.\" Copyright 1992, 1993 Rickard E. Faith (faith@cs.unc.edu)
.\" May be distributed under the GNU General Public License
.TH SYNC 8 "20 November 1993" "Linux 0.99" "Linux Programmer's Manual"
.SH NAME
sync \- flush Linux filesystem buffers
.SH SYNOPSIS
.B sync
.SH DESCRIPTION
.B sync
executes
.BR sync (2),
which flushes the filesystem buffers to disk.
.B sync
should be called before the processor is halted in an unusual manner (i.e.,
before causing a kernel panic when debugging new kernel code).  In general,
the processor should be halted using the
.BR reboot "(8), or " halt (8)
commands, which will attempt to put the system in a quiescent state before
calling
.BR sync (2).

From Linus: "Note that
.B 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.  If
you are doing the
.B sync
with the expectation of killing the machine soon after, please take this
into account and sleep for a few seconds.  [The
.BR reboot (8)
command takes these precautions.]
.SH "SEE ALSO"
.BR sync (2),
.BR update (8),
.BR reboot (8),
.BR halt (8)
.SH AUTHOR
Linus Torvalds (torvalds@cs.helsinki.fi)