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Saturday, April 20, 2013

Regexp Groups in Python

Let say that we have a string consist from a numeric continent code  (i.e. 1 for Europe) , followed by a country code  (i.e. 44 for UK)  and ended with a region code made in similar manner (i.e. Cambridge equal 65). A continent and a country are preceded with the letter C and a location with the letter L.

So we have the string C1C44L65 and we need to know the continent, counter and region codes, but numbers might have different length (i.e. 5, but also 55 or 555) so we cannot just grab selected characters from a string, but in Python we can use following regular expression to save all that information into "groups" for further use, in example in an mathematical operations (as integers).

info ="^C(?P[^\d]+)C(?P\d+)L(?P\d+)$", full_id)
continent = int("continent"))
country = int("country"))
region = int("region"))

Friday, April 19, 2013

Ubuntu and mix of NFS, NIS and autofs in post from past

Some time ago I had a problem with autofs, NIS and NFS during Ubuntu start. As far as I remember autofs was responsible for serving users home directories, define with NIS and  provided from remote location with  NFS. The problem that autofs started before network and NIS, so home directories weren't ready.

When I started look into the problem found that small change to autofs.conf should resolve the situation. I didn't deploy the fix on big scale (I were using CRUX on my desktop), but saved the patch to blogger and today finally found some time to share it. Maybe it will be useful for anyone.

root@test-upstart:/etc/init# diff -u autofs.conf ~wawrzekn/autofs.conf
--- autofs.conf2010-08-17 11:34:47.000000000 +0100 
+++ /home/wawrzekn/autofs.conf2011-02-06 12:19:48.678663000 +0000 
@@ -10,6 +10,15 @@ 
 pre-start script 
+while : 
+if [ $? = 0 ]  
+sleep 4 
 if [ -f /etc/default/autofs ]; then 
 . /etc/default/autofs