Support /dev/disk/by-id/ symlinks in command-line installer (#1422)

* Allow symlinks as target device (for supporting /dev/disk/by-id)

* Use correct test (-L) for checking if it is a symlink

Co-authored-by: Jakob Lell <jakob@srlabs.com>

INSTALL/tool/VentoyWorker.sh

@@ -60,6 +60,12 @@ while [ -n "$1" ]; do
             exit 1
         fi
         DISK=$1
+        # Resolve symlinks now, will be needed to look up information about the device in
+        # the /sys/ filesystem, for example /sys/class/block/${DISK#/dev/}/start
+        # The main use case is supporting /dev/disk/by-id/ symlinks instead of raw devices
+        if [ -L "$DISK" ]; then
+            DISK=$(readlink -e -n "$DISK")
+        fi
     fi
 
     shift