Passing a file as standard input | LinuC Level 1 101 Exam original practice question

1.03.3Basic

Give sort the contents of unsorted.txt through standard input.

Do not pass the filename as sort's ordinary argument.

Which command is appropriate?

Hint 1: Focus on the requirement

Connect the named file to the command's standard input.

Hint 2: Key terms

Review the short stream and redirection definitions before comparing the choices.

Standard input: The stream a command reads by default.
Input redirection: A shell connection from a file to standard input.
Less-than operator: The shell symbol that supplies a file as standard input.
Read operation: Receiving bytes from an input stream.

Detailed explanation

Incorrectsort > unsorted.txt

Incorrect. > redirects sort's stdout and would overwrite the file.

Incorrectsort >> unsorted.txt

Incorrect. >> appends sort's stdout to the file.

Correctsort < unsorted.txt

Correct. sort < unsorted.txt connects the file to standard input.

Incorrectsort 2< unsorted.txt

Incorrect. 2< operates on file descriptor 2, not normal standard input.

An example you can run in a temporary verification environment.

tmp=$(mktemp); printf 'b\na\n' >"$tmp"; sort <"$tmp"; rm -f "$tmp"

a
b

Environment: Bash 5.x / GNU sort / 一時ファイル
Use temporary files and harmless commands for stream experiments.
Shell redirection syntax and xargs behavior should be checked on the target shell implementation.

Foundation review

Input redirection lets a command that normally reads a terminal consume a file instead.

Compare redirected input with equivalent piped input using a harmless reader.

Question IDKL-101-468

EnvironmentBash 5.x / GNU sort / 一時ファイル

Last technical review2026-08-13

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