using jq to assign multiple output variables - bash

Question

I am trying to use jq to parse information from the TVDB api. I need to pull a couple of fields and assign the values to variables that I can continue to use in my bash script. I know I can easily assign the output to one variable through bash with variable="$(command)" but I need the output to produce multiple variables and I don't want to make to use multiple commands.
I read this documentation:
https://stedolan.github.io/jq/manual/v1.5/#Advancedfeatures
but I don't know if this relevant to what I am trying to do.
jq '.data' produces the following output:
[
{
"absoluteNumber": 51,
"airedEpisodeNumber": 6,
"airedSeason": 4,
"airedSeasonID": 680431,
"dvdEpisodeNumber": 6,
"dvdSeason": 4,
"episodeName": "We Will Rise",
"firstAired": "2017-03-15",
"id": 5939660,
"language": {
"episodeName": "en",
"overview": "en"
},
"lastUpdated": 1490769062,
"overview": "Clarke and Roan must work together in hostile territory in order to deliver an invaluable asset to Abby and her team."
}
]
I tried jq '.data | {episodeName:$name}' and jq '.data | .episodeName as $name' just to try and get one working. I don't understand the documentation or even if it's what I'm looking for. Is there a way to do what I am trying to do?

Answer 1

You can use separate variables with read :
read var1 var2 var3 < <(echo $(curl -s 'https://api.github.com/repos/torvalds/linux' |
jq -r '.id, .name, .full_name'))
echo "id : $var1"
echo "name : $var2"
echo "full_name : $var3"
Using array :
read -a arr < <(echo $(curl -s 'https://api.github.com/repos/torvalds/linux' |
jq -r '.id, .name, .full_name'))
echo "id : ${arr[0]}"
echo "name : ${arr[1]}"
echo "full_name : ${arr[2]}"
Also you can split jq output with some character :
IFS='|' read var1 var2 var3 var4 < <(curl '......' | jq -r '.data |
map([.absoluteNumber, .airedEpisodeNumber, .episodeName, .overview] |
join("|")) | join("\n")')
Or use an array like :
set -f; IFS='|' data=($(curl '......' | jq -r '.data |
map([.absoluteNumber, .airedEpisodeNumber, .episodeName, .overview] |
join("|")) | join("\n")')); set +f
absoluteNumber, airedEpisodeNumber, episodeName & overview are respectively ${data[0]}, ${data[1]}, ${data[2]}, ${data[3]}. set -f and set +f are used to respectively disable & enable globbing.
For the jq part, all your required fields are mapped and delimited with a '|' character with join("|")
If your are using jq < 1.5, you'll have to convert Number to String with tostring for each Number fields eg:
IFS='|' read var1 var2 var3 var4 < <(curl '......' | jq -r '.data |
map([.absoluteNumber|tostring, .airedEpisodeNumber|tostring, .episodeName, .overview] |
join("|")) | join("\n")')

Answer 2

jq always produces a stream of zero or more values. For example, to produce the two values corresponding to "episodeName" and "id"' you could write:
.data[] | ( .episodeName, .id )
For your purposes, it might be helpful to use the -c command-line option, to ensure each JSON output value is presented on a single line. You might also want to use the -r command-line option, which removes the outermost quotation marks from each output value that is a JSON string.
For further variations, please see the jq FAQ https://github.com/stedolan/jq/wiki/FAQ, e.g. the question:
Q: How can a stream of JSON texts produced by jq be converted into a bash array of corresponding values?

Answer 3

Experimental conversion of quoted OP input, (tv.dat), to a series of bash variables, (and an array). The jq code is mostly borrowed from here and there, but I don't know how to get jq to unroll an array within an array, so the sed code does that, (that's only good for one level, but so are bash arrays):
jq -r ".[] | to_entries | map(\"DAT_\(.key) \(.value|tostring)\") | .[]" tv.dat |
while read a b ; do echo "${a,,}='$b'" ; done |
sed -e '/{.*}/s/"\([^"]*\)":/[\1]=/g;y/{},/() /' -e "s/='(/=(/;s/)'$/)/"
Output:
dat_absolutenumber='51'
dat_airedepisodenumber='6'
dat_airedseason='4'
dat_airedseasonid='680431'
dat_dvdepisodenumber='6'
dat_dvdseason='4'
dat_episodename='We Will Rise'
dat_firstaired='2017-03-15'
dat_id='5939660'
dat_language=([episodeName]="en" [overview]="en")
dat_lastupdated='1490769062'
dat_overview='Clarke and Roan must work together in hostile territory in order to deliver an invaluable asset to Abby and her team.'