0x03 - writing a Python program

bin 0x03 of LiveOverflow’s binexp series
he moves from C to Python this time shows how to turn boring bash input repetition into a tiny script.

the result?
this lil script:

import sys

if len(sys.argv) == 2:
    print("Knock, knock, {0}".format(sys.argv[1]))
else:
    sys.stderr.write("Usage: {0} <name>\n".format(sys.argv[0]))

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breaking it down (my way)

• sys.argv[] → like argv[] in C, holds command-line arguments
• argv[0] → script name
• argv[1] → the actual input
• sys.stderr.write() → prints error to stderr, not stdout
• .format() → OG string formatting style (not f-strings, but still ✨clean✨ tho i prefer f-string)

basic af, but the feeling of swapping bash repetition for Python?
kinda addicting.

---

run it like this

python3 knock.py lav

Knock, knock, lav

no args?

python3 knock.py

Usage: knock.py <name>

tl;dr

• wrote a python script to handle cli args
• learned to print errors to stderr (like in C)
• replaced bash muscle memory with logic muscle
• realized Python + binaries gonna be a powerful combo

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_{till the next leak :D
~ lav}