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Archive for the ‘UNIX’ Category

Find and replace across multile files, recursivly

March 12th, 2011 No comments

In a previous post, I gave a command for doing a find and replace operation across multiple files in a directory.

I have used that command a number of times over the years but the problem with it is that it only works if all of the files you want to change are in the same directory.

I sometimes have need to perform this find and replace operation across files in different directories.

For this, you can use the find command and use xargs to run sed:

find . -name '*.txt' -print0 | xargs -0 sed -i 's|originaltext|replacementtext|g'

This command will find any files with the .txt extension, in the current directory or any directory below it and run it through sed to replace ‘originaltext’ with ‘replacementtext’.

Categories: UNIX Tags: , ,

See a list of current connections to your web server

December 2nd, 2009 No comments

If you have a high load on your web server, it’s useful to be able to see a list of the current connections on port 80 as sometimes high load can be caused by someone abusing the site – for example scraping it or some kind of denial of service attack.

This code will show a list of the ip’s currently connected to your server on port 80 with a count of the number of connections to the left of it. It’s ordered by the number of connections – highest first:

netstat -ntulpa | grep :80 | awk '{print $5}' | cut -d: -f1 | sort -n | uniq -c | sort -n -r

Categories: UNIX Tags: , , ,

Find and Replace Across Multiple Files

March 15th, 2009 4 comments

Have you ever needed to change the same thing in a load of files and have had to sit there and go through each one in turn and make the same change?

This is a really useful and simple command:

perl -pi -w -e 's/from text/to text/g;' *

It simply goes through all files matching * and runs the regular expression, ‘s/from text/to text/g’ – which means replace all instances of “from text” with “to text”.  nifty!

Categories: UNIX Tags: , , ,