A large number of music files, generate the total a json file, but build library or have a problem.

[holens]

Does the following step:
1. find ./ -regex '..m4a|..mp3' > music_to_ingest
2. echoprint-codegen -s < music_to_ingest > allcodes.json
3. cat allcodes.json | jq -r '.[].code' | echoprint-inverted-index index.bin

My system is 4 gb of memory,2 gb swap space. when I run the step of 3, At the last time Out of memory and swap space. but the file size of allcodes.json is 1gb.
What reason is this ?