Comment 11 for bug 573436

The following worked for me:

cd /etc/php5/cli/conf.d
sudo perl -pi.bk -e 's/(\s*)#/\1;/' *ini
sudo mkdir bk
sudo mv *.bk bk

Which only catches comments at the start of a line; also, backups of the original files are in the /etc/php5/cli/conf.d/bk directory.