general renaming script: change the script's file name to change how it works

x2y.py

#!/usr/bin/env python3
"""
uses the script's name to determine how to rename files in the directory it exists in
e.g. x2y.py -> renames files named with *.x suffixes to now end with *.y suffixes
or more usefully: jpeg2jpg.py -> renames files named with .jpeg suffix to end with .jpg

lowercases the matching suffix (e.g. jpeg2jpg.py will match both JPEG and jpeg)
"""
import sys
import os

scriptname = sys.argv[0]
matching_suffix = scriptname.split("2")[0]
dest_suffix  = scriptname.split("2")[1].split(".")[0]
print("matching on *.{}".format(matching_suffix))
print("renaming to *.{}".format(dest_suffix))

fpath = os.getcwd()
counts = 0
with os.scandir(fpath) as it:
    for entry in it:
        if not entry.name.startswith('.') and entry.is_file():
            if entry.name.lower().endswith(matching_suffix):
                new_name = "{}.{}".format(entry.name[:-1 * (1+len(matching_suffix))], dest_suffix)
                old_fullpath = os.path.join(fpath, entry.name)
                new_fullpath = os.path.join(fpath, new_name)
                try:
                    os.rename(old_fullpath, new_fullpath)
                    counts += 1
                except:
                    print("file {} already existed", new_fullpath)

print("renamed {} files".format(counts))