Originální popis anglicky:
sync - synchronize data on disk with memory
sync [--help] [--version]
sync writes any data buffered in memory out to disk. This can include
(but is not limited to) modified superblocks, modified inodes, and delayed
reads and writes. This must be implemented by the kernel; The
sync
program does nothing but exercise the
sync(2) system call.
The kernel keeps data in memory to avoid doing (relatively slow) disk reads and
writes. This improves performance, but if the computer crashes, data may be
lost or the filesystem corrupted as a result.
sync ensures that
everything in memory is written to disk.
sync should be called before the processor is halted in an unusual manner
(e.g., before causing a kernel panic when debugging new kernel code). In
general, the processor should be halted using the
shutdown(8) or
reboot(8) or
halt(8) commands, which will attempt to put the
system in a quiescent state before calling
sync(2). (Various
implementations of these commands exist; consult your documentation; on some
systems one should not call
reboot(8) and
halt(8) directly.)
- --help
- Print a usage message on standard output and exit
successfully.
- --version
- Print version information on standard output, then exit
successfully.
- --
- Terminate option list.
The variables LANG, LC_ALL, LC_CTYPE, and LC_MESSAGES have the usual meaning.
POSIX 1003.2
On Linux,
sync is only guaranteed to schedule the dirty blocks for
writing; it can actually take a short time before all the blocks are finally
written. The
reboot(8) and
halt(8) commands take this into
account by sleeping for a few seconds after calling
sync(2).
This page describes
sync as found in the fileutils-4.0 package; other
versions may differ slightly.
sync(2),
halt(8),
reboot(8),
update(8)
