ambrevar/shell: Add tee.

.local/share/common-lisp/source/ambrevar/shell.lisp

@@ -260,6 +260,15 @@ to get the final output as a string."
     (values (uiop:process-info-output handler)
             handler)))
 
+(export-always 'tee)
+(defun tee (input-stream)
+  "Return the INPUT-STREAM and its string representation as a second value."
+  (let ((result
+          (uiop:slurp-stream-string input-stream :stripped t)))
+    (values
+     (make-string-input-stream result)
+     result)))
+
 (export-always 'disk-usage)
 (defun disk-usage (files)
   "Return disk usage of FILES in octets.