runme.py

Description

Solution

1. Step 1Run the script
   Execute runme.py with the Python 3 interpreter. The script prints the flag directly to stdout -- no additional input is needed.
   python3 runme.pyCopied!
   Learn more

   Python is an interpreted language -- scripts are not compiled to native machine code in advance but are read and executed line by line by the Python interpreter. Running a script requires explicitly invoking the interpreter: python3 runme.py tells the shell to start the Python 3 interpreter and pass it the file as input.

   The distinction between python3 and python matters: on many modern Linux and macOS systems, the python command points to Python 2 (now end-of-life), while python3 explicitly invokes Python 3. Always use python3 unless you know the script requires Python 2.

   On Unix-like systems, a script can be made directly executable by:

   • Adding a shebang line at the top: #!/usr/bin/env python3
   • Granting execute permission: chmod +x runme.py
   • Running it directly: ./runme.py

   The shebang (#!) tells the kernel which interpreter to use for the file. CTF scripts often lack this, requiring you to invoke the interpreter manually -- which is always safe and explicit.

Flag

picoCTF{...}

The simplest possible challenge -- Python scripts must be explicitly executed with the interpreter; they do not run on their own by double-clicking in most CTF environments.