MCEdit filter to do find and replace in command blocks, with support for regular expressions.

findandreplaceregex.py

# coding unicode-escape
# Feel free to modify and use this filter however you wish. If you do,
# please give credit to SethBling.
# http://youtube.com/SethBling
# Updated to 1.11 by Onnowhere
# http://youtube.com/Onnowhere2
# Regex support added by AjaxGb
# https://github.com/AjaxGb

import re
from pymclevel import TAG_List
from pymclevel import TAG_Byte
from pymclevel import TAG_Int
from pymclevel import TAG_Compound
from pymclevel import TAG_Short
from pymclevel import TAG_Double
from pymclevel import TAG_String

displayName = "Find and Replace Regex"

inputs = (
	("Find", "string"),
	("Replace", "string"),
	("Use RegEx", True),
)

def perform(level, box, options):
	print("=== Running Find and Replace Regex ===")
	find = options["Find"]
	replace = options["Replace"]
	use_regex = options["Use RegEx"]

	for (chunk, slices, point) in level.getChunkSlices(box):
		for t in chunk.TileEntities:
			x = t["x"].value
			y = t["y"].value
			z = t["z"].value
			
			if x >= box.minx and x < box.maxx and y >= box.miny and y < box.maxy and z >= box.minz and z < box.maxz:
				if t["id"].value == "Control":
					# Catch in case you have not updated all command blocks to 1.11
					t["id"] = TAG_String("minecraft:command_block")
					print("Updated block at", x, y, z, "to 1.11")
					chunk.dirty = True
				if t["id"].value == "minecraft:command_block":
					# Find and replace
					cmd = t["Command"].value
					if use_regex:
						newcmd = re.sub(find, replace, cmd)
					else:
						newcmd = cmd.replace(find, replace)
					if newcmd != cmd:
						print("<<", cmd)
						print(">>", newcmd)
						t["Command"] = TAG_String(newcmd)
						chunk.dirty = True

Credit to SethBling for the original filter, and to Onnowhere for updating it to 1.11.