what's the meaning of ^@ in syslog

Question

One physical machine had shutdown unexpected, there is no any error log about that, only get a large ^@ in one line of /var/log/syslog file such as:

Dec  9 21:50:02 hostname CRON[74324]: (root) MAIL (mailed 716 bytes of output but got status 0x004b from MAT#012)
^@^@^@...large of ^@^@^@Dec 10 09:51:49 hostname systemd[1]: Starting Flush Journal to Persistent Storage...
Dec 10 09:51:49 hostname kernel: [...

Machine shutdowned at Dec 9 21:50 unexpected, and start by manual at Dec 10 09:51:49.

How could I find the root cause of it shutdown unexpected?

Where did it Flush Journal to?

What's the meaning of ^@ in syslog, and how could I read it?

Possible partial duplicate of [System crash - strange chars in syslog](https://unix.stackexchange.com/questions/477537/system-crash-strange-chars-in-syslog) or of [What does ^@^@^@ mean in a text file?](https://unix.stackexchange.com/q/108321) — Kusalananda, Dec 12 '22 at 08:55

score 4 · Accepted Answer · answered Dec 12 '22 at 01:58

4

Those are NUL bytes (i.e. bytes with a numerical value of zero), those should not exist in text files.

The crash caused the file to be extended without the data being written.

answered Dec 12 '22 at 01:58

Simon Richter

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How could I find the couse of crash? – VictorLee Dec 12 '22 at 02:08
As the question about what `^@` means is answered in several other similar questions, anwers to this question should probably focus on the other parts of the question. – Kusalananda Dec 12 '22 at 08:58

what's the meaning of ^@ in syslog

1 Answers1