Query:
Is there a (Unix) shell script to format JSON in human-readable form?
Basically, I want it to transform the following:
{ "foo": "lorem", "bar": "ipsum" }
… into something like this:
{
"foo": "lorem",
"bar": "ipsum"
}
How to pretty-print JSON in a shell script?
With Python 2.6+ you can do:
echo '{"foo": "lorem", "bar": "ipsum"}' | python -m json.tool
or, if the JSON is in a file, you can do:
python -m json.tool my_json.json
if the JSON is from an internet source such as an API, you can use
curl http://my_url/ | python -m json.tool
For convenience in all of these cases you can make an alias:
alias prettyjson='python -m json.tool'
For even more convenience with a bit more typing to get it ready:
prettyjson_s() {
echo "$1" | python -m json.tool
}
prettyjson_f() {
python -m json.tool "$1"
}
prettyjson_w() {
curl "$1" | python -m json.tool
}
for all the above cases. You can put this in .bashrc
and it will be available every time in shell. Invoke it like prettyjson_s '{"foo": "lorem", "bar": "ipsum"}'
.
Note that in Python 3.5+ the JSON object is no longer sorted by default. To sort, add the --sort-keys
flag to the end. I.e. ... | python -m json.tool --sort-keys
.
How to format JSON in shell script?
You can use: jq
It’s very simple to use and it works great! It can handle very large JSON structures, including streams. You can find their tutorials here.
Usage examples:
$ jq --color-output . file1.json file1.json | less -R
$ command_with_json_output | jq .
$ jq # stdin/"interactive" mode, just enter some JSON
$ jq <<< '{ "foo": "lorem", "bar": "ipsum" }'
{
"bar": "ipsum",
"foo": "lorem"
}
Or use jq
with identity filter:
$ jq '.foo' <<< '{ "foo": "lorem", "bar": "ipsum" }'
"lorem"
Answer #3:
I use the “space” argument of JSON.stringify
to pretty-print JSON in JavaScript.
Examples:
// Indent with 4 spaces
JSON.stringify({"foo":"lorem","bar":"ipsum"}, null, 4);
// Indent with tabs
JSON.stringify({"foo":"lorem","bar":"ipsum"}, null, '\t');
From the Unix command-line with Node.js, specifying JSON on the command line:
$ node -e "console.log(JSON.stringify(JSON.parse(process.argv[1]), null, '\t'));" \
'{"foo":"lorem","bar":"ipsum"}'
Returns:
{
"foo": "lorem",
"bar": "ipsum"
}
From the Unix command-line with Node.js, specifying a filename that contains JSON, and using an indent of four spaces:
$ node -e "console.log(JSON.stringify(JSON.parse(require('fs') \
.readFileSync(process.argv[1])), null, 4));" filename.json
Using a pipe:
echo '{"foo": "lorem", "bar": "ipsum"}' | node -e \
"\
s=process.openStdin();\
d=[];\
s.on('data',function(c){\
d.push(c);\
});\
s.on('end',function(){\
console.log(JSON.stringify(JSON.parse(d.join('')),null,2));\
});\
"
Python script to format JSON in a shell script:
Thanks to very helpful pointers mentioned in other answers, here’s a slightly enhanced script I’ve come up with:
#!/usr/bin/python
"""
Convert JSON data to human-readable form.
Usage:
prettyJSON.py inputFile [outputFile]
"""
import sys
import simplejson as json
def main(args):
try:
if args[1] == '-':
inputFile = sys.stdin
else:
inputFile = open(args[1])
input = json.load(inputFile)
inputFile.close()
except IndexError:
usage()
return False
if len(args) < 3:
print json.dumps(input, sort_keys = False, indent = 4)
else:
outputFile = open(args[2], "w")
json.dump(input, outputFile, sort_keys = False, indent = 4)
outputFile.close()
return True
def usage():
print __doc__
if __name__ == "__main__":
sys.exit(not main(sys.argv))
And finally,
A simple bash script for pretty JSON printing:
json_pretty.sh
#/bin/bash
grep -Eo '"[^"]*" *(: *([0-9]*|"[^"]*")[^{}\["]*|,)?|[^"\]\[\}\{]*|\{|\},?|\[|\],?|[0-9 ]*,?' | awk '{if ($0 ~ /^[}\]]/ ) offset-=4; printf "%*c%s\n", offset, " ", $0; if ($0 ~ /^[{\[]/) offset+=4}'
Example:
cat file.json | json_pretty.sh
Hope you learned something from this post.
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