A monitoring script must stamp every record it writes with the current time expressed as a plain integer count of seconds since the Unix epoch. Which command prints exactly that value and nothing else?
LPIC-1 Exam 102-500, objective 108. Essential system services easy
Machine-checked — no person has signed for it. This question was read against the source cited below by an automated pass, which found no contradiction. That is a weaker claim than it sounds: the same kind of process wrote the question, so it can confirm its own mistake.
Treat it as a good draft rather than as settled fact, and read the source below before you rely on it. It is not used in mock exams here — only questions a person has signed for are.
How these questions are written — where each question comes from, what the verification ledger records, and what happens when one is found wrong.
The options
Correct date +%s
Correct. The %s conversion prints the number of seconds elapsed since 1970-01-01 00:00:00 UTC, as a single integer with no separators.
Not correct date +%S
Wrong. Uppercase %S is the seconds field of the current wall-clock time, a two-digit number between 00 and 60. The letter case is the whole difference.
Not correct date -s
Wrong. -s (--set) sets the system clock from a time string given as its argument; with no argument it fails. It writes the clock rather than reading it.
Not correct date +%e
Wrong. %e is the day of the month, space-padded, so it yields values from 1 to 31.
Why
A format argument to date begins with a plus sign, and every conversion after it is case-sensitive: %s is epoch seconds, %S is the seconds of the minute, %d is a zero-padded day and %e the space-padded one. Epoch seconds are timezone-independent, which is why they are the usual choice for log stamps and for arithmetic between two times. The reverse conversion is `date -d @1755500000`.
Where this comes from
- Cited
- manual page date(1)
Practise this
Reading one question is not practice. The trainer will draw a short set from objective 108 and space the ones you get wrong.
More questions on this objective
- You corrected the running system's clock with `date -s`, but after the next power cycle the machine came back with the old wrong time. Which command copies the corrected system clock into the hardware (RTC) clock? machine-checked
- On a systemd-based distribution, which file determines the local time zone used by the C library when formatting times? machine-checked
- A host runs chrony as its NTP client. Which command shows the list of time sources chrony is currently talking to and how it rates each one? machine-checked
- In /etc/ntp.conf you find the line `server 0.pool.ntp.org iburst`. What does the `iburst` keyword do? machine-checked
- A minimal systemd host synchronises its clock with systemd-timesyncd. Which statement about that service is accurate? machine-checked
- On a systemd host, type the single command that turns on automatic network time synchronisation (do not include a path). machine-checked