c3 parallel -j4 "ffmpeg -n -v 0 -i {} -c:a libopus -b:a 128k $transcodes{.}.opus" Note the {.} which would actually only grab the basename.