zshcd: fixed void variables

.scripts/zshcd

@@ -1,9 +1,13 @@
 #!/bin/sh
 ## Start zsh in directory specified as first argument.
 
+if [ ! -d "$1" ]; then
+    zsh
+    exit
+fi
+
 ## Default files.
 ZDIRS="$HOME/.cache/zsh/dirs"
-SHELL_DIR="$HOME/.shell.d"
 
 ## Fetch file location dynamically.
 if [ ! -f "$ZDIRS" ]; then
@@ -12,24 +16,30 @@ if [ ! -f "$ZDIRS" ]; then
         exit
     fi
         
-    SHELL_DIR_GREP="$(grep "SHELL_DIR=" ~/.zshrc | cut -f2 -d=)"
-    [ -n "$SHELL_DIR_GREP" ] && SHELL_DIR="$(eval echo "$SHELL_DIR_GREP")"
+    SHELL_DIR="$HOME/.shell.d"
+    if [ ! -d "$SHELL_DIR" ]; then
+        SHELL_DIR_GREP="$(grep "SHELL_DIR=" ~/.zshrc | cut -f2 -d=)"
+        [ -n "$SHELL_DIR_GREP" ] && SHELL_DIR="$(eval echo "$SHELL_DIR_GREP")"
+    fi
+    if [ ! -d "$SHELL_DIR" ]; then
+        echo 'DIRSTACKFILE and SHELL_DIR not found. Exiting.'
+        exit
+    fi
     ZDIRS_GREP="$(grep -rm1 'DIRSTACKFILE=' "$SHELL_DIR" | cut -f2 -d=)"
     [ -n "$ZDIRS_GREP" ] && ZDIRS="$(eval echo "$ZDIRS_GREP")"
 fi
 
 if [ ! -f "$ZDIRS" ]; then
     echo 'DIRSTACKFILE not found. Exiting.'
+    exit
 fi
 
-if [ ! -d "$1" ]; then
-    zsh
-else
-    if [ -n "$(grep "$1" "$ZCACHE")" ]; then
-        BUF="$(grep -v "$1" "$ZCACHE")"
-        echo "$BUF"
-        echo "$BUF" > "$ZCACHE"
-    fi
-    prepend "$1" "$ZCACHE"
-    zsh
-fi
+if [ -n "$(grep "$1" "$ZDIRS")" ]; then
+    BUF="$(grep -v "$1" "$ZDIRS")"
+    echo "$BUF"
+    echo "$BUF" > "$ZDIRS"
+fi
+
+prepend "$1" "$ZDIRS"
+zsh
+