Implement running commands

env/env.go

@@ -1,21 +1,39 @@
 package main
 
 import (
-	"flag"
 	"os"
+	"os/exec"
+
+	"gopkg.in/alecthomas/kingpin.v2"
 	common "source.heropunch.io/tomo/go-coreutils"
 )
 
-var ignoreEnv = flag.Bool(
-	"i",
-	false,
-	"Completely ignore the existing environment and execute cmd only with each (var, value) tuple specified.",
-)
-
 func main() {
-	flag.Parse()
+	app := kingpin.New("env", "modify the environment, then print it or run a command")
+	ignoreEnv := kingpin.Flag(
+		"ignore-environment",
+		"Completely ignore the existing environment and execute cmd only with each (var, value) tuple specified.",
+	).Short('i').Bool()
+	unset := kingpin.Flag("unset", "Unset var in the environment.").PlaceHolder("var").Short('u').Strings()
+
+	cmd := kingpin.Arg("cmd", "").String()
+	args := kingpin.Arg("args", "").Strings()
+
+	kingpin.Parse()
+
+	for _, key := range *unset {
+		os.Unsetenv(key)
+	}
+
 	if *ignoreEnv {
 		os.Clearenv()
 	}
-	common.PrintEnv()
+
+	if *cmd == "" {
+		common.PrintEnv()
+		os.Exit(0)
+	}
+	command := exec.Command(*cmd, *args...)
+	err := command.Run()
+	app.FatalIfError(err, "error running command:")
 }

go.mod

@@ -1,6 +1,9 @@
 module source.heropunch.io/tomo/go-coreutils
 
 require (
+	github.com/alecthomas/template v0.0.0-20160405071501-a0175ee3bccc // indirect
+	github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf // indirect
 	github.com/alexflint/go-arg v1.0.0
 	github.com/stretchr/testify v1.3.0
+	gopkg.in/alecthomas/kingpin.v2 v2.2.6
 )

go.sum

@@ -1,3 +1,7 @@
+github.com/alecthomas/template v0.0.0-20160405071501-a0175ee3bccc h1:cAKDfWh5VpdgMhJosfJnn5/FoN2SRZ4p7fJNX58YPaU=
+github.com/alecthomas/template v0.0.0-20160405071501-a0175ee3bccc/go.mod h1:LOuyumcjzFXgccqObfd/Ljyb9UuFJ6TxHnclSeseNhc=
+github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf h1:qet1QNfXsQxTZqLG4oE62mJzwPIB8+Tee4RNCL9ulrY=
+github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf/go.mod h1:ybxpYRFXyAe+OPACYpWeL0wqObRcbAqCMya13uyzqw0=
 github.com/alexflint/go-arg v1.0.0 h1:VWNnY3DyBHiq5lcwY2FlCE5t5qyHNV0o5i1bkCIHprU=
 github.com/alexflint/go-arg v1.0.0/go.mod h1:Cto8k5VtkP4pp0EXiWD4ZJMFOOinZ38ggVcQ/6CGuRI=
 github.com/alexflint/go-scalar v1.0.0 h1:NGupf1XV/Xb04wXskDFzS0KWOLH632W/EO4fAFi+A70=
@@ -15,3 +19,5 @@ github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.3.0 h1:TivCn/peBQ7UY8ooIcPgZFpTNSz0Q2U6UrFlUfqbe0Q=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
+gopkg.in/alecthomas/kingpin.v2 v2.2.6 h1:jMFz6MfLP0/4fUyZle81rXUoxOBFi19VUFKVDOQfozc=
+gopkg.in/alecthomas/kingpin.v2 v2.2.6/go.mod h1:FMv+mEhP44yOT+4EoQTLFTRgOQ1FBLkstjWtayDeSgw=