Sublime Text 2 plugin; copys multiple selections linewise to the clipboard an prepends the line numbers

Context.sublime-menu

[
	{ "caption": "Copy with line numbers", "command": "copy_with_line_numbers" }
] 

copy_with_line_numbers.py

# Source and idea: http://sublimetext.userecho.com/topic/54873

import sublime
import sublime_plugin


class CopyWithLineNumbersCommand(sublime_plugin.TextCommand):
    def run(self, edit):
        sels = self.view.sel()

        # To print all the line numbers with the same lenght
        max_line_num = self.get_line_num(sels[-1].end())
        max_line_num_len = len(str(max_line_num))
        format_string = "%0" + str(max_line_num_len) + "d: %s\n"

        # Assign output
        output = "File: %s\n" % (self.view.file_name() or '')
        is_followup = False
        for sel in sels:
            if is_followup:
                output += "-" * (max_line_num_len + 1) + "\n"
            else:
                is_followup = True

            sel = self.view.line(sel)  # Extend selection to full lines
            first_line_num = self.get_line_num(sel.begin())
            lines = self.view.substr(sel).split("\n")  # Considers all line breaks
            for i, line in enumerate(lines):
                output += format_string % (first_line_num + i, line)

        # Do "output"
        sublime.set_clipboard(output)

    def get_line_num(self, point):
        return self.view.rowcol(point)[0] + 1