Sublime Text plugin "Count Duplicates". Adds command in the Edit main menu that counts number of duplicate rows in a file and prints it in the first left column.

count_dublicates.py

import itertools

import sublime
import sublime_plugin


class CountDuplicatesCommand(sublime_plugin.TextCommand):
    def run(self, edit):
        v = self.view
        
        result = []
        allcontent = sublime.Region(0, v.size())
        lines = sorted(v.substr(allcontent).split('\n'))

        for key, rows in itertools.groupby(lines):
            result.append((sum(1 for r in rows), key))

        result.sort(key=lambda tup: tup[0], reverse=True)
        output = '\n'.join([str(r[0]) + ' ' + r[1] for r in result])

        self.view.replace(edit, allcontent, output)

Main.sublime-menu

[  
    {  
        "id": "edit",  
        "children":  
        [  
            { "command": "count_duplicates" }  
        ]  
    }    
]

RESULT

7 
1         
1             result.append((sum(1 for r in rows), key))
1         allcontent = sublime.Region(0, v.size())
1         for key, rows in itertools.groupby(lines):
1         lines = sorted(v.substr(allcontent).split('\n'))
1         output = '\n'.join([str(r[0]) + ' ' + r[1] for r in result])
1         result = []
1         result.sort(key=lambda tup: tup[0], reverse=True)
1         self.view.replace(edit, allcontent, output)
1         v = self.view
1     def run(self, edit):
1 class CountDuplicatesCommand(sublime_plugin.TextCommand):
1 import itertools
1 import sublime
1 import sublime_plugin

Thank you the this wonderfull tool!