Copy files over network using compression

on the listening side: sudo nc -lp 2022 | sudo tar -xvf - and on the sending side: tar -cvzf - ./*| nc -w 3 name_of_listening_host 2022
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

2009-03-27 09:59:33

These Might Interest You

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    ssh user@host "cd targetdir; tar cfp - *" | dd of=file.tar
    bwoodacre · 2009-03-18 07:43:22 3
  • Mirror a remote directory using some tricks to maximize network speed. lftp:: coolest file transfer tool ever -u: username and password (pwd is merely a placeholder if you have ~/.ssh/id_rsa) -e: execute internal lftp commands set sftp:connect-program: use some specific command instead of plain ssh ssh:: -a -x -T: disable useless things -c arcfour: use the most efficient cipher specification -o Compression=no: disable compression to save CPU mirror: copy remote dir subtree to local dir -v: be verbose (cool progress bar and speed meter, one for each file in parallel) -c: continue interrupted file transfers if possible --loop: repeat mirror until no differences found --use-pget-n=3: transfer each file with 3 independent parallel TCP connections -P 2: transfer 2 files in parallel (totalling 6 TCP connections) sftp://remotehost:22: use sftp protocol on port 22 (you can give any other port if appropriate) You can play with values for --use-pget-n and/or -P to achieve maximum speed depending on the particular network. If the files are compressible removing "-o Compression=n" can be beneficial. Better create an alias for the command. Show Sample Output

    lftp -u user,pwd -e "set sftp:connect-program 'ssh -a -x -T -c arcfour -o Compression=no'; mirror -v -c --loop --use-pget-n=3 -P 2 /remote/dir/ /local/dir/; quit" sftp://remotehost:22
    colemar · 2014-10-17 00:29:34 0
  • a - archive m5 - compression level, 0= lowest compression...1...2...3...4...5= max compression -v5M split the output file in 5 megabytes archives, change to 700 for a CD, or 4200 for a DVD R recursive for directories, do not use it for files It's better to have the output of a compression already split than use the 'split' command after compression, would consume the double amount of disk space. Found at

    rar a -m5 -v5M -R myarchive.rar /home/
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  • Adds high-performance, lightweight lz4 compression to speed the transfer of files over a trusted network link. Using (insecure) netcat results in a much faster transfer than using a ssh tunnel because of the lack of overhead. Also, LZ4 is as fast or faster than LZ0, much faster than gzip or LZMA, an in a worst-case scenario, incompressible data gets increased by 0.4% in size. Using LZMA or gzip compressors makes more sense in cases where the network link is the bottleneck, whereas LZ4 makes more sense if CPU time is more of a bottleneck.

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What Others Think

If you have scp on the client and the corresponding daemon on the server side, you can just use scp filename user@host:/target/directory
DNSpyder · 482 weeks ago
Curious why a sudo is needed in "sudo nc -lp 2022" (port 2022 is not a privileged port)?
mpb · 482 weeks ago
But where is the compression? You should pipe your data through bzip2, gzip whatever.
OJM · 482 weeks ago
@OJM Good catch - I left out the "-z" option that filters the archive through gzip. Post modified. @mpb I should have pointed out that port 2022 is arbitrary and was open for me when I needed this command. It could be replaced with whatever works for you though. @DNSpyder scp works, but the combination of netcat & tar is faster even with compression turned on in scp (-C).
smcpherson · 482 weeks ago
If you need encryption then use cryptcat:
OJM · 482 weeks ago
asmoore82 · 481 weeks and 2 days ago
This works in reverse, too, i.e. the listening side can be the "sender": # on the listening/sending side tar -cvzf - ./* | nc -v -l 2022 # on the receiving side nc -v -w3 name_of_listening_host 2022 | tar -xvf - The listening netcat will wait for the incoming connection before it starts sending the input piped from tar.
jordan · 283 weeks and 6 days ago

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

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