2to3

2to3 [options] file|directory

2to3 is an automated Python 2 to Python 3 code translator. It parses Python 2 source code and applies "fixers" that transform incompatible syntax and library calls to their Python 3 equivalents.Common transformations include:- print statement to print() function- unicode to str, str to bytes- raw_input() to input()- Iterator methods (.iteritems() to .items())- except Exception, e to except Exception as e- Library renames (urllib, ConfigParser, etc.)2to3 handles most mechanical changes but may require manual review for semantic differences between Python 2 and 3.

-w, --write

Write changes to files

Don't create .bak backup files

Apply specific fixer

Exclude specific fixer

List available fixers

Treat print as a function (skip the print fixer). Useful when the file already uses from __future__ import print_function.

Only fix doctests inside the file.

Write output even for unchanged files (useful with -o).

Append this suffix to output filenames instead of overwriting.

Run in parallel with n processes

Write converted files to directory

More verbose output

2to3 makes syntactic changes but cannot handle all differences. Code behavior may still differ, especially around:- String/bytes handling- Integer division- Dictionary ordering (pre-Python 3.7)- Unicode text processingRunning -w without -n creates .bak files that may clutter version control.Python 2 reached end-of-life in January 2020. For major projects, consider modern porting tools like python-modernize or futurize.

python(1), python3(1), pip(1)