diff --git a/CHANGELOG.md b/CHANGELOG.md
index 31e1fa2..6701933 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,8 @@
 
 ## master (unreleased)
 
+* [#135](https://github.com/clojure-emacs/inf-clojure/pull/135): Improve command sanitation code.
+
 ## 2.1.0 (2018-01-02)
 
 ### New Features
diff --git a/inf-clojure.el b/inf-clojure.el
index 385b149..51ecfee 100644
--- a/inf-clojure.el
+++ b/inf-clojure.el
@@ -303,10 +303,10 @@ It requires a REPL PROC for inspecting the correct type."
 
 (defun inf-clojure--single-linify (string)
   "Convert a multi-line STRING in a single-line STRING.
-It also reduces/adds redundant whitespace for readability.  Note
-that this function will transform the empty string in \" \" (it
-adds an empty space)."
-  (replace-regexp-in-string "[ \\|\n]+" " " string))
+It also reduces redundant whitespace for readability."
+  (thread-last string
+    (replace-regexp-in-string "[ \\|\n]+" " ")
+    (replace-regexp-in-string " $" "")))
 
 (defun inf-clojure--trim-newline-right (string)
   "Trim newlines (only) in STRING."
@@ -334,7 +334,10 @@ always be preferred over `comint-send-string`.  It delegates to
 the string for evaluation.  Refer to `comint-simple-send` for
 customizations."
   (inf-clojure--set-repl-type proc)
-  (comint-simple-send proc string))
+  (let ((sanitized (inf-clojure--sanitize-command string)))
+    (when (not (string-empty-p sanitized))
+      (inf-clojure--log-string sanitized "----CMD->")
+      (comint-simple-send proc sanitized))))
 
 (defcustom inf-clojure-load-form "(clojure.core/load-file \"%s\")"
   "Format-string for building a Clojure expression to load a file.
@@ -555,6 +558,7 @@ to continue it."
 
 (defun inf-clojure-preoutput-filter (str)
   "Preprocess the output STR from interactive commands."
+  (inf-clojure--log-string str "<-RES----")
   (cond
    ((string-prefix-p "inf-clojure-" (symbol-name (or this-command last-command)))
     ;; Remove subprompts and prepend a newline to the output string
@@ -1173,7 +1177,7 @@ STRING if present."
                               (concat tag "\n")
                               (concat (prin1-to-string tag) "\n")))
                           (let ((print-escape-newlines t))
-                            (prin1-to-string string)))
+                            (prin1-to-string (substring-no-properties string))))
                   nil
                   (expand-file-name inf-clojure--log-file-name
                                     (inf-clojure-project-root))
diff --git a/test/inf-clojure-tests.el b/test/inf-clojure-tests.el
index 994801c..6147dd3 100644
--- a/test/inf-clojure-tests.el
+++ b/test/inf-clojure-tests.el
@@ -111,4 +111,24 @@
          (expect (ict-bounds-string (inf-clojure-completion-bounds-of-expr-at-point))
                  :to-equal "deref")))))
 
+(describe "inf-clojure--single-linify"
+  (it "replaces newlines with whitespace"
+      (expect (inf-clojure--single-linify "(do\n(println \"hello world\")\n)") :to-equal "(do (println \"hello world\") )"))
+
+  (it "does not leave whitespace at the end"
+      (expect (inf-clojure--single-linify "(do\n(println \"hello world\")\n)\n\n") :to-equal "(do (println \"hello world\") )"))
+
+  (it "returns empty string in case of only newline"
+      (expect (inf-clojure--single-linify "\n\n\n\n") :to-equal "")))
+
+(describe "inf-clojure--sanitize-command"
+  (it "sanitizes the command correctly"
+     (expect (inf-clojure--sanitize-command "(doc println)") :to-equal "(doc println)\n"))
+
+  (it "trims newline at the right of a command"
+     (expect (inf-clojure--sanitize-command "(doc println)\n\n\n\n") :to-equal "(doc println)\n"))
+
+  (it "returns empty string when the command is empty"
+     (expect (inf-clojure--sanitize-command "   ") :to-equal "")))
+
 ;;; inf-clojure-tests.el ends here