.TH CPIO 5
.CT 1 comm_users
.SH NAME
cpio \- format of cpio archive
.SH DESCRIPTION
The archived files are recorded consecutively, each
preceded by a
.BR header .
The  header
structure, when the
.B \-c
option of
.IR cpio (1)
is not used, is:
.PP
.EX
.ta \w'short 'u +\w'ushort 'u
typdef unsigned short ushort;
struct {
	short	h_magic,
		h_dev;
	ushort	h_ino,
		h_mode,
		h_uid,
		h_gid;
	short	h_nlink,
		h_rdev,
		h_mtime[2],
		h_namesize,
		h_filesize[2];
	char	h_name[h_namesize rounded to word];
} Hdr;
.EE
.PP
When the
.B \-c
option is used, the
.B header
information is printable, as described by the 
.IR printf (3)
call
.IP
.EX
printf(Chdr, "%6o%6o%6o%6o%6o%6o%6o%6o%11lo%6o%11lo%s",
	Hdr.h_magic, Hdr.h_dev, Hdr.h_ino, Hdr.h_mode,
	Hdr.h_uid, Hdr.h_gid, Hdr.h_nlink, Hdr.h_rdev,
	Longtime, Hdr.h_namesize, Longfile, Hdr.h_name
.EE
.PP
.L Longtime
and
.L Longfile
are equivalent to
.L Hdr.h_mtime
and
.LR Hdr.h_filesize ,
respectively.
Every instance of
.L h_magic
contains the octal constant
.LR 070707 .
The items
.L h_dev
through
.L h_mtime
have meanings explained in
.IR  stat (2).
The length of the null-terminated path name
.LR h_name ,
including the null byte,
is given by
.LR h_namesize .
.PP
The last element
of the archive
is a dummy entry for the name
.BR TRAILER!!! ,
with padding to a multiple of 512 bytes.
Special files, directories, and the trailer are recorded
with
.L h_filesize
equal to zero.
.SH "SEE ALSO"
.IR cpio (1), 
.IR find (1), 
.IR stat (2).
.\"	@(#)cpio.4	5.2 of 5/18/82