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      1 r"""Command-line tool to validate and pretty-print JSON
      2 
      3 Usage::
      4 
      5     $ echo '{"json":"obj"}' | python -m json.tool
      6     {
      7         "json": "obj"
      8     }
      9     $ echo '{ 1.2:3.4}' | python -m json.tool
     10     Expecting property name enclosed in double quotes: line 1 column 3 (char 2)
     11 
     12 """
     13 import sys
     14 import json
     15 
     16 def main():
     17     if len(sys.argv) == 1:
     18         infile = sys.stdin
     19         outfile = sys.stdout
     20     elif len(sys.argv) == 2:
     21         infile = open(sys.argv[1], 'rb')
     22         outfile = sys.stdout
     23     elif len(sys.argv) == 3:
     24         infile = open(sys.argv[1], 'rb')
     25         outfile = open(sys.argv[2], 'wb')
     26     else:
     27         raise SystemExit(sys.argv[0] + " [infile [outfile]]")
     28     with infile:
     29         try:
     30             obj = json.load(infile)
     31         except ValueError, e:
     32             raise SystemExit(e)
     33     with outfile:
     34         json.dump(obj, outfile, sort_keys=True,
     35                   indent=4, separators=(',', ': '))
     36         outfile.write('\n')
     37 
     38 
     39 if __name__ == '__main__':
     40     main()
     41