Ansibleで設定ファイルの行を書き換える(コンテキスト編) ref: http://qiita.com/komeda-shinji/items/e24fab2ab0f2f5858111

file0.txt

- hosts: servers
  vars:
    httpd_conf: /etc/apache2/apache2.conf
  tasks:
    - name: lookup DocumentRoot in VirtualHost
      shell: sed -n '/^<VirtualHost \*:80>/,/<\/VirtualHost>/{/DocumentRoot/p; }' {{httpd_conf}}
      register: lookup
      changed_when: False
    - name: change httpd.conf
      shell: sed -i$(date +'.%Y-%m-%d@%H:%M~') '/^<VirtualHost \*:80>/,/<\/VirtualHost>/{s/\(DocumentRoot[[:space:]]*\).*$/\1\/var\/www/; }' {{httpd_conf}}
      when: lookup.stdout != ""