Changing the environment for one command | LPIC-1 102-500 Exam original practice question

105.1Standard

Apply LC_ALL=C only to one sort invocation of names.txt.

Do not change LC_ALL in the current shell.

Which command is appropriate?

Hint 1: Focus on shell scope

Separate login and non-login startup files, current-shell changes, environment inheritance, and command lookup before comparing the choices.

Hint 2: Key terms

Review the short definitions of shell startup files, variables, aliases, functions, and command lookup.

prefix assignment: NAME=value placed before a command to affect that command's environment only.
command environment: The environment variables received by one command process.
LC_ALL: The locale variable that overrides the other LC_* variables and LANG.
parent shell: The calling shell that keeps its state after a prefixed command exits.

Detailed explanation

Incorrectexport LC_ALL=C; sort names.txt

Incorrect. export leaves LC_ALL=C in the current shell.

IncorrectLC_ALL=C; sort names.txt

Incorrect. A standalone assignment leaves the shell variable defined afterward.

Incorrectsort LC_ALL=C names.txt

Incorrect. LC_ALL=C is treated as a sort argument in that position.

CorrectLC_ALL=C sort names.txt

Correct. The assignment immediately before sort applies only to sort's environment.

An example you can run in a temporary verification environment.

bash --noprofile --norc -c 'unset LC_ALL; LC_ALL=C sh -c '\''printf "child=%s\n" "$LC_ALL"'\''; printf "parent=%s\n" "${LC_ALL-unset}"'

child=Cの後にparent=unset

Foundation review

Check whether the command acts on the current shell, a new process, an existing process, or a file.

Use the supplied command and compare the output with the expected result.

Question IDKP-105-607

EnvironmentGNU Bash 5.2 / 一時子プロセス

Last technical review2026-08-13

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