Question 1

What does truncate do?

Accepted Answer

Shrink or extend a file to a size Sets a file to an exact size. `truncate -s 0 file` empties it without deleting it; extending creates a sparse file.

Question 2

Is truncate dangerous?

Accepted Answer

HIGH risk. Cutting a file shorter permanently discards data beyond the new size. Data past the new size is gone — there is no undo. Truncating a log that a process holds open is usually fine, but truncating a database or data file corrupts it. Check the filename carefully; this runs without confirmation.

Question 3

How can I use truncate more safely?

Accepted Answer

cp app.log app.log.bak && truncate -s 0 app.log — Keep a copy before emptying logrotate -f /etc/logrotate.d/<app> — Let logrotate manage log files

Flag	Meaning
`-s`	New size, e.g. 0, 100M, +1G
`-c`	Do not create missing files