Wikipedia:Reference desk/Archives/Computing/2017 December 13

Welcome to the Wikipedia Computing Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

December 13

Regex for Linux ifconfig

ipa=$(ifconfig | grep -Po "inet addr:\K[0-9]?[0-9]?[0-9]?\.[0-9]?[0-9]?[0-9]?\.[0-9]?[0-9]?[0-9]?\.[0-9]?[0-9]?[0-9]?")

This brings both external IP and internal (loopback) IP. Why does the loopback being brought as well? I can use another grep to remove it, but I'd prefer not to, if I have the option. ClinicalCosmologist (talk) 08:06, 13 December 2017 (UTC)

• The question seems to complain that the regexp matches the loopback IP (which I assume to be 127.0.0.1), but I fail to see why one would expect it not to be matched. By the way, for the IP matching part, it does not matter a whole lot since only "safe" inputs should be given, but the regexp looks awful - I have not tested either but you could shorten it to [0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3}.[0-9]{1,3} (arguably easier to parse, and avoids matching empty strings for numbers e.g. 8.8..1 is a match of the current), or at least correct the first digit of each to [0-2]?[0-9]?[0-9]?\.[0-2]?[0-9]?[0-9]?\.[0-2]?[0-9]?[0-9]?\.[0-2]?[0-9]?[0-9]? since the IPv4 numbers go from 0 to 255.

I would assume the real question is why does ifconfig return the loopback address. (And the real real question is how to avoid it.) Tigraan^{Click here to contact me} 09:20, 13 December 2017 (UTC)

Thank you for this information, I've learned from that and have implemented the shorter version, it brings the IP just fine. I also added grep -Po -m1 to make sure to stop in the first match, which is the external IP. I need for a small Bash script, I prefer to avoid giving further details. Again thank you dearly for your help. ClinicalCosmologist (talk) 10:37, 13 December 2017 (UTC)

In the shorter version posted by Tigraan above, you should escape the dots, as you did in your original version, since an unescaped dot will match any character. Also, by using -m1, you are relying on ifconfig printing the external IP address first. If it happens to print the loopback address first, this won't work. It would be safer to use something like grep -Po 'inet addr:\K\d{1,3}\.\d{1,3}\.\d{1,3}.\d{1,3}' | grep -v '127\.0\.0\.1' And of course if there are multiple external addresses, all of these solutions will fail, but without knowing more about what you are doing I can't comment on how you should handle that. CodeTalker (talk) 16:02, 13 December 2017 (UTC)

Duh! Yes, of course, the dots should be escaped. (How did I even fail to do that when the exemple given did it correctly?) Tigraan^{Click here to contact me} 17:15, 13 December 2017 (UTC)

Use Microsoft Word 'manage sources' feature to automate Chicago footnotes

Hi, I'm writing a paper using Chicago style footnotes. How do I use the 'manage sources' feature to automate these? As far as I can tell, the Chicago option there will only do bracketed citations, not footnotes... Amisom (talk) 17:56, 13 December 2017 (UTC)

Bing and Google Problems?

After today's Windows 10 update, I can't seem to connect to either Google or Bing. Other websites are fine. All I get is

This site can’t provide a secure connection

www.bing.com uses an unsupported protocol.
ERR_SSL_VERSION_OR_CIPHER_MISMATCH
HIDE DETAILS
Unsupported protocol
The client and server don't support a common SSL protocol version or cipher suite.

Rojomoke (talk) 23:40, 13 December 2017 (UTC)

Resolved

A reboot and a reinstall of my anti-virus seems to have fixed things. Rojomoke (talk) 19:34, 14 December 2017 (UTC)