$re = '/(.+):.+\(.+\),/U';
$str = 'fakeroot:amd64 (1.20.2-1, automatic), libisl10:amd64 (0.12.2-2, automatic), libasan0:amd64 (4.8.4-1, automatic), libasan1:amd64 (4.9.2-10, au
tomatic), libquadmath0:amd64 (4.9.2-10, automatic), libmpc3:amd64 (1.0.2-1, automatic), make:amd64 (4.0-8.1, automatic), libfile-fcntllock-perl:amd64
(0.22-1+b1, automatic), linux-kbuild-3.16:amd64 (3.16-3, automatic), libubsan0:amd64 (4.9.2-10, automatic), cpp-4.8:amd64 (4.8.4-1, automatic), cpp-4.
9:amd64 (4.9.2-10, automatic), libstdc++-4.9-dev:amd64 (4.9.2-10, automatic), libgomp1:amd64 (4.9.2-10, automatic), dkms:amd64 (2.2.0.3-2, automatic),
libalgorithm-diff-xs-perl:amd64 (0.04-3+b1, automatic), libtsan0:amd64 (4.9.2-10, automatic), dpkg-dev:amd64 (1.17.25, automatic), libcilkrts5:amd64 (4.9.2-10, automatic), libalgorithm-merge-perl:amd64 (0.08-2, automatic), libc-dev-bin:amd64 (2.19-18, automatic), zfsutils:amd64 (0.6.4-1.2-1, automatic), linux-headers-3.16.0-4-amd64:amd64 (3.16.7-ckt11-1, automatic), g++:amd64 (4.9.2-2, automatic), spl:amd64 (0.6.4-1b, automatic), libatomic1:amd64 (4.9.2-10, automatic), libalgorithm-diff-perl:amd64 (1.19.02-3, automatic), libmpfr4:amd64 (3.1.2-2, automatic), g++-4.9:amd64 (4.9.2-10, automatic), debian-zfs:amd64 (7~jessie), binutils:amd64 (2.25-5, automatic), libnvpair1:amd64 (0.6.4-1.2-1, automatic), gcc:amd64 (4.9.2-2, automatic), libuutil1:amd64 (0.6.4-1.2-1, automatic), libgcc-4.8-dev:amd64 (4.8.4-1, automatic), libdpkg-perl:amd64 (1.17.25, automatic), cpp:amd64 (4.9.2-2, automatic), libfakeroot:amd64 (1.20.2-1, automatic), gcc-4.8:amd64 (4.8.4-1, automatic), gcc-4.9:amd64 (4.9.2-10, automatic), libcloog-isl4:amd64 (0.18.2-1+b2, automatic), libzpool2:amd64 (0.6.4-1.2-1, automatic), spl-dkms:amd64 (0.6.4-1b, automatic), linux-compiler-gcc-4.8-x86:amd64 (3.16.7-ckt11-1, automatic), manpages-dev:amd64 (3.74-1, automatic), build-essential:amd64 (11.7, automatic), zfs-dkms:amd64 (0.6.4-1.2-1, automatic), libgcc-4.9-dev:amd64 (4.9.2-10, automatic), libzfs2:amd64 (0.6.4-1.2-1, automatic), linux-headers-amd64:amd64 (3.16+63, automatic), linux-libc-dev:amd64 (3.16.7-ckt11-1, automatic), liblsan0:amd64 (4.9.2-10, automatic), linux-headers-3.16.0-4-common:amd64 (3.16.7-ckt11-1, automatic), libitm1:amd64 (4.9.2-10, automatic), libc6-dev:amd64 (2.19-18, automatic),';
$subst = "";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php