add debian repository with sed command

Question

I would like to auto generate my debian system virtualbox with provisionning. I must install don't standard or default PHP environment. I must add repository dotdeb for find special package PHP for 5.3 version.

My shell provisionning script must edit /etc/apt/sources.list for adding line corresponding to dotdeb repository. This line are :

deb http://packages.dotdeb.org wheezy all
deb-src http://packages.dotdeb.org wheezy all

How can edit my file with sed command for result this :

#

# deb cdrom:[Debian GNU/Linux 7.11.0 _Wheezy_ - Official amd64 NETINST Binary-1 20160605-17:36]/ wheezy main

#deb cdrom:[Debian GNU/Linux 7.11.0 _Wheezy_ - Official amd64 NETINST Binary-1 20160605-17:36]/ wheezy main

deb http://httpredir.debian.org/debian wheezy main
deb-src http://httpredir.debian.org/debian wheezy main

deb http://security.debian.org/ wheezy/updates main
deb-src http://security.debian.org/ wheezy/updates main

deb http://packages.dotdeb.org wheezy all
deb-src http://packages.dotdeb.org wheezy all

The default content file of /etc/apt/sources.list is :

#

# deb cdrom:[Debian GNU/Linux 7.11.0 _Wheezy_ - Official amd64 NETINST Binary-1 20160605-17:36]/ wheezy main

#deb cdrom:[Debian GNU/Linux 7.11.0 _Wheezy_ - Official amd64 NETINST Binary-1 20160605-17:36]/ wheezy main

deb http://httpredir.debian.org/debian wheezy main
deb-src http://httpredir.debian.org/debian wheezy main

deb http://security.debian.org/ wheezy/updates main
deb-src http://security.debian.org/ wheezy/updates main

Finally, I just want to add a empty line at the end of file and after add to specific line. But I don't find how add empty line at the end of file and add specific line with multi special character with sed command...

Answer 1

sed -i '$ a\\ndeb http://packages.dotdeb.org wheezy all\ndeb-src http://packages.dotdeb.org wheezy all' /etc/apt/sources.list

Answer 2

If you simply want to add a new line at last of Input_file do following.

echo "" >> Input_file