On Unix/Linux, which command makes all files and subdirectories within the directory named 'progs' executable by all users (recursively)?

Introduction / Context:
Permissions control who can read, write, and execute files. When distributing scripts or binaries within a directory tree, administrators often need to grant execute permission broadly so that users can run these files without permission errors. A recursive and user-agnostic approach is typically used.

Given Data / Assumptions:

• Target directory is 'progs' with nested content.
• You want execute permission for user, group, and others.
• You want to apply permissions recursively.

Concept / Approach:
'chmod -R a+x progs' applies the execute bit for all classes (a = u,g,o) on every file and subdirectory under 'progs'. This grants traversal on directories and execution on executable files and scripts. It does not remove other permissions; it only adds +x. Alternatives shown are either invalid or set inappropriate modes.

Step-by-Step Solution:

Verification / Alternative check:
Run a representative script or binary to confirm it executes for non-owner accounts. Check directory traversal by ensuring 'x' is set on directories users must enter.

Why Other Options Are Wrong:

• chmod -R 222 progs: Sets write-only bits, removing execute; unusable.
• chmod -1 a+x progs: Invalid syntax; '-1' is not a valid option.
• chmod -x a+x progs: Conflicting and nonsensical combined flags.
• None of the above: Incorrect because the first option is right.

Common Pitfalls:
Blindly setting execute on non-executable documents, or forgetting that directories require 'x' for traversal while files require 'x' for execution.

Final Answer:
chmod -R a+x progs