numerous changes

+ fish & bash completions
+ -w/--where option
M moved util_readf to _reve.sh
M linter-detected warnings fixed
M less variable clutter

_reve.sh

@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+
+# reve                              desktop environment framework
+# Yigid BALABAN <fyb@fybx.dev>                               2024
+
+util_readf () {
+    local filename=$1
+
+    if [[ -f "$filename" ]]; then
+        cat "$filename"
+    else
+        echo "[reve] [E] util_readf: File not found: $filename" >&2
+        return 1
+    fi
+}