Shell wildcards: Which single wildcard matches exactly one character in UNIX shell globbing?

Introduction / Context:Shell wildcards (globs) expand patterns to filenames and paths. Knowing how ?, , and character classes work is essential for accurate file selection and scripting.

Given Data / Assumptions:

• We are using typical Bourne-like shells (sh, bash, ksh, zsh) with standard globbing.
• We need a wildcard that matches one character only.
• Other glob tokens match sets or arbitrary lengths.

Concept / Approach:The ? wildcard matches exactly one character. The * wildcard matches any number of characters, including none. Character classes [ijk] match exactly one character but limited to the listed set; [!ijk] matches one character not in the set.

Step-by-Step Solution:

Verification / Alternative check:Test with files: touch a1 a2 ab; ls a? matches a1 and a2 but not ab if more characters follow; ls a matches all beginning with a.

Why Other Options Are Wrong:: Matches zero or more characters, not exactly one. [ijk]: One character but restricted to i, j, or k only. [!ijk]: One character not i, j, or k. None of the above: Incorrect since ? is correct.

Common Pitfalls:Confusing shell globs with regular expressions; expecting ? to match directory separators when globbing (it does not cross /).

Final Answer:?