Python · Theory

CLI arguments

Theory

94/268

Command-line args come in sys.argv. argv[0] is the script name. argv[1:] are extra words after python file.py.

Example: python add.py 2 3 → argv is [add.py, 2, 3]. int() them before adding. argparse is the nicer library for real tools.

CLI arguments — output — script name then 5. argv[0] is the file; rest are extra words.

Exam tip

What is argv[0]? Then one tiny add.py idea.

# CLI arguments
import sys
print(sys.argv[0])
args = ["2", "3"]  # like python add.py 2 3
print(int(args[0]) + int(args[1]))

CLI arguments — output: script name then 5. argv[0] is the file; rest are extra words.