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Accepted
George Tasioulis
Asked: 2012-08-20 00:15:53 +0800 CST

sed replace text - escape characters

  • 772

I have a mysqldump file in which I want to replace the following text <a href="/tag/ with <a href="http://www.mydomain.com/tag/ but can't find a way to correctly escape all special characters.

I'm using the following command (+ a few other variants)
cat wordpress_posts.sql | sed 's%/<a href="\/\tag\/\/<a href="\http:/\/\www.mydomain.com/\tag/\/%g' > wordpress_posts_new.sql
but it's not working.

Can anybody help?

Update 1: Turns out that the source string in the mysqldump isn't <a href="/tag/ but <a href=\"/tag/ (note the extra backslash after the equal symbol)
Here's a pastebin of one line of the SQL file which contains the string I want to replace: http://pastebin.com/8G5mcxpJ

I tried all 3 suggested versions of the sed command, but none would replace the above string with <a href=\"http://www.mydomain.com/tag/ (yes I added the backslash after the equal symbol)

linux

3 Answers

  1. You don't have to escape /, you can just use any other delimiter:

    sed 's#<a href=\\"/tag/#<a href="http://www.mydomain.com/tag/#' wordpress_posts.sql
    • 6
  2. Best Answer

    No need to pipe cat to sed:

    $ sed 's/<a href="\/tag\//<a href="http:\/\/www.mydomain.com\/tag\//g' wordpress_posts.sql

    • Remove the percentage sign
    • You only need to escape the slash
    • Specify an in-place editing (-i) if you want
    • 4 
  3. $ cat wordpress_posts.sql | sed 's/\/tag\//http:\/\/www.mydomain.com\/tag\//' > wordpress_posts.sql
    • 3