diff --git a/sbin/gentoo-upgrade.sh b/sbin/gentoo-upgrade.sh
index f5dbaf4..81ffeba 100755
--- a/sbin/gentoo-upgrade.sh
+++ b/sbin/gentoo-upgrade.sh
@@ -1,7 +1,7 @@
 #!/bin/bash
 
 STAGE=0
-NICE_CMD=nice -n 19 ionice -c2 -n7
+NICE_CMD="nice -n 19 ionice -c2 -n7"
 
 source /etc/make.conf
 [ -f /etc/gentoo-upgrade.conf ] && source /etc/gentoo-upgrade.conf
diff --git a/sbin/kernel-clean.sh b/sbin/kernel-clean.sh
index 575c102..7122ff3 100755
--- a/sbin/kernel-clean.sh
+++ b/sbin/kernel-clean.sh
@@ -1,6 +1,6 @@
 #!/bin/bash
 
-NICE_CMD=nice -n 19 ionice -c2 -n7
+NICE_CMD="nice -n 19 ionice -c2 -n7"
 
 REVISION=`kernel-config list | grep \*$ | cut -d" " -f6 | cut -d- -f2-8`
 [ "" == "$REVISION" ] && echo "No appropriate kernel revision found ;-(" && exit -1
diff --git a/sbin/kernel-rebuild.sh b/sbin/kernel-rebuild.sh
index 57753ea..ca7b44f 100755
--- a/sbin/kernel-rebuild.sh
+++ b/sbin/kernel-rebuild.sh
@@ -1,7 +1,7 @@
 #!/bin/bash
 
 SILENT=false
-NICE_CMD=nice -n 19 ionice -c2 -n7
+NICE_CMD="nice -n 19 ionice -c2 -n7"
 
 # available parameters
 eval set -- "`getopt -o hs --long help,silent -- \"$@\"`"