How to use linux commands to convert and splice audio formats

eric@ray:~$ sudo apt install FFmpeg flac

eric@ray:~$ sudo apt install lame faac

eric@ray:~/Music$ ffmpeg -i Gracie-Theme.ape Gracie-Theme.wav

##or eric@ray:~/Music$ flac -d Gracie-Theme.flac Gracie-Theme.wav

##Use lame command: Use VBR dynamic bit rate compression, 0 means the highest quality, 9 means the lowest quality, the default is 4

eric@ray:~/Music$ lame -v Gracie-Theme.wav

##Or use faac encoding to get m4a (mp4) or mp3 format files: 100 means the highest quality is 100% 

eric@ray:~/Music$ faac -w -q 100 Gracie-Theme.wav -o Gracie-Theme.mp4

#Here we use the built-in aac encoding of ffmpeg, and set the bit rate to a fixed 320k

eric@ray:~/Music$ ffmpeg -i Gracie-Theme.wav -strict experimental -c:a aac -b:a 320k Gracie-Theme.m4a

#You can also use ffmpeg to decompress and compress in one command: -map_metadata means to keep the song metadata, i.e. name, singer, etc. eric@ray:~/Music$ ffmpeg -i Gracie-Theme.flac -ab 320k -map_metadata 0 Gracie-Theme.m4a

#!/bin/bash

for FILE in *.ape;
do
ffmpeg -i "$FILE" temp.wav;
lame -b 320 temp.wav "${FILE%.*}.mp3";
rm temp.wav
done

eric@ray:~/Music$mp3splt -c song.cue -o @n.@t song.mp3

# Audio merging (two audios overlap)

eric@ray:~/Music$ffmpeg -i first.mp3 -i second.mp3 -filter_complex amix=inputs=2:duration=first:dropout_transition=2 -f mp3 third.mp3

#Two audio splicing eric@ray:~/Music$ffmpeg -i d1.mp3 -i d2.mp3 -filter_complex '[0:0] [1:0] concat=n=2:v=0:a=1 [a]' -map [a] j5.mp3

#Three audio splicing eric@ray:~/Music$ffmpeg -i title.wav -i content.WAV -i end.wav -filter_complex '[0:0] [1:0] [2:0] concat=n=3:v=0:a=1 [a]' -map [a] synthesis.wav