1 .\" Reboot/halt and Linux information extracted from Rick Faith's original
2 .\" sync(8) manpage, dating back to the Linux 0.99 days. The Linux-specific
3 .\" information is attributed to Linus Torvalds
4 .\" Copyright 1992, 1993 Rickard E. Faith (faith@cs.unc.edu)
6 .\" %%%LICENSE_START(GPL_NOVERSION_ONELINE)
7 .\" May be distributed under the GNU General Public License
10 .TH SYNC 8 1998-11-01 "GNU" "Linux Programmer's Manual"
12 sync \- synchronize data on disk with memory
14 .B "sync [\-\-help] [\-\-version]"
17 writes any data buffered in memory out to disk.
18 This can include (but is not limited to) modified superblocks,
19 modified inodes, and delayed reads and writes.
20 This must be implemented by the kernel;
23 program does nothing but exercise the
27 The kernel keeps data in memory to avoid doing (relatively slow) disk
29 This improves performance, but if the computer
30 crashes, data may be lost or the file system corrupted as a result.
32 ensures that everything in memory is written to disk.
35 should be called before the processor is halted in an unusual manner
36 (e.g., before causing a kernel panic when debugging new kernel code).
37 In general, the processor should be halted using the
43 commands, which will attempt to put the system in a quiescent state
46 (Various implementations of these commands exist; consult your
47 documentation; on some systems one should not call
55 Print a usage message on standard output and exit successfully.
58 Print version information on standard output, then exit successfully.
61 Terminate option list.
63 The variables \fBLANG\fP, \fBLC_ALL\fP, \fBLC_CTYPE\fP,
64 and \fBLC_MESSAGES\fP have the usual meaning.
70 is only guaranteed to schedule the dirty blocks for writing; it can
71 actually take a short time before all the blocks are finally written.
76 commands take this into account by sleeping for a few seconds after
82 as found in the file\%utils-4.0 package;
83 other versions may differ slightly.