diff --git a/wait-for b/wait-for
index c112be6..5c413d0 100755
--- a/wait-for
+++ b/wait-for
@@ -1,10 +1,10 @@
 #!/bin/sh
 
-TIMEOUT=15
-QUIET=0
+WAITFOR_TIMEOUT=15
+WAITFOR_QUIET=0
 
 echoerr() {
-  if [ "$QUIET" -ne 1 ]; then printf "%s\n" "$*" 1>&2; fi
+  if [ "$WAITFOR_QUIET" -ne 1 ]; then printf "%s\n" "$*" 1>&2; fi
 }
 
 usage() {
@@ -13,15 +13,15 @@ usage() {
 Usage:
   $0 host:port [-t timeout] [-- command args]
   -q | --quiet                        Do not output any status messages
-  -t TIMEOUT | --timeout=timeout      Timeout in seconds, zero for no timeout
+  -t WAITFOR_TIMEOUT | --timeout=timeout      Timeout in seconds, zero for no timeout
   -- COMMAND ARGS                     Execute command with args after the test finishes
 USAGE
   exit "$exitcode"
 }
 
 wait_for() {
-  for _ in $(seq $TIMEOUT) ; do
-    nc -z "$HOST" "$PORT" > /dev/null 2>&1
+  for _ in $(seq $WAITFOR_TIMEOUT) ; do
+    nc -z "$WAITFOR_HOST" "$WAITFOR_PORT" > /dev/null 2>&1
 
     result=$?
     if [ $result -eq 0 ] ; then
@@ -40,21 +40,21 @@ while [ $# -gt 0 ]
 do
   case "$1" in
     *:* )
-    HOST=$(printf "%s\n" "$1"| cut -d : -f 1)
-    PORT=$(printf "%s\n" "$1"| cut -d : -f 2)
+    WAITFOR_HOST=$(printf "%s\n" "$1"| cut -d : -f 1)
+    WAITFOR_PORT=$(printf "%s\n" "$1"| cut -d : -f 2)
     shift 1
     ;;
     -q | --quiet)
-    QUIET=1
+    WAITFOR_QUIET=1
     shift 1
     ;;
     -t)
-    TIMEOUT="$2"
-    if [ "$TIMEOUT" = "" ]; then break; fi
+    WAITFOR_TIMEOUT="$2"
+    if [ "$WAITFOR_TIMEOUT" = "" ]; then break; fi
     shift 2
     ;;
     --timeout=*)
-    TIMEOUT="${1#*=}"
+    WAITFOR_TIMEOUT="${1#*=}"
     shift 1
     ;;
     --)
@@ -76,7 +76,7 @@ if ! [ -x "$(command -v nc)" ]; then
   exit 1
 fi
 
-if [ "$HOST" = "" ] || [ "$PORT" = "" ]; then
+if [ "$WAITFOR_HOST" = "" ] || [ "$WAITFOR_PORT" = "" ]; then
   echoerr "Error: you need to provide a host and port to test."
   usage 2
 fi