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|
.TH SAVECORE 8
.CT 1 sa_auto
.SH NAME
savecore \- save a core image of the operating system
.SH SYNOPSIS
.B /etc/savecore
.I target
.I dump
.SH DESCRIPTION
.I Savecore
copies the core image
saved after an operating system crash
to an ordinary file.
This is worth doing
so that the crash image will not be overwritten
immediately by another crash,
or sometimes because the crash image was written
in a place where normal system operation will overwrite it
(e.g. in the swap area).
.PP
The crash image is taken from
.I dump
and written to
.IR target .
If
.I target
exists and is a directory,
the image is copied to
a file in that directory
with the first nonexistent name
in the sequence
.BR "z.0 z.1 z.2 ..." ;
otherwise
.I target
is created or overwritten.
.PP
The crash image to be copied
is checked for a magic number
in a known location.
If the magic number is correct,
it is followed by the size of the image,
and the time it was written;
these numbers are printed
before the dump is copied.
If the magic number is wrong,
the image is not copied.
.I Savecore
overwrites the magic number in
.I dump
after a successful copy.
.PP
The program runs faster
if
.I dump
is the raw device.
.PP
For compatibility with an older program of the same name,
the
.I dump
argument may be omitted;
.I savecore
will noisily examine each device specified for swapping in
.IR fstab (5)
and each of several popular default swap devices
for a valid magic number.
The first device that looks right
is taken to be the crash image.
.PP
.I Savecore
is usually called when the system is booted,
from
.IR rc (8).
.SH EXAMPLE
.EX
/etc/savecore /tmp/dump /dev/rra11
.EE
.SH SEE ALSO
.IR reboot (8)
.SH BUGS
The argument convention
(the file to be written comes first)
is unfortunate;
it stems from compatibility.
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