jq json path single quotes and variable

Question

Trying to figure out the syntax for jq. This line works absolutely fine:

echo $(cat ../post-auth/rkt-auth.json | jq -c --arg user ${vsphere_user} '.credentials.user = $user') > ../post-auth/rkt-auth.json

However this is not the case when variable is a part of json path:

echo $(cat ../post-auth/docker-auth.json | jq -c --arg basejq ${base} --arg tempvarjq ${tempvar} '.auths.$tempvarjq.auth= $basejq') > ../post-auth/docker-auth.json

Error:

jq: error: syntax error, unexpected '$', expecting FORMAT or QQSTRING_START (Unix shell quoting issues?) at <top-level>, line 1:
.auths.$tempvarjq.auth= $basejq       
jq: 1 compile error

Any suggestions how to correct this syntax with that variable?

That's a [useless use of `echo`](http://www.iki.fi/era/unix/award.html#echo) and a [useless `cat`](/questions/11710552/useless-use-of-cat) btw. — tripleee, Jan 14 '19 at 15:54
Also, if your input file is the same as your output file, this is [bound to cause some issues](https://stackoverflow.com/questions/36565295/jq-to-replace-text-directly-on-file-like-sed-i) — Aserre, Jan 14 '19 at 15:58
`echo "$(cat file)" >file` isn't guaranteed to do all the reading before it does any writing. Many shells *will* run the command substitution before they run the redirection, but it's not a firm guarantee by the letter of the POSIX standard, and shouldn't be relied on. (Also, even if your shell *does* honor that order-of-operations, it means a failed `cat` run will still invoke `echo`, so your file will be blanked rather than left alone in the event of an error). — Charles Duffy, Jan 14 '19 at 16:26

score 2 · Answer 1 · edited Jan 14 '19 at 16:08

2

Try this.

jq -c --arg basejq "${base}" \
    --arg tempvarjq "${tempvar}" \
    '.auths[$tempvarjq].auth= $basejq' \
    ../post-auth/docker-auth.json \
        > ../post-auth/docker-auth.json.tmp &&
mv  ../post-auth/docker-auth.json.tmp  \
    ../post-auth/docker-auth.json

edited Jan 14 '19 at 16:08

peak

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answered Jan 14 '19 at 16:00

tripleee

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Not in a place where I can test - I'll simply delete this if it doesn't work. – tripleee Jan 14 '19 at 16:00
it worked thanks, and sorry if this was a dup, I couldn't piece it together from other posts, make sense now – Chris Jan 17 '19 at 16:23

jq json path single quotes and variable

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