Create JSON of environment variables name-value pairs from array of environment variable names with jq in bash script

Question

Requirement:

In a BASH script,

...iterate over an array of environment variable names as shown below:

arr = ('env_var1' 'env_var2' 'env_var3')

and, using jq generate a JSON of environment variable name-value pairs like below:

{
 "env_var1": "env_var1_value_is_1",
 "env_var2": "env_var2_value_is_2",
 "env_var3": "env_var3_value_is_3"
}

Current approach: Using this stackoverflow question's solution as a reference

printf '%s\n' "${arr[@]}" |
  xargs -L 1 -I {} jq -sR --arg key {} '{ ($key): . }' | jq -s 'add'

where arr array contains the environment variable names for which I want the values, however I am unable to interpolate the ${environment_variable_name} into the JSON's value in each key-value pair

If not limited to jq, jo is a pretty cool tool, to construct JSON on the fly when the input is from an external source e.g. a bash array in this case — Inian
– Inian, Commented Nov 24, 2022 at 7:36

hobbs · Accepted Answer · 2022-11-24 07:35:05Z

3

How about

jq -n '$ARGS.positional | map({ (.): env[.] }) | add' --args "${arr[@]}"

Using $ARGS.positional with --args avoids the need to execute jq once per item in the array, and the env builtin is the thing you needed to pull values out of the environment.

answered Nov 24, 2022 at 7:35

hobbs

245k20 gold badges225 silver badges304 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Somnath Pathak Over a year ago

Thank you @hobbs! I believe you could guide me on the below as well. I input an object to my bash script which looks like {"env_var1": "env_var_expected_val_1", "env_var2": "env_var_expected_val_2"} and fetch all the keys (read: environment variable names) in an array i.e. arr with jq -r 'keys[]' which is inputed as the ${arr[@]} to the above given command. Is there a way I could use the jq pipe to combine all into one command?

peak · Accepted Answer · 2022-11-24 09:09:13Z

2

Since by assumption the variables referenced in arr are environment variables, you could use printf along the lines of your attempt as follows:

printf '%s\n' "${arr[@]}" | jq -nR '[inputs | {(.): env[.] }] | add'

This also works with gojq and fq, and might be useful if your jq does not support $ARGS

edited Nov 24, 2022 at 9:09

answered Nov 24, 2022 at 9:02

peak

119k21 gold badges185 silver badges218 bronze badges

Collectives™ on Stack Overflow

Create JSON of environment variables name-value pairs from array of environment variable names with jq in bash script

2 Answers 2

1 Comment

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related