diff --git a/doc_src/isatty.txt b/doc_src/isatty.txt
new file mode 100644
index 000000000..5654c5a2b
--- /dev/null
+++ b/doc_src/isatty.txt
@@ -0,0 +1,12 @@
+\section isatty isatty - Test if the specidied file descriptor is a tty
+
+\subsection isatty-synopsis Synopsis
+ <tt>isatty [FILE DESCRIPTOR]</tt>
+
+where FILE DESCRIPTOR may be either the number of a file descriptor, or one
+of the strings stdin, stdout and stderr.
+
+If he specified file descriptor is a tty, the exit status of the
+command is zero, otherwise, it is non-zero.
+
+
diff --git a/share/functions/isatty.fish b/share/functions/isatty.fish
new file mode 100644
index 000000000..3a54c6ab4
--- /dev/null
+++ b/share/functions/isatty.fish
@@ -0,0 +1,28 @@
+
+function isatty -d "Tests if a file descriptor is a tty"
+	set -l fd 0
+	if count $argv >/dev/null 
+		switch $argv[1]
+
+			case -h --h --he --hel --help
+				help isatty
+
+			case stdin
+				set fd 0
+
+			case stdout
+				set fd 1
+
+			case stderr
+				set fd 2
+
+			case '*'
+				set fd $argv[1]
+			
+		end
+	end
+
+	eval "tty 0>&$fd >/dev/null"; and return 0
+
+	return 1
+end
diff --git a/share/functions/ls.fish b/share/functions/ls.fish
index e03b33dd9..d98b19819 100644
--- a/share/functions/ls.fish
+++ b/share/functions/ls.fish
@@ -5,7 +5,11 @@
 if command ls --version 1>/dev/null 2>/dev/null
 	# This is GNU ls
 	function ls -d (N_ "List contents of directory")
-		command ls --color=auto --indicator-style=classify $argv
+		set -l param --color=auto
+		if isatty 1
+			set param $param --indicator-style=classify
+		end
+		command ls $argv
 	end
 
 	set -l color_document 35