Here's one of mine. I got annoyed at the complexity of other command line spellcheckers I tried and replaced them with this simple python script for when I just want to check if a single word is correct:

#!/usr/bin/env python3

import sys

try:
  query = sys.argv[1].lower()
except Exception:
  print("Usage: spellcheck <word>")
  exit(1)

with open("/usr/share/dict/words") as f:
  words = f.readlines()

words = [x.strip().lower() for x in words if len(x.strip()) > 0]

if not query in words:
  print("Not in dictionary -- probably a typo")
  exit(1)
else:
  print("OK")
  exit(0)