Passing bash variable to jq

Question

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   myemail hotmail com      id   echo   projectID   EMAILID myemail hotmail com   this does not work     no value is printed projectID   cat file json   jq -r   resource     select  username    EMAILID      id   echo   projectID

User · Answer

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

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I resolved this issue by escaping the inner double quotes  projectID   cat file json   jq -r   resource     select  username     EMAILID       id

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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  amp  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

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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

User · Answer

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

User · Answer

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   myemail hotmail com      id   echo   projectID   EMAILID myemail hotmail com    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

User · Answer

Consider also passing in the shell variable  EMAILID  as a jq variable  here also EMAILID  for the sake of illustration      projectID   jq -r --arg EMAILID  quot  EMAILID quot             resource             select  username   EMAILID              id  file json   Postscript For the record  another possibility would be to use jq s env function for accessing environment variables   For example  consider this sequence of bash commands  EMAILID foo bar com    not exported EMAILID  quot  EMAILID quot  jq -n  env EMAILID   The output is a JSON string   quot foo bar com quot

User · Answer

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

[json] Passing bash variable to jq

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