netcat tar backup

debian netcat-openbsd is leaner, cleaner & more efficient than debian netcat-traditional. if you get a choice, prefer the openbsd version.

i now use busybox wherever i can, including nc and tar. small, simple, clean, standard, available the same everywhere.

$ busybox nc

Usage: nc [-iN] [-wN] [-l] [-p PORT] [-f FILE|IPADDR PORT] [-e PROG]

Open a pipe to IP:PORT or FILE

-e PROG Run PROG after connect
-l      Listen mode, for inbound connects (use -l twice with -e for persistent server)
-p PORT Local port
-w SEC  Timeout for connect
-i SEC  Delay interval for lines sent
-f FILE Use file (ala /dev/ttyS0) instead of network

$ busybox tar

Usage: tar -[cxtZzJjahmvO] [-f TARFILE] [-C DIR] [FILE]...

Create, extract, or list files from a tar file

Operation:
        c       Create
        x       Extract
        t       List
        f       Name of TARFILE ('-' for stdin/out)
        C       Change to DIR before operation
        v       Verbose
        Z       (De)compress using compress
        z       (De)compress using gzip
        J       (De)compress using xz
        j       (De)compress using bzip2
        a       (De)compress using lzma
        O       Extract to stdout
        h       Follow symlinks
        m       Don't restore mtime

at {destination}:

$ nc -l -p {port} | tar xpv[z|j]f -

at {source}:

$ tar cpv[z|j]f - {directory} | nc {destination host/ip} {port}

[z|j] compression: use over slower networks. ignore for faster networks and/or slower computers.

tar streams much faster copying than scp 'ping-pong', especially when you have lots of files.

copy files from {some-server} to your machine:

$ ssh {some-server} ‘cd /some/dir && tar cz dir’ | tar xz

and the other direction:

$ tar cz dir | ssh {some-server} `cd /some/dir && tar xz`

image a disk across the network from {box1} to {box2}:

at {box2}:

$ nc -l {port} [-vv] | dd of={disk.img} bs=1M

at {box1}:

$ dd if=/dev/sda bs=1M | nc {box2 host/ip} {port} [-vv] -q 10

[-vv] use at the box1 (and/or box2, if fast enough)

restore this image in {box2} to {box3}:

at {box3}:

$ nc -l {port} [-vv] | dd of=/dev/sda bs=1M

at {box2}:

$ dd if={disk.img} bs=1M | nc {box1 host/ip} {port} [-vv]

compressed backup

at {box1}:

$ tar cpvJf - {directory} | nc {box2 host/ip} {port}

at {box2}:

$ nc -l -p {port} | dd of={directory}.tar.xz bs=1k

---

references:
http://nc110.sourceforge.net/
http://sans.org/security-resources/sec560/netcat_cheat_sheet_v1.pdf
http://wikipedia.org/wiki/netcat
http://saurorja.org/2012/04/06/network-file-transfer-using-netcat/
http://compsoc.dur.ac.uk/~djw/tarpipe.html

skype

http://wiki.debian.org/skype

skype's debian apt repository seems to have gone kaput! .deb intall packages give errors, due to missing dependencies. also noticed that the 64bit .deb wanted many 32bit dependencies. skype need to get their act together. losing confidence... only reason to use this is my friends using this. chicken-and-egg? you bet!

and the shambles started after microsoft took over skype. i can remember a time when skype client was lean clean & efficient. now it is humungous bloatware spyware crapware..

printing how-to

# apt-get install cups
# apt-get install cups-client
# apt-get install cups-pdf

check available ghostscript drivers
$ gs -h

http://localhost:631/

http://localhost:631/help/
http://cups.org/documentation.php/doc-other/cups-help.html

https://wiki.linuxfoundation.org/en/OpenPrinting/Database/CUPSDocumentation
http://wiki.debian.org/SystemPrinting