From 427a7118ac44b7c76f260f0068ba201a147bd6c3 Mon Sep 17 00:00:00 2001
From: Hugo Osvaldo Barrera <hugo@barrera.io>
Date: Mon, 2 Feb 2015 13:14:39 -0300
Subject: [PATCH] Only add `--color` to grep's alias if that option is valid.

The option `--color` is not available on all versions of grep. This change
verifies that the option is valid before adding it to the alias used by
default.
---
 lib/grep.zsh | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/grep.zsh b/lib/grep.zsh
index 348ebe623..2c254bab0 100644
--- a/lib/grep.zsh
+++ b/lib/grep.zsh
@@ -3,8 +3,12 @@ grep-flag-available() {
     echo | grep $1 "" >/dev/null 2>&1
 }
 
+GREP_OPTIONS=""
+
 # color grep results
-GREP_OPTIONS="--color=auto"
+if grep-flag-available --color=auto; then
+    GREP_OPTIONS+="--color=auto"
+fi
 
 # ignore VCS folders (if the necessary grep flags are available)
 VCS_FOLDERS="{.bzr,.cvs,.git,.hg,.svn}"