md5sum for files in the directory

Here is nice one line solution to generate list of md5sums:
ls *.py | while read f;do md5sum $f;done > /tmp/list1.md5sums

Or oneliner for subdirectory tree:
find . -name "*.py" | while read f;do md5sum $f;done

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Charter 6rd configuration

It’s good to know, that Internet Service Provider CHARTER is getting ready for IPv6. There is a trial program, and here is working Linux configuration:

#edit /etc/config/network
#/etc/init.d/network reload
config interface 'wan6'
        option proto '6rd'
        option peeraddr ''
        option ip6prefix '2602:100::'
        option ip6prefixlen '32'
        option ip4prefixlen '0'

With this configuration it’s possible to browse websites like,,,,, and more, or to ping IPv6 addresses below.

#charter dns6 1
$ ping6 2607:f428:ffff:ffff::1
PING 2607:f428:ffff:ffff::1 (2607:f428:ffff:ffff::1): 56 data bytes
64 bytes from 2607:f428:ffff:ffff::1: seq=0 ttl=59 time=35.329 ms
64 bytes from 2607:f428:ffff:ffff::1: seq=1 ttl=59 time=40.211 ms
64 bytes from 2607:f428:ffff:ffff::1: seq=2 ttl=59 time=38.683 ms

$ ping6
PING (2001:4810::110): 56 data bytes
64 bytes from 2001:4810::110: seq=0 ttl=56 time=109.845 ms
64 bytes from 2001:4810::110: seq=1 ttl=56 time=63.858 ms

$ ping6
PING (2001:718:1:a100::161:30): 56 data bytes
64 bytes from 2001:718:1:a100::161:30: seq=0 ttl=50 time=148.320 ms

$ ping6
PING (2001:718:1:101::6): 56 data bytes
64 bytes from 2001:718:1:101::6: seq=0 ttl=50 time=149.869 ms

#google public DNS6
$ ping6 2001:4860:4860::8888
PING 2001:4860:4860::8888 (2001:4860:4860::8888): 56 data bytes
64 bytes from 2001:4860:4860::8888: seq=0 ttl=54 time=52.621 ms

$ ping6 2001:4860:4860::8844
PING 2001:4860:4860::8844 (2001:4860:4860::8844): 56 data bytes
64 bytes from 2001:4860:4860::8844: seq=0 ttl=54 time=57.752 ms
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Ethernet cables

With improving internet infrastructure, higher speeds are now possible. In case of gigabits per second speed one needs to pay attention to the ethernet cable. Better to choose Cat 5e or even Cat 6. There is nice article What Kind of Ethernet (Cat-5/e/6/a) Cable Should I Use?
Wikipedia: CAT 5, CAT 6

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SSH port tunneling

Let’s say, a user1 has a ssh connection to the, and he would like to view a webpage on intranet server available from exampleserver.
Then command could be like this:

ssh -L 8000:

If using Putty, one would have to do add at Connections/SSH/Tunnels (source port 8000, destination


Now user1 can see the webpage in browser at localhost:8000 .

There are nice articles covering this topic, like SSH Tunnel – Local and Remote Port Forwarding Explained with Examples, or SSH Port Tunneling with Putty.

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One gigasecond is:
1,000,000,000 seconds
11574.074 days (1 day is 84,600 seconds)
31.688738506811430964562103462971 gregorian years (365.2425 days)

2 Gs = 63.377477013622861929124206925941 gregorian years
3 Gs = 95.066215520434292893686310388913 gregorian years
4 Gs = 126.75495402724572385824841385188 gregorian years

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Institute for the Future

The Institute for the Future is is a 501(c)3 nonprofit corporation founded in 1968 by a group of former RAND Corporation researchers with a grant from the Ford Foundation to take leading-edge research methodologies into the public and business sectors.
Silicon Valley based IFTF is a source of interesting ideas and information mentioned often in the news.

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Remote desktop over VPN

Having work on Windows Remote Desktop over VPN and cell phone network, it was an opportunity to check how much bandwidth one could use. Probably it would depend how many screen is user flipping through, but answer is about 1 MB per minute. It means 1 GB cellular data would provide about 1000 minutes or 16.6 hours. One could imagine more effective way how to use data, but it’s different story.

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RESTfull web

REST is acronym for Representational state transfer. It was defined in 2000 by Roy Fielding in his doctoral dissertation. System conforming REST constraints can be called RESTful and most the time is using protocol HTTP utilizing its methods GET, POST, PUT, DELETE, and sometimes more. Web service APIs that adhere to the REST architectural constraints are called RESTful APIs.

Architectural constraints:

  1. Client–server
  2. Stateless
  3. Cacheable
  4. Layered system
  5. Code on demand -optional (applets)
  6. Uniform interface
    Identification of resources (URI)
    Manipulation of resources through representations (JSON, XML, HTML, text, …)
    Self-descriptive messages (application/json, text/html, … )
    Hypermedia as the engine of application state (HATEOAS)


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Typescript in jEdit

Java based editor jEdit allows to syntax highlight plethora of languages and their file extensions. Adding typescript highlighting can be as simple as exiting file jEdit/modes/catalog.
One can take advantage of the fact, that the typescript is an extension of the javascript, so .ts extension can be added. There is also .ts extension already for typoscript, so it needs to be disabled:

<MODE NAME="javascript"		FILE="javascript.xml"
				FILE_NAME_GLOB="{*.{js,ts},Buildsub}" />

<MODE NAME="typoscript"		FILE="typoscript.xml"

Better way would be to develop specific typescript.xml, which would allow to add new features.

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Borrelia mayonii

More to worry about ticks in Minnesota, as The New York Times reports about new species spreading Lyme diseases: Borrelia mayonii, discovered at Mayo Clinic, Rochester MN.
Borrelia mayonii in a laboratory dish
Borrelia mayonii in a laboratory dish.
Credit: Mayo Foundation for Medical Education and Research.

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