Adding sanitation for the use command to make sure a file exists first

.gitignore

@@ -23,6 +23,9 @@
 /vendor/
 /Godeps/
 
+### VSCode ###
+.vscode
+
 ### JetBrains ###
 # Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm, CLion, Android Studio and WebStorm
 # Reference: https://intellij-support.jetbrains.com/hc/en-us/articles/206544839
@@ -105,4 +108,4 @@ fabric.properties
 # Sonarlint plugin
 .idea/sonarlint
 
-# End of https://www.gitignore.io/api/go,jetbrains
+# End of https://www.gitignore.io/api/go,jetbrains

cmd/use_darwin.go

@@ -1,4 +1,4 @@
-// +build darwin
+// +build linux
 
 /*
 Copyright © 2019 Zee Ahmed <zee@simplyzee.dev>
@@ -62,6 +62,12 @@ func UseKubectlBinary(version string) error {
 	kubectlVersion := homeDir + "/.kubemngr/kubectl-" + version
 	kubectlLink := homeDir + "/.local/bin/kubectl"
 
+	_, err = os.Stat(kubectlVersion)
+	if os.IsNotExist(err) {
+		log.Printf("kubectl %s does not exist", version)
+		os.Exit(1)
+	}
+
 	if _, err := os.Lstat(kubectlLink); err == nil {
 		os.Remove(kubectlLink)
 	}

cmd/use_linux.go

@@ -62,6 +62,12 @@ func UseKubectlBinary(version string) error {
 	kubectlVersion := homeDir + "/.kubemngr/kubectl-" + version
 	kubectlLink := homeDir + "/.local/bin/kubectl"
 
+	_, err = os.Stat(kubectlVersion)
+	if os.IsNotExist(err) {
+		log.Printf("kubectl %s does not exist", version)
+		os.Exit(1)
+	}
+
 	if _, err := os.Lstat(kubectlLink); err == nil {
 		os.Remove(kubectlLink)
 	}