Some examples:

if ($line =~ /^raster\|/) {
if ( defined $GL_ACCESS_LOG) {}
if ($locnumber > $N_GL_USERS) {
if ( $project{rasteron} == 1) {
if ($coord{proj} != 3) {&get_coords;}
if ( (! $value{RASTER}) && (! $value{VECTOR}) && (! $value{SITES}) ) {
if (!( -r $fileOne && -r $fileTwo && -r $fileThree)) {
if (!$value{ZOOM} || $value{ZOOM} == 0) {
if ( $value{RASTERQUERY} && $value{RASTERQUERY} ne "none" ) {
if (! @rasts) {# if no rasters selected
if ($value{UNITS} eq "me") {