diff --git a/.travis.yml b/.travis.yml
index 333bef1..0eb96bd 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,26 +1,25 @@
 language: go
 env:
   - GIMME_OS=linux GIMME_ARCH=amd64
-  - GIMME_OS=darwin GIMME_ARCH=amd64
-  - GIMME_OS=windows GIMME_ARCH=amd64
+#  - GIMME_OS=darwin GIMME_ARCH=amd64
+#  - GIMME_OS=windows GIMME_ARCH=amd64
 sudo: required
 go:
-  - 1.6.3
-  - 1.7
-  - 1.8.3
+  - 1.9
   - tip
 install:
   - go get -d -v -t ./...
 script:
   - export GOMAXPROCS=$(nproc) GOOS=$GIMME_OS GOARCH=$GIMME_ARCH
   # TODO test seems to fail on non linux platforms @ travis
-#  - go test -v -timeout=30s ./...
+  - go test -v -timeout=30s ./...
   - go build -o tg ./cli/cli.go
 deploy:
   provider: releases
   api_key:
     secure: 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
-  file: tg
+  file:
+  - tg
   skip_cleanup: true
   on:
     tags: true
@@ -28,5 +27,3 @@ matrix:
   fast_finish: true
   allow_failures:
   - go: tip
-  exclude:
-  - go: 1.6.3
\ No newline at end of file
diff --git a/README.md b/README.md
index 2b0e15d..b09ce23 100644
--- a/README.md
+++ b/README.md
@@ -6,17 +6,24 @@ Environment variable based template engine like Jinja2 for your container config
 
 ## Usage
 
-Define variables with the format `{{ VAR_IABLE }}` and set them in your environment before **tg** execution.
+Define variables with the format `{{ VAR_IABLE }}` inside your template files and set them in your environment before **tg** execution.
 
-Currently with stdin/stdout support.
- ```
+Currently with stdin/stdout and inline support.
+ 
+ ```bash
+# pipe
 TESTVAR=foo cat /opt/templates/file1.ext | tg > /dest/config/file1.ext
+# or inline
+TESTVAR=foo tg -i /dest/config/file1.ext
  ```
+ 
+However, using the inline option on your templates will overwrite them.
+It is recommended to use this option on resettable files.
 
 ### TODO
 * flags for file in/out
 * prefix flag for env var e.g. SERVICE_XXX
 
-### Licence
+### License
 
 MIT
diff --git a/cli/cli.go b/cli/cli.go
index a75be6f..77f9150 100644
--- a/cli/cli.go
+++ b/cli/cli.go
@@ -1,40 +1,67 @@
 package main
 
 import (
-	"fmt"
-	"github.com/malud/temgo/temgo"
+	"bufio"
+	"flag"
 	"io/ioutil"
 	"os"
 	"strings"
+
+	"github.com/malud/temgo/temgo"
 )
 
 var envVars = make(temgo.EnvVars)
+var inlineFlag = flag.String("i", "", "-i filename")
 
-// Initialize and filter all non upper case variables.
 func init() {
 	for _, e := range os.Environ() {
 		string := strings.Split(e, "=")
-		if strings.Compare(string[0], strings.ToUpper(string[0])) == 0 {
-			envVars[string[0]] = string[1]
-		}
+		envVars[string[0]] = string[1]
+	}
+
+	if !flag.Parsed() {
+		flag.Parse()
 	}
 }
 
 func main() {
-	var writeErr error
-	input := os.Stdin
-	bytes, err := ioutil.ReadAll(input)
-	if err != nil {
-		_, writeErr = os.Stderr.WriteString(fmt.Sprintf("Could not read: %v", err))
+	var rw *bufio.ReadWriter
+	var file *os.File
+	if *inlineFlag != "" {
+		var err error
+		file, err = os.OpenFile(*inlineFlag, os.O_RDWR, 644)
+		must(err)
+		defer file.Close()
+		rw = bufio.NewReadWriter(bufio.NewReader(file), bufio.NewWriter(file))
+	} else {
+		rw = bufio.NewReadWriter(bufio.NewReader(os.Stdin), bufio.NewWriter(os.Stdout))
 	}
+
+	bytes, err := ioutil.ReadAll(rw)
+	must(err)
+
 	if temgo.ContainsVariable(bytes) {
 		str := envVars.ReplaceVariables(bytes)
-		_, err = os.Stdout.Write(str)
-		if err != nil {
-			_, writeErr = os.Stderr.WriteString(fmt.Sprintf("Could not write: %v", err))
+		if file != nil {
+			truncate(file)
 		}
+		_, err := rw.Write(str)
+		must(err)
+		must(rw.Flush())
 	}
-	if writeErr != nil {
-		panic(writeErr)
+}
+
+// fatal
+func must(err error) {
+	if err != nil {
+		println("Err:", err.Error())
+		os.Exit(1)
 	}
 }
+
+func truncate(file *os.File) {
+	err := file.Truncate(0)
+	must(err)
+	_, err = file.Seek(0, 0)
+	must(err)
+}