diff --git a/support/bin/rtcds.in b/support/bin/rtcds.in
index c656cfad0a17759c5da9fdc86861640de3462117..e61464684d1b39eb1b0fde3668333c625fb55e0d 100755
--- a/support/bin/rtcds.in
+++ b/support/bin/rtcds.in
@@ -35,7 +35,7 @@ RCG_BUILD_ROOT=${RCG_BUILD_ROOT:-/var/cache/advligorts}
 RCG_BUILDD=${RCG_BUILDD:-$RCG_BUILD_ROOT/rcg-$RTS_VERSION}
 # FIXME: the RCG hard-codes /opt/rtcds as the root, you can use a custom
 # RCG_TARGET for building only
-RCG_TARGET=${RCG_TARGET-"/opt/rtcds/${site}/${ifo}"}
+RCG_TARGET=${RCG_TARGET:-"/opt/rtcds/${site}/${ifo}"}
 
 # search paths for C source code
 CDS_SRC=${CDS_SRC:-$RCG_LIB_PATH}