2. Using the Python Interpreter

Python interpreter can be used in interactive mode or in scrips. In interactive mode Python interpreter support GNU Readline library, which provide rich keybinding system.

Personally I have py command-line alias to run python in interactive mode and ipy to run ipython (custom interactive shell).

Below some useful examples:

• python - interactive mode, to exit use: C-d, C-z or quit().
• python -c - execute code
• python -m <module> [arg] - execute module with optional arguments
• python -i [script] - interactive with script execution, can be combined with -c and -m.

Python interpreter support argument parsing. You can use import sys; sys.argv to get current script or module name and arguments (list of strings). Minimal length of sys.argv is 1, which first item is empty if we don’t use any arguments.

In sys.argv also stored -c and -m command line switches (sys.argv[0]) and their arguments. Options found after -c command or -m module are not consumed by the Python interpreter’s option processing but left in sys.argv for the command or module to handle.

In interactive prompt usually for next command used >>> sign, for continuation lines used secondary prompt ....

By default, Python 3 source files are treated as encoded in ==UTF-8==, but standard library only use ASCII characters for identifiers, this convention that any portable code should follow.

Can I use non UTF-8 encoding?
Yes, if you need to set non UTF-8 encoding, use # -*- coding: ENCODING_NAME -*- comment as first line or after shebang:

#!/usr/bin/env python3
# -*- coding: cp1251 -*-
print("Здесь можно использовать кодировку cp1251")