With default value, in help message

[podhmo]

fix #179

[podhmo]

$ dictknife -h
usage: dictknife [-h]
                 [--log {CRITICAL,FATAL,ERROR,WARN,WARNING,INFO,DEBUG,NOTSET}]
                 [-q] [--debug] [--compact] [--flatten]
                 [--unescape {unicode,url}]
                 {cat,concat,transform,diff,shape,shrink,mkdict} ...

optional arguments:
  -h, --help            show this help message and exit
  --log {CRITICAL,FATAL,ERROR,WARN,WARNING,INFO,DEBUG,NOTSET}
                        - (default: INFO)
  -q, --quiet           - (default: False)
  --debug               - (default: False)
  --compact             - (default: False)
  --flatten             - (default: False)
  --unescape {unicode,url}
                        - (default: None)

subcommands:
  {cat,concat,transform,diff,shape,shrink,mkdict}
    cat
    concat              concat dicts
    transform           transform dict
    diff                diff dict
    shape               shape
    shrink              shrink
    mkdict

[podhmo]

$ dictknife cat -h
usage: dictknife cat [-h] [--slurp] [--size SIZE] [--dst DST]
                     [-f {yaml,json,toml,csv,tsv,raw,env,md,markdown,spreadsheet}]
                     [-i {yaml,json,toml,csv,tsv,raw,env,md,markdown,spreadsheet}]
                     [-o {yaml,json,toml,csv,tsv,raw,env,md,markdown,spreadsheet}]
                     [--encoding ENCODING]
                     [--errors {strict,ignore,replace,surrogateescape,xmlcharrefreplace,backslashreplace,namereplace}]
                     [-S] [--merge-method {addtoset,append,merge,replace}]
                     [files [files ...]]

positional arguments:
  files                 - (default: [<_io.TextIOWrapper name='<stdin>' mode='r' encoding='utf-8'>])

optional arguments:
  -h, --help            show this help message and exit
  --slurp               - (default: False)
  --size SIZE           - (default: None)
  --dst DST             - (default: None)
  -f {yaml,json,toml,csv,tsv,raw,env,md,markdown,spreadsheet}, --format {yaml,json,toml,csv,tsv,raw,env,md,markdown,spreadsheet}
                        - (default: None)
  -i {yaml,json,toml,csv,tsv,raw,env,md,markdown,spreadsheet}, --input-format {yaml,json,toml,csv,tsv,raw,env,md,markdown,spreadsheet}
                        - (default: None)
  -o {yaml,json,toml,csv,tsv,raw,env,md,markdown,spreadsheet}, --output-format {yaml,json,toml,csv,tsv,raw,env,md,markdown,spreadsheet}
                        - (default: None)
  --encoding ENCODING   input encoding. (e.g. utf-8, cp932, ...) (default: None)
  --errors {strict,ignore,replace,surrogateescape,xmlcharrefreplace,backslashreplace,namereplace}
                        see pydoc codecs.Codec (default: None)
  -S, --sort-keys       - (default: False)
  --merge-method {addtoset,append,merge,replace}
                        - (default: addtoset)

extra arguments: (with --extra<option>)
  for --output-format=csv:
    --fullscan  full scan for guessing headers

  for --output-format=tsv:
    --fullscan  full scan for guessing headers