z/OS V1R9.0 UNIX System Services Command ... - Christian Grothoff

tar
Description of the Header Files
In the headers:
v The name field contains the name of the archived file. On USTAR format archives,
the value of the prefix field, if non-null, is prefixed to the name field to allow
names longer than 100 characters.
v The magic, uname, and gname fields are null-terminated character strings
v The name, linkname, and prefix fields are null-terminated unless the full field is
used to store a name (that is, the last character is not null).
v All other fields are zero-filled octal numbers, in ASCII. Trailing nulls are present
for these numbers, except for the size, mtime, and version fields.
v prefix is null unless the filename exceeds 100 characters.
v The size field is zero if the header describes a link.
v The chksum field is a checksum of all the bytes in the header, assuming that the
chksum field itself is all blanks.
v For USTAR, the typeflag field is a compatible extension of the link field of the
older tar format. The following values are recognized:
Flag File Type
0 or null Regular file
1 Link to another file already archived
2 Symbolic link
3 Character special file
4 Block special file (not supported)
5 Directory
6 FIFO special file
7 Reserved
S z/OS extended USTAR special header
T z/OS extended USTAR special header summary (S and T are
z/OS extensions. See “z/OS extended USTAR support” on page
498 for more information.)
A–Z Available for custom usage
v In USTAR format, the uname and gname fields contain the name of the owner and
group of the file, respectively.
Compressed tar archives are equivalent to the corresponding archive being passed
to a 14-bit compress command.
Related Information
The cpio and tar commands
utmpx — Format of login accounting files
Description
Login accounting information is stored in two files:
v /etc/utmpx holds the current state of each item being accounted
v /etc/wtmp maintains the history of changes to each accounting item
924 z/OS V1R9.0 UNIX System Services Command Reference