Added shell string encoder (@sh) #1526

pkg/yqlib/doc/operators/encode-decode.md

@@ -17,6 +17,7 @@ These operators are useful to process yaml documents that have stringified embed
 | XML | from_xml/@xmld | to_xml(i)/@xml |
 | Base64 | @base64d | @base64 |
 | URI | @urid | @uri |
+| Shell |  | @sh |
 
 
 See CSV and TSV [documentation](https://mikefarah.gitbook.io/yq/usage/csv-tsv) for accepted formats.
@@ -464,6 +465,22 @@ will output
 this has & special () characters *
 ```
 
+## Encode a string to sh
+Sh/Bash friendly string
+
+Given a sample.yml file of:
+```yaml
+coolData: strings with spaces and a 'quote'
+```
+then
+```bash
+yq '.coolData | @sh' sample.yml
+```
+will output
+```yaml
+'strings with spaces and a \'quote\''
+```
+
 ## Decode a base64 encoded string
 Decoded data is assumed to be a string.
 

pkg/yqlib/doc/operators/headers/encode-decode.md

@@ -17,6 +17,7 @@ These operators are useful to process yaml documents that have stringified embed
 | XML | from_xml/@xmld | to_xml(i)/@xml |
 | Base64 | @base64d | @base64 |
 | URI | @urid | @uri |
+| Shell |  | @sh |
 
 
 See CSV and TSV [documentation](https://mikefarah.gitbook.io/yq/usage/csv-tsv) for accepted formats.

pkg/yqlib/encoder_sh.go

@@ -0,0 +1,44 @@
+package yqlib
+
+import (
+	"fmt"
+	"io"
+	"regexp"
+	"strings"
+
+	yaml "gopkg.in/yaml.v3"
+)
+
+var pattern = regexp.MustCompile(`[^\w@%+=:,./-]`)
+
+type shEncoder struct {
+}
+
+func NewShEncoder() Encoder {
+	return &shEncoder{}
+}
+
+func (e *shEncoder) CanHandleAliases() bool {
+	return false
+}
+
+func (e *shEncoder) PrintDocumentSeparator(writer io.Writer) error {
+	return nil
+}
+
+func (e *shEncoder) PrintLeadingContent(writer io.Writer, content string) error {
+	return nil
+}
+
+func (e *shEncoder) Encode(writer io.Writer, originalNode *yaml.Node) error {
+	node := unwrapDoc(originalNode)
+	if guessTagFromCustomType(node) != "!!str" {
+		return fmt.Errorf("cannot encode %v as URI, can only operate on strings. Please first pipe through another encoding operator to convert the value to a string", node.Tag)
+	}
+
+	value := originalNode.Value
+	if pattern.MatchString(value) {
+		value = "'" + strings.ReplaceAll(value, "'", "\\'") + "'"
+	}
+	return writeString(writer, value)
+}

pkg/yqlib/lexer_participle.go

@@ -80,6 +80,7 @@ var participleYqRules = []*participleYqRule{
 
 	{"Urid", `@urid`, decodeOp(UriInputFormat), 0},
 	{"Uri", `@uri`, encodeWithIndent(UriOutputFormat, 0), 0},
+	{"SH", `@sh`, encodeWithIndent(ShOutputFormat, 0), 0},
 
 	{"LoadXML", `load_?xml|xml_?load`, loadOp(NewXMLDecoder(ConfiguredXMLPreferences), false), 0},
 

pkg/yqlib/operator_encoder_decoder.go

@@ -28,6 +28,8 @@ func configureEncoder(format PrinterOutputFormat, indent int) Encoder {
 		return NewBase64Encoder()
 	case UriOutputFormat:
 		return NewUriEncoder()
+	case ShOutputFormat:
+		return NewShEncoder()
 	}
 	panic("invalid encoder")
 }

pkg/yqlib/operator_encoder_decoder_test.go

@@ -257,6 +257,15 @@ var encoderDecoderOperatorScenarios = []expressionScenario{
 			"D0, P[], (!!str)::this has & special () characters *\n",
 		},
 	},
+	{
+		description:    "Encode a string to sh",
+		subdescription: "Sh/Bash friendly string",
+		document:       "coolData: strings with spaces and a 'quote'",
+		expression:     ".coolData | @sh",
+		expected: []string{
+			"D0, P[coolData], (!!str)::'strings with spaces and a \\'quote\\''\n",
+		},
+	},
 	{
 		description:    "Decode a base64 encoded string",
 		subdescription: "Decoded data is assumed to be a string.",

pkg/yqlib/printer.go

@@ -28,6 +28,7 @@ const (
 	XMLOutputFormat
 	Base64OutputFormat
 	UriOutputFormat
+	ShOutputFormat
 )
 
 func OutputFormatFromString(format string) (PrinterOutputFormat, error) {