Printing JSON in the Shell

Printing json might seem straightforward at first, just:

$ echo '{"name": "jes", "sign": "aquarius"}'
# {"name": "jes", "sign": "aquarius"}

but inevitably, variables show up:

$ echo '{"name": "$name", "sign": "$sign"}'
# {"name": "$name", "sign": "$sign"} <-- this output is very broken

We can instead use printf! printf offers several advantages over echo:

many languages (C, Go) have a printf equivalent, so it feels familiar
printf behavior does not differ across systems (it is posix compliant)
printf handles escape sequences (printf "hello\nworld\n")
printf can trivially handle json

Printing the same json text using printf:

$ printf '{"name": "%s", "sign": "%s"}' "$name" "$sign"
# {"name": "jes", "sign": "aquarius"}