Matching one non-numeric character | LinuC Level 1 101 Exam original practice question

1.02.2Basic

The directory contains node1.conf, nodeA.conf, and node_.conf.

Select names whose character after node is one non-digit.

Which Bash pattern is appropriate?

Hint 1: Focus on the requirement

Look for a negated character set rather than an unrestricted one-character wildcard.

Hint 2: Key terms

Review the short command and filesystem definitions before comparing the choices.

Negated set: A glob set that matches a character outside the listed members.
Bracket negation: The Bash convention that places a negation marker at the start of a bracket expression.
Any-one-character match: A pattern that accepts one character without restricting its kind.
Regular expression: A pattern language whose metacharacter meanings differ from shell globs.

Detailed explanation

Incorrectnode[0-9].conf

Incorrect. [0-9] matches digits.

Incorrectnode?.conf

Incorrect. ? would match both digits and non-digits.

Correctnode[!0-9].conf

Correct. node[!0-9].conf selects one non-digit character.

角括弧先頭の!が数字範囲を否定し、数字以外の1文字へ一致する。

Incorrectnode*.conf

Incorrect. * allows zero or more characters and is too broad.

An example you can run in a temporary verification environment.

tmp=$(mktemp -d); touch "$tmp/node1.conf" "$tmp/nodeA.conf" "$tmp/node_.conf"; (cd "$tmp" && printf '%s\n' node[!0-9].conf); rm -rf "$tmp"

nodeA.conf
node_.conf

Environment: Bash 5.x / 一時ディレクトリ
Use disposable files and directories for destructive or timestamp-related checks.
Command details can vary slightly between GNU and non-GNU implementations.

Foundation review

The negated bracket expression excludes digits while still consuming exactly one character.

Test a digit, a letter, and an underscore to confirm which names are selected.

Question IDKL-101-400

EnvironmentBash 5.x / 一時ディレクトリ

Last technical review2026-08-13

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