cmd: force no color output when NO_COLOR env presents

cmd/constant.go

@@ -1,5 +1,7 @@
 package cmd
 
+import "os"
+
 var unwrapScalarFlag = newUnwrapFlag()
 
 var unwrapScalar = false
@@ -12,9 +14,6 @@ var outputFormat = ""
 var inputFormat = ""
 
 var exitStatus = false
-var forceColor = false
-var forceNoColor = false
-var colorsEnabled = false
 var indent = 2
 var noDocSeparators = false
 var nullInput = false
@@ -23,6 +22,16 @@ var verbose = false
 var version = false
 var prettyPrint = false
 
+var forceColor = false
+var forceNoColor = false
+var colorsEnabled = false
+
+func init() {
+	// when NO_COLOR environment variable presents and not an empty string the colored output should be disabled;
+	// refer to no-color.org
+	forceNoColor = os.Getenv("NO_COLOR") != ""
+}
+
 // can be either "" (off), "extract" or "process"
 var frontMatter = ""
 

cmd/root.go

@@ -182,7 +182,7 @@ yq -P -oy sample.json
 	rootCmd.PersistentFlags().BoolVarP(&exitStatus, "exit-status", "e", false, "set exit status if there are no matches or null or false is returned")
 
 	rootCmd.PersistentFlags().BoolVarP(&forceColor, "colors", "C", false, "force print with colors")
-	rootCmd.PersistentFlags().BoolVarP(&forceNoColor, "no-colors", "M", false, "force print with no colors")
+	rootCmd.PersistentFlags().BoolVarP(&forceNoColor, "no-colors", "M", forceNoColor, "force print with no colors")
 	rootCmd.PersistentFlags().StringVarP(&frontMatter, "front-matter", "f", "", "(extract|process) first input as yaml front-matter. Extract will pull out the yaml content, process will run the expression against the yaml content, leaving the remaining data intact")
 	if err = rootCmd.RegisterFlagCompletionFunc("front-matter", cobra.FixedCompletions([]string{"extract", "process"}, cobra.ShellCompDirectiveNoFileComp)); err != nil {
 		panic(err)