File content to single JSON string value with bash

Question

I would like to read a file and put the whole content into a single string that is escaped to be used in a JSON object.

And I want to do it on the commandline/terminal (Linux).

Answer 1

Version 1

WARNING: With this solution the content of the file can be too big to fit in an argument!

jq  -n                                \
   --arg content "$(cat theFile.txt)" \
   '{ theContent : $content }'        \
|                                     \
jq '.theContent'

Version 2

Jeff Mercado provided a more compact solution for the first part - so I adapted that in my code as follows:

jq -Rs                  \
   '{ theContent: . }'  \
   theFile.txt          \
|                       \
jq '.theContent'

Version 3

Now Jeff Mercado provided a more compact solution for what I was looking for:

jq -Rs '.' theFile.txt

Answer 2

A more direct way to do that is to use the raw input (-R) combined with slurp (-s) parameters to read the entire input as a single string. Then take that input and store in the appropriate property. You don't need to pass it in as a separate parameter.

$ jq -Rs '{ theContent: . }' theFile.txt