Assign string with spaces to variable and escape those spaces-CodePudding

I'm trying to get some json data using jq:

{
    "meta": {
        "title": "This is a title",
        "description": "Just a description"
    }
}

by running jq -r '.meta | .title, .description' ./project.json, which gives me the expected result:

This is a title
Just a description

Now I need to assign the content to a variable in my bash script:

read TITLE DESCRIPTION < <(echo $(jq -r '.meta | .title, .description' ./project.json))

But this is not working because of the spaces. Also later I have to escape all spaces, which I would do with:

echo ${TITLE// /\\ }

How should I handle the assignment of the variable (handling space content) and escape the spaces (maybe in one step)?

CodePudding user response：

No, you don't need to escape anything here.

Using NULs to delimit all values, so we can correctly support titles or descriptions that contain newlines:

{
  IFS= read -r -d '' title
  IFS= read -r -d '' description
} < <(jq -r '.meta | (.title, .description) | (., "\u0000")' )

If we assume that title and description cannot contain literal newlines, either of the below will do:

{
  IFS= read -r title
  IFS= read -r description
} < <(jq -r '.meta | .title, .description' ./project.json)

...or, telling read to look for a terminating NUL, and thereby ensuring that it has a nonzero exit status should jq fail (but still using a newline to separate the two values):

IFS=$'\n' read -r -d '' title description < <(
  jq -r '.meta | (.title, .description, "\u0000")' ./project.json
)

Taking advantage of jq's support for generating sh-compatible eval-safe escaping, we can also do the following, which does correctly handle strings with newlines:

eval "$(jq -r '
  .meta | "description=\(.description|@sh); title=\(.title|@sh)"
' ./project.json)"

CodePudding user response：

With builtin mapfile, bash and an array (title):

mapfile -t title < <(jq -r '.meta | .title, .description' project.json)
echo "${title[0]}"
echo "${title[1]}"

Output:

This is a title
Just a description

CodePudding user response：

Using some parameter substitutions:

$ x=$(jq ... )
$ title="${x%$'\n'*}"
$ description="${x#*$'\n'}"
$ typeset -p title description
declare -- title="This is a title"
declare -- description="Just a description"