Category Archives: Linux

Raspberry Pi automates cable modem power cycling task

Intro I lose my Internet far too often – sometimes once a day. Of course I have lots of network gear in a rat’s nest of cables. I narrowed the problem down to the cable modem, which simply needs to … Continue reading

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Relative time with the linux date command

The situation A server in Europe needs to transfer a log file which is written every hour from a server in the US. The filename format is 20171013-1039.log.gz And we want the transfer to be done every hour. How we … Continue reading

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Fail2ban fails to work, I built my own

Intro I’ve sung the praises of fail2ban as a modern way to shutdown those annoying probes of your cloud server. I recently got to work with a Redhat v 7.4 system, so much newer than my old CentOS 6 server. … Continue reading

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Verifying a pkcs12 file with openssl

Intro The easy way How to examine a pkcs12 (pfx) file $ openssl pkcs12 ‐info ‐in file_name.pfx It will prompt you for the password a total of three times! The hard way I went through this whole exercise because I … Continue reading

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Compiling curl and openssl on Redhat Linux

Intro I have an ancient Redhat system which I’m not in a position to upgrade. I like to use curl to test web sites, but it’s getting to the point that my ancient version has no SSL versions in common … Continue reading

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Reverse upper and lower case letters

Intro I am a look-at-the-keyboard typist! I can’t count the number of times I’ve begun an email with CAPs lock on, and found a nice correspondence looking like this: hI aNDRES,   i RE-CREATED THE SCRIPT. … Tired of the … Continue reading

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curl showing its age with SSL error

Intro I’ve used curl as a debugging tool for a long time. But time moves on and my testing system didn’t. So now for the first time I saw an error that is produced by this situation, and I will … Continue reading

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Adding a swap file in Amazon AWS for CentOS

Intro I was running a new daemon on my server, factomd, to experiment with digital currency. It’s an old m1.small instance with only 1.7 GB of memory. The first few times I ran it it would 70000 or so blocks, … Continue reading

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Switch home router to DD-WRT: FAIL

Intro I am having problems with my home router, a Cisco E1200, especially with the wireless connections. I thought it might be interesting to try to run it using the open source routing code DD-WRT. Since I am a Linux … Continue reading

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Roll your own dynamic DNS update service

Intro I know my old Cisco router only has built-in support for two dynamic DNS services, dyndns.org and TZO.com. Nowadays you have to pay for those, if even they work (the web site domain names seem to have changed, but … Continue reading

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