Running the next command only on success | LPIC-1 101-500 Exam original practice question

103.1Basic

Use test -f app.conf to check whether app.conf exists as a regular file.

Run echo READY only when the check succeeds.

Which command list is correct?

Hint 1: Compare the execution conditions

Compare both a successful check and an unsuccessful check. A READY line in the successful case alone does not show whether the second command was conditional.

Hint 2: Key terms

Separate the exit status from the condition for executing the next command.

Exit status: A numeric result used by the shell: zero denotes success and a nonzero value denotes non-success.
test -f: A condition that checks whether a path exists as a regular file, rather than merely existing as a directory.
&&: The AND-list operator that runs its right-hand command only after a zero exit status on the left.
Semicolon: A separator that waits for the preceding command and then continues regardless of its result.
&: The operator that runs the preceding command asynchronously without waiting for its result.
$?: The special parameter that reports the status of the most recently completed command or list.

Detailed explanation

Correcttest -f app.conf && echo READY

Correct. echo runs only when test reports success.

A regular file makes test return zero, allowing the display command to run. An absent path or a directory does not. Comparing both outcomes establishes the required conditional behavior.

Incorrecttest -f app.conf || echo READY

Incorrect. || runs its right-hand side when the test fails.

The OR-list operator runs the display when the test is nonzero. It therefore prints READY when the regular-file check fails, reversing the required condition.

Incorrecttest -f app.conf; echo READY

Incorrect. ; runs echo regardless of the test result.

The semicolon waits for the test but does not use its status as a condition. READY appears for both successful and unsuccessful checks, which a success-only example would fail to distinguish.

Incorrecttest -f app.conf & echo READY

Incorrect. & starts commands asynchronously and does not express a success condition.

The test runs in the background and echo does not wait for its result before executing. Seeing READY does not establish that the background check succeeded; its result would need separate collection with wait.

Try it yourself

An example you can run in a temporary verification environment.

LAB_DIR=$(mktemp -d) || exit 1
(
  cd "$LAB_DIR" || exit 1
  : > app.conf
  mkdir dir.conf || exit 1
  test -f app.conf && printf 'present: READY\n'
  test -f missing.conf && printf 'missing: READY\n'
  printf 'missing status=%s\n' "$?"
  test -f dir.conf && printf 'directory: READY\n'
  printf 'directory status=%s\n' "$?"
  rm -- app.conf
  rmdir -- dir.conf
)
rmdir -- "$LAB_DIR"

Official references

Expected result

present: READY
missing status=1
directory status=1

Key points

Short-circuit evaluation with &&
Exit status 0
Conditional execution

Notes

Environment: Bash 5.2 / GNU coreutils in a fresh process with errexit off. Compare a regular file, an absent path, and a directory inside a newly created temporary directory.
Use a fresh Bash process and names inside the newly created temporary directory. Cleanup names only the created file and empty directories; it does not use recursive removal.
Read $? immediately after the relevant AND list. An intervening command replaces the status being observed.

Foundation review

Observe both branches

With a regular file, &&, a semicolon, and a background operator can all produce READY. Use absent-path and directory cases to check when the display is skipped.

Status is different from output

test normally reports its decision through a numeric exit status rather than printing a value. The condition for && is zero, not text written to standard output.

Check the file type

The -f condition means a regular file. An existing directory is not sufficient for that condition.

Question IDKP-103-020

EnvironmentBash 5.2 / GNU coreutils in a fresh process with errexit off. Compare a regular file, an absent path, and a directory inside a newly created temporary directory.

Last technical review2026-11-02

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