diff --git a/install_amavis.sh b/install_amavis.sh
index 891a3cb..8cc85f2 100755
--- a/install_amavis.sh
+++ b/install_amavis.sh
@@ -963,7 +963,6 @@ else
 fi
 
 echononl "   Disable crontab for user root"
-echo "" >> ${logdir}/main.log
 echo "crontab -r -u root" > $tmp_err_msg
 crontab -r -u root > $tmp_err_msg  2>&1
 if [[ "$?" = "0" ]]; then
diff --git a/install_postfixadmin.sh b/install_postfixadmin.sh
index a6a9e5e..66675f5 100755
--- a/install_postfixadmin.sh
+++ b/install_postfixadmin.sh
@@ -148,7 +148,7 @@ if $systemd_supported ; then
 	# -
 	if systemctl -t service list-unit-files \
 			| grep -e "^apache2.service" \
-			| grep -q -E "(enabled|disabled)" 2> /devnull ; then
+			| grep -q -E "(enabled|disabled)" 2> /dev/null ; then
 
 		APACHE_SERVICE_FILE=$(systemctl -t service list-unit-files \
 										| grep -e "^apache2.service" \
diff --git a/install_roundcube.sh b/install_roundcube.sh
index 207b0b9..8aed0fb 100755
--- a/install_roundcube.sh
+++ b/install_roundcube.sh
@@ -109,7 +109,7 @@ if $systemd_supported ; then
    # -
    if systemctl -t service list-unit-files \
          | grep -e "^apache2.service" \
-         | grep -q -E "(enabled|disabled)" 2> /devnull ; then
+         | grep -q -E "(enabled|disabled)" 2> /dev/null ; then
 
       APACHE_SERVICE_FILE=$(systemctl -t service list-unit-files \
                               | grep -e "^apache2.service" \
diff --git a/upgrade_roundcube.sh b/upgrade_roundcube.sh
index a113aa3..2b8f235 100755
--- a/upgrade_roundcube.sh
+++ b/upgrade_roundcube.sh
@@ -133,7 +133,7 @@ if $systemd_supported ; then
    # -
    if systemctl -t service list-unit-files \
          | grep -e "^apache2.service" \
-         | grep -q -E "(enabled|disabled)" 2> /devnull ; then
+         | grep -q -E "(enabled|disabled)" 2> /dev/null ; then
 
       APACHE_SERVICE_FILE=$(systemctl -t service list-unit-files \
                               | grep -e "^apache2.service" \
@@ -457,23 +457,21 @@ echo -e "\n\n   \033[37m\033[1mSome pre-installation tasks..\033[m\n"
 ## - Disable crontab for user root
 ## -
 echononl "   Backup crontab"
-echo "" >> ${logdir}/main.log
-echo "crontab -u root -l > $crontab_backup_file" >> ${logdir}/main.log
-crontab -u root -l >> $crontab_backup_file 2>> ${logdir}/main.log
+crontab -u root -l >> $crontab_backup_file 2> $log_file
 if [[ "$?" = "0" ]]; then
    echo_ok
 else
    echo_failed
+   error "$(cat $log_file)"
 fi
 
 echononl "   Disable crontab for user root"
-echo "" >> ${logdir}/main.log
-echo "crontab -r -u root" >> ${logdir}/main.log
-crontab -r -u root >> ${logdir}/main.log 2>&1
+crontab -r -u root > $log_file 2>&1
 if [[ "$?" = "0" ]]; then
    echo_ok
 else
    echo_failed
+   error "$(cat $log_file)"
 fi