'How to take string format from command line?

https://stedolan.github.io/jq/manual/#Stringinterpolation-%5C(foo)

I want to pass string format from the command line of jq, instead of embedding the format in string interpolation.

Let's say the format string is "my string %s". How to modify the following jq command to take the format string in its argument so that the output will be "my string x"?

jq --arg format "my string %s" -r -e . <<< '"x"'
jq


Solution 1:[1]

Put your (dynamic) jq expression inside \(…), which in turn is part of a (static) string expression "…". If all you want is passing on the input, use the identity function ., and your example should read

jq -r -e '"my string \(.)"' <<< '"x"'

my string x

Demo

Having "my string %s" as a parameter string, you cannot use it for string interpolation, as string interpolation is a language construct, and jq does not provide an eval (or similar) function to evaluate a variable's content as code.

What you can do instead is to (naively) replace %s with something else using sub or gsub:

jq -r -e -n --arg f "my string %s" '$f | sub("%s"; input)' <<< '"x"'

my string x

Demo

Sources

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Source: Stack Overflow

Solution Source
Solution 1

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