I have written a script to retrieve certain value from file.json
. It works if I provide the value to jq select
, but the variable doesn't seem to work (or I don't know how to use it).
#!/bin/sh
#this works ***
projectID=$(cat file.json | jq -r '.resource[] | select(.username=="[email protected]") | .id')
echo "$projectID"
[email protected]
#this does not work *** no value is printed
projectID=$(cat file.json | jq -r '.resource[] | select(.username=="$EMAILID") | .id')
echo "$projectID"
This question is related to
json
bash
environment-variables
jq
It's a quote issue, you need :
projectID=$(
cat file.json | jq -r ".resource[] | select(.username=='$EMAILID') | .id"
)
If you put single quotes to delimit the main string, the shell takes $EMAILID
literally.
"Double quote" every literal that contains spaces/metacharacters and every expansion: "$var"
, "$(command "$var")"
, "${array[@]}"
, "a & b"
. Use 'single quotes'
for code or literal $'s: 'Costs $5 US'
, ssh host 'echo "$HOSTNAME"'
. See
http://mywiki.wooledge.org/Quotes
http://mywiki.wooledge.org/Arguments
http://wiki.bash-hackers.org/syntax/words
Posting it here as it might help others. In string it might be necessary to pass the quotes to jq. To do the following with jq:
.items[] | select(.name=="string")
in bash you could do
EMAILID=$1
projectID=$(cat file.json | jq -r '.resource[] | select(.username=='\"$EMAILID\"') | .id')
essentially escaping the quotes and passing it on to jq
I know is a bit later to reply, sorry. But that works for me.
export K8S_public_load_balancer_url="$(kubectl get services -n ${TENANT}-production -o wide | grep "ingress-nginx-internal$" | awk '{print $4}')"
And now I am able to fetch and pass the content of the variable to jq
export TF_VAR_public_load_balancer_url="$(aws elbv2 describe-load-balancers --region eu-west-1 | jq -r '.LoadBalancers[] | select (.DNSName == "'$K8S_public_load_balancer_url'") | .LoadBalancerArn')"
In my case I needed to use double quote and quote to access the variable value.
Cheers.
I resolved this issue by escaping the inner double quotes
projectID=$(cat file.json | jq -r ".resource[] | select(.username==\"$EMAILID\") | .id")
Another way to accomplish this is with the jq "--arg" flag. Using the original example:
#!/bin/sh
#this works ***
projectID=$(cat file.json | jq -r '.resource[] |
select(.username=="[email protected]") | .id')
echo "$projectID"
[email protected]
# Use --arg to pass the variable to jq. This should work:
projectID=$(cat file.json | jq --arg EMAILID $EMAILID -r '.resource[]
| select(.username=="$EMAILID") | .id')
echo "$projectID"
See here, which is where I found this solution: https://github.com/stedolan/jq/issues/626
Jq now have better way to acces environment variables, you can use env.EMAILI:
projectID=$(cat file.json | jq -r ".resource[] | select(.username==env.EMAILID) | .id")
Little unrelated but I will still put it here, For other practical purposes shell variables can be used as -
value=10
jq '."key" = "'"$value"'"' file.json
Source: Stackoverflow.com