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Every new command is wrapped in a tweet and posted to Twitter. Following the stream is a great way of staying abreast of the latest commands. For the more discerning, there are Twitter accounts for commands that get a minimum of 3 and 10 votes - that way only the great commands get tweeted.
Use your favourite RSS aggregator to stay in touch with the latest commands. There are feeds mirroring the 3 Twitter streams as well as for virtually every other subset (users, tags, functions,…):
Subscribe to the feed for:
Leave it to a proprietary software vendor to turn a cheap and easy parlor trick into a selling point. "Hey guys, why don't we turn our _collection of multiple files_ into a *collection of multiple files*!!" Extract the ^above with this:
cat pics.tar.gz.??? | tar xzv
^extract on any Unix - no need to install junkware!
(If you must make proprietary software, at least make it do something *new*)
if [ -e windows ]; then use 7-Zip
create an archive of files with access time older than 5 days, and remove original files.
This will update the tarball, adding files that have changed since the last update.
This assumes that the tarball is in the same directory as the files being archived.
N.B. This command can't be used on compressed tarballs.
N.B. This will add the updated files to the tarball, so that the tarball will have two versions of each file. This will make the tarball larger, but doesn't have any other significant effect.
Where foodir is the directory you want to zip up.
PRIVATEKEY - Of course the full path to the private key \n
HOST - The host where to get the backup \n
SOURCE - The directory you wish to backup \n
DESTINATION - The destination for the backup on your local machine
gpg's compression is as suitable as gzip's however your backups can now be encrypted.
to extract use:
gpg < folder.tpg | tar -xf -
An easy one but nice to keep in mind.
Clone a partion with tar.
creates a tar.gz with a name like:
of a given directory.
this file was made 10 April 2009 at 5:30:53pm
see date's man page to customize the timestamp format
This command will copy files and directories from a remote machine to the local one.
Ensure you are in the local directory you want to populate with the remote files before running the command.
To copy a directory and it's contents, you could:
ssh user@host "(cd /path/to/a/directory ; tar cvf - ./targetdir)" | tar xvf -
This is especially useful on *nix'es that don't have 'scp' installed by default.
This is useful for sending data between 2 computers that you have shell access to. Uses tar compression during transfer. Files are compressed & uncompressed automatically. Note the trailing dash on the listening side that makes netcat listen to stdin for data.
on the listening side:
sudo nc -lp 2022 | sudo tar -xvf -
explanation: open netcat to -l listen on -p port 2022, take the data stream and pipe to tar -x extract, -v verbose, -f using file filename - means "stdin"
on the sending side:
tar -cvzf - ./*| nc -w 3 name_of_listening_host 2022
explanation: compress all files in current dir using tar -c create, -v verbose, -f using file, - filename - here means "stdout" because we're tar -c instead of tar -x, -w3 wait 3 seconds on stream termination and then end the connection to the listening host name_of_listening_host, on port 2022
I recently found myself with a filesystem I couldn't write to and a bunch of files I had to get the hell out of dodge, preferably not one at a time. This command makes it possible to pack a bunch of files into a single archive and write it to a remote server.
Create backup (.tar.gz) for all first-level directory from current dir.
create tar.bz2 package from files "-type f" modificated today "-mtime -1" in ~/project
Add z to the flags to enable compression.
* Adjust the find command to your own filters.
* The -P flag forces to keep absolute paths in the tarball, so that you can be sure that the exact same file hierarchy will be created on the second machine.
These days, most software distributed in tar files will just contain a directory at the top level, but some tar files don't have this and can leave you with a mess of files in the current folder if you blindly execute
tar zxvf something.tar.gz
This command can help you clean up after such a mistake. However, note that this has the potential to do bad things if someone has been *really* nasty with filenames.
You can exclude more system folders or individual files which are not necessary for the backup and can be recreated after the restore procedure, like /lost+found, /mnt, /media, /tmp, /usr ...
Restoring the above backup procedure is as simple as becoming root and typing:
tar zxpf backup.tgz -C /
You can extract any file or directory out of the backup.tgz file for recovery, for instance, if you have a corrupt or mis-configured fstab file, you could simply issue the command:
tar zxpf backup.tgz /ect/fstab -C /
v add verbose option to see files processed
A far safer solution is to restore the desired files under a different directory, and then compare, move, or update the files to their original locations afterward.
This command tar?s up a directory and sends the output to gzip, showing a rate of 223MB/s.
This may require you installing the pv command.
For debian based users out there:
sudo aptitude install pv