If you missed that argument when initially installing php5 and want to add it after the fact, this is all you need:
sudo apt-get install php5-readline
To use these functions you must compile the CGI or CLI version of PHP with readline support. You need to configure PHP --with-readline[=DIR] . If you want to use the libedit readline replacement, configure PHP --with-libedit[=DIR] .
If you missed that argument when initially installing php5 and want to add it after the fact, this is all you need:
sudo apt-get install php5-readline
Use dotdeb. It's like 1 minute work.
Follow https://www.dotdeb.org/instructions/
Do only points 1,3,4 (omit 2)
and then
sudo apt-get install php5-readline