|
|
HTML color codes and names
About tar
Create tape archives and add or extract files.
Syntax
tar c [ bBeEfFhiklnopPqvwX [ 0-7 ] ] [ block ] [ tarfile ] [
exclude-file ] {-I include-file | -C directory | file | file }
tar r [ bBeEfFhiklnqvw [ 0-7 ] ] [ block ] {-I include-file | -C
directory | file | file }
tar t [ BefFhiklnqvX [ 0-7 ] ] [ tarfile ] [ exclude-file ] {-I
include-file | file } ...
tar u [ bBeEfFhiklnqvw [ 0-7 ] ] [ block ] [ tarfile ] file
...
tar x [ BefFhiklmnopqvwX [ 0-7 ] ] [ tarfile ] [ exclude-file ] [
file ... ]
| c |
Create. Writing begins at the beginning of the
tarfile, instead of at the end. |
| r |
Replace. The named file s are written at the
end of the tarfile. A file created with extended headers must
be updated with extended headers (see E flag under Function
Modifiers). A file created without extended headers cannot be
modified with extended headers. |
| t |
Table of Contents. The names of the specified
files are listed each time they occur in the tar file. If no
file argument is given, the names of all files in the tarfile
are listed. With the v
function modifier, additional
information for the specified files is displayed. |
| u |
Update. The named file s are written at the end
of the tarfile if they are not already in the tar file, or if
they have been modified since last written to that tarfile. An
update can be rather slow. A tarfile created on a 5.x system
cannot be updated on a 4.x system. A file created with
extended headers must be updated with extended headers (see E
flag under Function Modifiers). A file created without
extended headers cannot be modified with extended
headers. |
| x |
Extract or restore. The named file s are
extracted from the tarfile and written to the directory
specified in the tarfile, relative to the current directory.
Use the relative path names of files and directories to be
extracted. If a named file matches a directory whose contents
has been writ ten to the tarfile, this directory is
recursively extracted. The owner, modification time, and mode
are restored (if possible); otherwise, to restore owner, you
must be the super-user. Character special and block-special
devices (created by mknod(1M)) can only be extracted by the
super user. If no file argument is given, the entire content
of the tarfile is extracted. If the tar- file contains several
files with the same name, each file is written to the
appropriate directory, overwriting the previous one. Filename
substitu tion wildcards cannot be used for extracting files
from the archive; rather, use a command of the form:
tar xvf... /dev/rmt/0 `tar tf... /dev/rmt/0 | grep
'pattern' `
When extracting tapes created with the r or u functions,
directory modification times may not be set correctly. These
same functions cannot be used with many tape drives due to
tape drive limitations such as the absence of backspace or
append capabilities.
When using the r, u, or x functions or the X function
modifier, the named files must match exactly the corresponding
files in the tarfile. For example, to extract ./thisfile, you
must specify ./thisfile, and not thisfile. The t function
displays how each file was archived. |
Function Modifiers
The characters below may be used in
conjunction with the letter that selects the desired function.
| b |
Blocking Factor. Use when reading or writing to
raw magnetic archives (see f below). The block argument
specifies the number of 512-byte tape blocks to be included in
each read or write operation performed on the tarfile. The
minimum is 1, the default is 20. The maximum value is a
function of the amount of memory available and the blocking
requirements of the specific tape device involved (see
mtio(7I) for details.) The maximum cannot exceed INT_MAX/512
(4194303).
When a tape archive is being read, its actual blocking
factor will be automatically detected, provided that it is
less than or equal to the nominal blocking factor (the value
of the block argument, or the default value if the b modifier
is not specified). If the actual blocking factor is greater
than the nominal blocking factor, a read error will result.
See Example 5 in Examples. |
| B |
Block. Force tar to perform multiple reads (if
necessary) to read exactly enough bytes to fill a block. This
function modifier enables tar to work across the Ethernet,
since pipes and sockets return partial blocks even when more
data is coming. When reading from standard input, '-', this
function modifier is selected by default to ensure that tar
can recover from short reads. |
| e |
Error. Exit immediately with a positive exit
status if any unexpected errors occur. The SYSV3 environment
variable overrides the default behavior. (See ENVIRONMENT
section below.) |
| E |
Write a tarfile with extended headers. (Used
with c, r, or u options; ignored with t or x options.) When a
tarfile is written with extended headers, the modification
time is maintained with a granularity of microseconds rather
than seconds. In addition, filenames no longer than PATH_MAX
characters that could not be archived without E, and file
sizes greater than 8GB, are supported. The E flag is required
whenever the larger files and/or files with longer names, or
whose UID/GID exceed 2097151, are to be archived, or if time
granularity of microseconds is desired. |
| f |
File. Use the tarfile argument as the name of
the tarfile. If f is specified, /etc/default/tar is
not
searched. If f is omitted, tar will use the device indicated
by the TAPE environment variable, if set; otherwise, it will
use the default values defined in /etc/default/tar. If the
name of the tarfile is '-', tar writes to the standard output
or reads from the standard input, whichever is appropriate.
tar can be used as the head or tail of a pipeline. tar can
also be used to move hierarchies with the command:
example% cd fromdir; tar cf - .| (cd todir; tar xfBp
-) |
| F |
With one F argument, tar excludes all
directories named SCCS and RCS from the tarfile. With two
arguments, FF, tar excludes all directories named SCCS and
RCS, all files with .o as their suffix, and all files named
errs, core, and a.out. The SYSV3 environment variable
overrides the default behavior. (See ENVIRONMENT section
below.) |
| h |
Follow symbolic links as if they were normal
files or directories. Normally, tar does not follow symbolic
links. |
| i |
Ignore directory checksum errors. |
| -j, --bzip2 |
filter archive through bzip2, use to decompress
.bz2 files. WARNING: some previous versions of tar used option
-I to filter through bzip2. When writing scripts, use --bzip2
instead of -j so that both older and newer tar versions will
work. |
| k size |
Requires tar to use the size argument as the
size of an archive in kilobytes. This is useful when the
archive is intended for a fixed size device such as floppy
disks. Large files are then split across volumes if they do
not fit in the specified size. |
| l |
Link. Output error message if unable to resolve
all links to the files being archived. If l is not specified,
no error messages are printed. |
| m |
Modify. The modification time of the file is
the time of extraction. This function modifier is
valid
only with the x function. |
| n |
The file being read is a non-tape device.
Reading of the archive is faster since tar can randomly seek
around the archive. |
| o |
Ownership. Assign to extracted files the user
and group identifiers of the user running the program, rather
than those on tarfile. This is the default behavior for users
other than root. If the o function modifier is not set and the
user is root, the extracted files will take on the group and
user identifiers of the files on tarfile (see chown
for more information). The o function modifier is only valid
with the x function. |
| p |
Restore the named files to their original
modes, and ACLs if applicable, ignoring the present umask.
This is the default behavior if invoked as super-user with the
x function letter specified. If super-user, SETUID and sticky
information are also extracted, and files are restored with
their original owners and permissions, rather than owned by
root. When this function modifier is used with the c function,
ACLs are created in the tarfile along with other information.
Errors will occur when a tarfile with ACLs is extracted
by
previous versions of tar . |
| P |
Suppress the addition of a trailing "/" on
directory entries in the archive. |
| q |
Stop after extracting the first occurrence of
the named file. tar will normally continue reading the archive
after finding an occurrence of a file. |
| v |
Verbose. Output the name of each file preceded
by the function letter. With the t function, v provides
additional information about the tarfile entries. The listing
is similar to the format produced by the -l option of the
ls
command. |
| w |
What. Output the action to be taken and the
name of the file, then await the user's confirmation. If the
response is affirmative, the action is performed; otherwise,
the action is not performed. This function modifier cannot be
used with the t function. |
| X |
Exclude. Use the exclude-file argument as a
file containing a list of relative path names for files (or
directories) to be excluded from the tarfile when using the
functions c, x, or t. Be careful of trailing white spaces.
Also beware of leading white spaces, since, for each line in
the excluded file, the entire line (apart from the newline)
will be used to match against the initial string of files to
exclude. Multiple X arguments may be used, with one
exclude-file per argument. In the case where included files
(see -I include-file option) are also specified, the excluded
files take precedence over all included files. If a file is
specified in both the exclude-file and the include-file (or on
the command line), it will be excluded. |
| [0-7] |
Select an alternative drive on which the tape
is mounted. The default entries are specified in
/etc/default/tar. If no digit or f function modifier is
specified, the entry in /etc/default/tar with digit "0" is the
default. |
| -I include-file |
Opens include-file containing a list of files,
one per line, and treats it as if each file appeared
separately on the command line. Be careful of trailing white
spaces. Also beware of leading white spaces, since, for each
line in the included file, the entire line (apart from the
newline) will be used to match against the initial string of
files to include. In the case where excluded files (see X
function modifier) are also specified, they take precedence
over all included files. If a file is specified in both the
exclude-file and the include-file (or on the command line), it
will be excluded. |
Remainder Syntax
| -C directory file |
Performs a chdir (see cd(1)) operation on
directory and performs the c (create) or r (replace) operation
on file . Use short relative path names for file . If file is
`.', archive all files in directory. This option enables
archiving files from multiple directories not related by a
close common parent. |
| file |
A path name of a regular file or directory to
be archived (when the c, r or u functions are specified),
extracted (x) or listed (t). When file is the path name of a
directory, the action applies to all of the files and
(recursively) subdirectories of that directory.
When a file is archived, and the E flag (see Function
Modifiers) is not specified, the filename cannot exceed 256
characters. In addition, it must be possible to split the name
between parent directory names so that the prefix is no longer
than 155 characters and the name is no longer than 100
characters. If E is specified, a name of up to PATH_MAX
characters may be specified.
For example, a file whose basename is longer than 100
characters could not be archived without using the E flag. A
file whose directory portion is 200 characters and whose
basename is 50 characters could be archived (without using E)
if a slash appears in the directory name somewhere in
character positions 151-156. |
Examples
Note: A ".tar" file is not a compressed files, it is
actually a collection of files within a single file uncompressed. If
the file is a .tar.gz ("tarball")
or ".tgz" file it is a collection of files that is compressed. If
you are looking to compress a file you would create the tar file
then gzip
the file.
Creating a tar file:
tar -cvvf file.tar myfile.txt
In the above example the system would create a tar named
file.tar in the directory you currently are in. Wildcards
could also be used in this command, for example: tar -cvvf
file.tar *.txt would compress all txt files in the current
directory.
tar -cvvf home.tar home/
In the above example command the system would create a tar file
named home.tar in the directory you currently are in of the home
directory.
Extracting the files from a tar file:
tar -xvvf myfile.tar
In the above example command the system would uncompress
(untar) the myfile.tar file in the current directory.
tar -xvvzf myfile.tar.gz
In the above example command the system would uncompress
(untar) the myfile.tar.gz file in the current directory.
Note: There is no "untar" linux / unix
command.
Creating a tarred file that is compressed with bzip
tar -cjvf test.tbz home/
Adding the j option to the tar command enables tar to compress
files and/or directories using bzip. In the above example the home
directory and all its subdirectories are added to the compressed
test.tbz file.
Related commands
ar
basename
cd
chown
cpio
csh
dirname
ls
mt
pack
pax
setfacl
umask
zcat
|
