Verifying if a string or file is valid json is easy with jq.
Check if a string is valid json
Using the -e argument, jq will return a 0 if the last output was neither false nor null.
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| if jq -e . >/dev/null 2>&1 <<<'{"test": "value"}'; then
echo "parsed successfully"
else
echo "could not parse json string"
fi
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In addition, negating the above condition may increase readability:
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| if ! jq -e . >/dev/null 2>&1 <<<'{"test": "value"}'; then
echo "could not parse json string"
exit 1
fi
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Using a variable:
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| if ! jq -e . >/dev/null 2>&1 <<<"$json"; then
echo "could not parse json string"
exit 1
fi
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Check if a file is valid json
Using the same technique from above:
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| if ! jq -e . >/dev/null 2>&1 <<<$(cat invalid.json); then
echo "could not parse json file"
exit 1
fi
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the invalid.json file:
will output:
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| could not parse json file
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