string variable interpolation

Question

I've coded this script:

for i in `seq 1 $1`; do
        timestamp=$(uuidgen)
        cat $2.json | jq '.transactionId = "$timestamp"' > $3/$timestamp.json
done

My issue is on jq '.transactionId = "$timestamp"' since the content of file is:

{
  "transactionId": "$timestamp"
}

Any ideas?

You mentioned you have an issue with a particular line. Could you tell us what the issue is and why it is an issue? — kvantour, Jan 08 '19 at 13:46
Just change single quotes for double quotes: `jq "... '$timestamp'"` — F. Hauri, Jan 08 '19 at 13:54
As an aide, avoid the [useless `cat`](/questions/11710552/useless-use-of-cat) and [quote all your variables.](/questions/10067266/when-to-wrap-quotes-around-a-shell-variable) — tripleee, Jan 09 '19 at 05:09

score 6 · Answer 1 · edited Jan 08 '19 at 14:10

6

There are better ways to pass variables to jq:

$ cat data.test
{
  "foo": "noooo"
}
$ new=bar
$ jq --arg new_foo "$new" '.foo |= $new_foo' data.test
{
  "foo": "bar"
}

edited Jan 08 '19 at 14:10

Aserre

answered Jan 08 '19 at 13:50

mickp

in this case, wouldn't `=` be enough rather than `|=` ? – Aserre Jan 08 '19 at 14:11

1 Answers1