glob_path
=========
Finds all the pathnames matching the pattern.

Function Arguments
------------------
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   :widths: 20 10 60
   :header-rows: 1
   :align: left

   * - Name
     - Type
     - Description

   * - pathname
     - str
     - The file path of target file.

   * - key
     - str
     - (optional; default: ``'path'``) The key of the result.

   * - filename_only
     - bool
     - (optional; default: ``False``) True to return the file name instead of the whole path.

Description
-----------
The output of this function is a dictionary with only one entry, whose key
is specified by the argument ``key`` and the value is the matched path name
(or the file name if ``filename_only=true``).

Examples
--------
Let's assume that there are files::

  /tmp/aa/00.txt
  /tmp/aa/01.txt
  /tmp/aa/02.tgz
  /tmp/aa/03.tgz

Then the probe statement ::

  {
    "eval": "glob_path:/tmp/aa/*.txt"
  }

will have the corresponding probed results ::

  [
    {
      "path": "/tmp/aa/00.txt"
    },
    {
      "path": "/tmp/aa/01.txt"
    }
  ]

And the probe statement ::

  {
    "eval": {
      "glob_path": {
        "pathname": "/tmp/aa/00.txt",
        "filename_only": true,
        "key": "filename"
      }
    }
  }

will have the corresponding probed results ::

  [
    {
      "filename": "00.txt"
    }
  ]

And the probe statement ::

  {
    "eval": "glob_path:/tmp/aa/no_such_file.txt"
  }

will have the corresponding probed results ::

  [
  ]