mysqlshow is no longer available on debian 13 (trixie).

install_nextcloud.sh

@@ -240,7 +240,7 @@ systemd_supported=false
 systemd=$(which systemd)
 systemctl=$(which systemctl)
 
-if [[ -n "$systemd" ]] && [[ -n "$systemctl" ]] ; then
+if [[ -n "$systemd" ]] || [[ -n "$systemctl" ]] ; then
    systemd_supported=true
 fi
 
@@ -2704,7 +2704,14 @@ checks_all_is_fine=true
 # -
 
 if [[ "$DATABASE_TYPE" = "mysql" ]] ; then
-   if [[ ! "$(mysqlshow -h $DATABASE_HOST -u $DATABASE_USER -p$DATABASE_PASS $DATABASE_NAME 2>/dev/null)" ]] ; then
+
+   if ! mysql \
+      -h "$DATABASE_HOST" \
+      -u "$DATABASE_USER" \
+      -p"$DATABASE_PASS" \
+      "$DATABASE_NAME" \
+      -e "SELECT 1;" >/dev/null 2>&1
+   then
       fatal "Cannot connect database \033[1m$DATABASE_NAME\033[m!"
    fi