GNU Tar Tips

GNU tar has several interesting additional features like:

• -d, --diff, --compare find differences between archive and file system

• -p, --same-permissions, --preserve-permissions extract all protection information
• -P, --absolute-names don't strip leading '/'s from file names
• -C - switch to particular directory before the start of the operation.

To list the contents of a tarball without extracting files, use the t option as shown below. You do need option -f  to specify the tarball. Omitting it is a very frequent mistake; in this case tar just wait forever input from stdin.  Including the v option as well results in a long listing.

tar tf myfiles.tar

tar tvf myfiles.tar

Viewing files from the tarball

To extract to standard output a file from archive you can use -O or --to-stdout, for example

tar -xOf myfiles.tar hosts | more

However, ‘--to-command’ may be more convenient for use with multiple files.

Extraction of the tar archives

Archives created with tar include the file ownership, file permissions, and access and creation dates of the files. The p (preserve) option restores file permissions to the original state. This is usually good since you'll ordinarily want to preserve permissions as well as dates so that executables will execute and you can determine how old they are. In some situations, you might not like that original owners are retrieved, since the original owners may be people at some other organization altogether. The tar command will set up ownership according to the numeric UID of the original owner. If someone in your local passwd file or network information service has the same UID, that person will become the owner; otherwise the owner will display numerically. Obviously, ownership can be altered later.

tar xvpf myachive.tar

Extract each file from a shell prompt by typing tar xvzf file.tar.gz from the directory you saved the file.

You can extract to standard output (via option -O) and redirect it, for example

tar -xvOf etc_baseline110628_0900.tar  hosts > /etc/hosts110628

NEWS CONTENTS

• 20120911 : Tips and Tricks: Splitting tar archives on the fly by Alexander Todorov ( Tips and Tricks: Splitting tar archives on the fly, Sep 11, 2012 )
• 190730 : TAR tricks & tips by Viktor Balogh ( Viktor Balogh's HP-UX blog )

Old News ;-)

[Sep 11, 2012] Tips and Tricks: Splitting tar archives on the fly by Alexander Todorov

Splitting big files into pieces is a common task. Another common task is to create a tar archive, and split it into smaller chunks that can be burned onto CD/DVD. The straightforward approach is to create the archive and then use 'split.' To do this, you will need more free space on your disk. In fact, you'll need space twice the size of the created archive. To avoid this limitation, split the archive as it is being created.

To create a tar archive that splits itself on the fly use the following set of commands:

First create the archive:

tar -czf /dev/stdout $(DIRECTORY_OR_FILE_TO_COMPRESS) | split -d -b $(CHUNK_SIZE_IN_BYTES) - $(FILE_NAME_PREFIX)

To extract the contents:

cat $(FILE_NAME_PREFIX)* >> /dev/stdout | tar -xzf /dev/stdin

The above shown set of commands works on the fly. You don't need additional free space for temporary files.

A few notes about this exercise:

• 'tar -L' prompts you on every chunk created. Compression can not be used with -L option. The above command is not interactive and does not prompt for anything. Compression can be used.
• The number of separate files is 100. This is because we use numerical suffixes – 'split -d.' If the specified chunk size is small you will get 'split: Output file suffixes exhausted' error. Try with bigger chunk size or with alphabetic suffixes.
• 'cat' will concatenate the files properly if they are not renamed. This is due to the fact that the sort order is retained by the appended chunk suffixes.
• Replace 'tar -z' with 'tar -j' for bzip2 compression or try your favourite compression program. Almost all 'tar' and 'split' options should be possible.
• The resulting chunk files are not valid tar archives. They can not be extracted separately. If you want such functionality use 'split-tar,' which also needs more free space.

The information provided in this article is for your information only. The origin of this information may be internal or external to Red Hat. While Red Hat attempts to verify the validity of this information before it is posted, Red Hat makes no express or implied claims to its validity.

vsego:

Isn't it easier to just omit the "f"?
tar cz $(DIRECTORY_OR_FILE_TO_COMPRESS) | split -d -b $(CHUNK_SIZE_IN_BYTES) – $(FILE_NAME_PREFIX)
cat $(FILE_NAME_PREFIX)* | tar xz

Alexander Todorov:

You are right. Using /dev/stdin and /dev/stdout is to be more clear.

1. Klaus Lichtenwalder says:
   December 14th, 2007 at 2:49 pm

   Just a few nitbits… If you want to use stdin/stdout with tar, it's simply a -
   e.g.: tar cf – . | (cd /elsewhere; tar xf -)

   cat always appends its arguments to stdout, so
   cat $(prefix)* | command
   is sufficient. I don't know and (honestly) don't care if gnu-tar sends its output to stdout if no f argument given, every other unix uses the default tape device (which is /dev/rmt) if no f argument given (I have to work with Solaris and AIX too…).

TAR tricks & tips by Viktor Balogh

Viktor Balogh's HP-UX blog

This is how to tar a bunch of files and send it over network to another machine over SSH, in one turn:

# cd /etc; tar cf - passwd | ssh hp01a01.w1 "cd /root;tar xf - passwd"

Note that with tar you must always use relative path, anyway the files on the target system will be extracted with fullpath and the original files will be overwritten. GNU tar also offers some options which allow the user to modify/transform the paths when files are extracted. You can find the GNU tar on HP-UX under the name gtar, you can download it from the HP-UX porting center:

# which gtar
/usr/local/bin/gtar

If you have a 'tar' archive that was made with absolute paths, use 'pax' to extract it to a different directory:

# pax -r -s '|/tmp/|/opt/|' -f test.tar

If you unpack this archive with other user privileges (non-root) all uid and gid will be replaced with the uid and gid from this user. Keep that in mind, if you make backups/restore, practically always do any backup/restore with UID 0.

The use of tar with find isn't apt to work if there are lots of files. Instead use pax(1):

# find . -atime +7 | pax -w | gzip > backup.tgz

Recommended Links

Softpanorama Recommended

Top articles

Sites

Etc

Society

Groupthink : Two Party System as Polyarchy : Corruption of Regulators : Bureaucracies : Understanding Micromanagers and Control Freaks : Toxic Managers :   Harvard Mafia : Diplomatic Communication : Surviving a Bad Performance Review : Insufficient Retirement Funds as Immanent Problem of Neoliberal Regime : PseudoScience : Who Rules America : Neoliberalism  : The Iron Law of Oligarchy : Libertarian Philosophy

Quotes

War and Peace : Skeptical Finance : John Kenneth Galbraith :Talleyrand : Oscar Wilde : Otto Von Bismarck : Keynes : George Carlin : Skeptics : Propaganda  : SE quotes : Language Design and Programming Quotes : Random IT-related quotes :  Somerset Maugham : Marcus Aurelius : Kurt Vonnegut : Eric Hoffer : Winston Churchill : Napoleon Bonaparte : Ambrose Bierce :  Bernard Shaw : Mark Twain Quotes

Bulletin:

Vol 25, No.12 (December, 2013) Rational Fools vs. Efficient Crooks The efficient markets hypothesis : Political Skeptic Bulletin, 2013 : Unemployment Bulletin, 2010 :  Vol 23, No.10 (October, 2011) An observation about corporate security departments : Slightly Skeptical Euromaydan Chronicles, June 2014 : Greenspan legacy bulletin, 2008 : Vol 25, No.10 (October, 2013) Cryptolocker Trojan (Win32/Crilock.A) : Vol 25, No.08 (August, 2013) Cloud providers as intelligence collection hubs : Financial Humor Bulletin, 2010 : Inequality Bulletin, 2009 : Financial Humor Bulletin, 2008 : Copyleft Problems Bulletin, 2004 : Financial Humor Bulletin, 2011 : Energy Bulletin, 2010 : Malware Protection Bulletin, 2010 : Vol 26, No.1 (January, 2013) Object-Oriented Cult : Political Skeptic Bulletin, 2011 : Vol 23, No.11 (November, 2011) Softpanorama classification of sysadmin horror stories : Vol 25, No.05 (May, 2013) Corporate bullshit as a communication method  : Vol 25, No.06 (June, 2013) A Note on the Relationship of Brooks Law and Conway Law

History:

Fifty glorious years (1950-2000): the triumph of the US computer engineering : Donald Knuth : TAoCP and its Influence of Computer Science : Richard Stallman : Linus Torvalds  : Larry Wall  : John K. Ousterhout : CTSS : Multix OS Unix History : Unix shell history : VI editor : History of pipes concept : Solaris : MS DOS :  Programming Languages History : PL/1 : Simula 67 : C : History of GCC development :  Scripting Languages : Perl history   : OS History : Mail : DNS : SSH : CPU Instruction Sets : SPARC systems 1987-2006 : Norton Commander : Norton Utilities : Norton Ghost : Frontpage history : Malware Defense History : GNU Screen : OSS early history

Classic books:

The Peter Principle : Parkinson Law : 1984 : The Mythical Man-Month :  How to Solve It by George Polya : The Art of Computer Programming : The Elements of Programming Style : The Unix Hater’s Handbook : The Jargon file : The True Believer : Programming Pearls : The Good Soldier Svejk : The Power Elite

Most popular humor pages:

Manifest of the Softpanorama IT Slacker Society : Ten Commandments of the IT Slackers Society : Computer Humor Collection : BSD Logo Story : The Cuckoo's Egg : IT Slang : C++ Humor : ARE YOU A BBS ADDICT? : The Perl Purity Test : Object oriented programmers of all nations : Financial Humor : Financial Humor Bulletin, 2008 : Financial Humor Bulletin, 2010 : The Most Comprehensive Collection of Editor-related Humor : Programming Language Humor : Goldman Sachs related humor : Greenspan humor : C Humor : Scripting Humor : Real Programmers Humor : Web Humor : GPL-related Humor : OFM Humor : Politically Incorrect Humor : IDS Humor : "Linux Sucks" Humor : Russian Musical Humor : Best Russian Programmer Humor : Microsoft plans to buy Catholic Church : Richard Stallman Related Humor : Admin Humor : Perl-related Humor : Linus Torvalds Related humor : PseudoScience Related Humor : Networking Humor : Shell Humor : Financial Humor Bulletin, 2011 : Financial Humor Bulletin, 2012 : Financial Humor Bulletin, 2013 : Java Humor : Software Engineering Humor : Sun Solaris Related Humor : Education Humor : IBM Humor : Assembler-related Humor : VIM Humor : Computer Viruses Humor : Bright tomorrow is rescheduled to a day after tomorrow : Classic Computer Humor

The Last but not Least Technology is dominated by two types of people: those who understand what they do not manage and those who manage what they do not understand ~Archibald Putt. Ph.D

The statements, views and opinions presented on this web page are those of the author (or referenced source) and are not endorsed by, nor do they necessarily reflect, the opinions of the Softpanorama society. We do not warrant the correctness of the information provided or its fitness for any purpose. The site uses AdSense so you need to be aware of Google privacy policy. You you do not want to be tracked by Google please disable Javascript for this site. This site is perfectly usable without Javascript.

Last modified: July 29, 2019