Technology DB

Here are some cool python one liners.

• Parse apache log using python: print 5th field
  python -c “import csv,sys;f=csv.reader(sys.stdin, delimiter=’ ‘); print ‘\n’.join([r[5] for r in f])
• Generate frequency histogram from a text files of terms
  cat file.txt | sort | uniq -c | sort -rn
• print 2nd column of a tab separated file
  awk -F”\t” ‘{print $2}’
• perl search replace from files
  perl -i -p -e ’s/old/new/g’

These are some quick apache tips to improve the performance of your web site:

1. compress your html/css/js content by making these changes to your httpd.conf
   SetOutputFilter DEFLATE
   AddOutputFilterByType DEFLATE text/html text/css application/x-javascript

   To see it working, install livehttpheaders addon in firefox, open Tools->Live HTTP headers, and fetch http://www.technologydb.com/. In case some headers are missing, clear your firefox cache. Here are the screenshots:

   

   
   

2. cache images, css and js
   ExpiresByType text/css “access plus 240 hours”
   ExpiresByType image/jpeg “access plus 24 hours”
   ExpiresByType image/jpg “access plus 24 hours”
   ExpiresByType image/gif “access plus 24 hours”
   ExpiresByType application/x-javascript “access plus 24 hours”

   This will avoid browser making an http call to server for these content types.

3. Avoid using too many domain names. Each domain require a DNS lookup which is expensive.
4. Keep limited number of css and javascripts files. Browsers generally limit parallel number of fetches.

For a full list of advanced tips on website performance you can view this excellent page maintained by Yahoo Exceptional Performance (http://developer.yahoo.com/performance/)

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