diff --git a/pkg/transformers/gsub.go b/pkg/transformers/gsub.go
deleted file mode 100644
index 0b188505b..000000000
--- a/pkg/transformers/gsub.go
+++ /dev/null
@@ -1,157 +0,0 @@
-package transformers
-
-import (
-	"container/list"
-	"fmt"
-	"os"
-	"strings"
-
-	"github.com/johnkerl/miller/pkg/bifs"
-	"github.com/johnkerl/miller/pkg/cli"
-	"github.com/johnkerl/miller/pkg/mlrval"
-	"github.com/johnkerl/miller/pkg/types"
-)
-
-// ----------------------------------------------------------------
-const verbNameGsub = "gsub"
-
-var GsubSetup = TransformerSetup{
-	Verb:         verbNameGsub,
-	UsageFunc:    transformerGsubUsage,
-	ParseCLIFunc: transformerGsubParseCLI,
-	IgnoresInput: false,
-}
-
-func transformerGsubUsage(
-	o *os.File,
-) {
-	fmt.Fprintf(o, "Usage: %s %s [options]\n", "mlr", verbNameGsub)
-	fmt.Fprintf(o, "Replaces old string with new string in specified field(s), with regex support\n")
-	fmt.Fprintf(o, "for the old string and handling multiple matches, like the `gsub` DSL function.\n")
-	fmt.Fprintf(o, "See also the `sub` and `ssub` verbs.\n")
-	fmt.Fprintf(o, "Options:\n")
-	fmt.Fprintf(o, "-f {a,b,c}  Field names to convert.\n")
-	fmt.Fprintf(o, "-h|--help   Show this message.\n")
-}
-
-func transformerGsubParseCLI(
-	pargi *int,
-	argc int,
-	args []string,
-	_ *cli.TOptions,
-	doConstruct bool, // false for first pass of CLI-parse, true for second pass
-) IRecordTransformer {
-
-	// Skip the verb name from the current spot in the mlr command line
-	argi := *pargi
-	verb := args[argi]
-	argi++
-
-	// Parse local flags
-	var fieldNames []string = nil
-	var oldText string
-	var newText string
-
-	for argi < argc /* variable increment: 1 or 2 depending on flag */ {
-		opt := args[argi]
-		if !strings.HasPrefix(opt, "-") {
-			break // No more flag options to process
-		}
-		if args[argi] == "--" {
-			break // All transformers must do this so main-flags can follow verb-flags
-		}
-		argi++
-
-		if opt == "-h" || opt == "--help" {
-			transformerGsubUsage(os.Stdout)
-			os.Exit(0)
-
-		} else if opt == "-f" {
-			fieldNames = cli.VerbGetStringArrayArgOrDie(verb, opt, args, &argi, argc)
-		} else {
-			transformerGsubUsage(os.Stderr)
-			os.Exit(1)
-		}
-	}
-
-	if fieldNames == nil {
-		transformerGsubUsage(os.Stderr)
-		os.Exit(1)
-	}
-
-	// Get the old and new text from the command line
-	if (argc - argi) < 2 {
-		transformerGsubUsage(os.Stderr)
-		os.Exit(1)
-	}
-	oldText = args[argi]
-	newText = args[argi+1]
-
-	argi += 2
-
-	*pargi = argi
-	if !doConstruct { // All transformers must do this for main command-line parsing
-		return nil
-	}
-
-	transformer, err := NewTransformerGsub(
-		fieldNames,
-		oldText,
-		newText,
-	)
-	if err != nil {
-		fmt.Fprintln(os.Stderr, err)
-		os.Exit(1)
-	}
-
-	return transformer
-}
-
-// ----------------------------------------------------------------
-type TransformerGsub struct {
-	fieldNames []string
-	oldText    *mlrval.Mlrval
-	newText    *mlrval.Mlrval
-}
-
-// ----------------------------------------------------------------
-func NewTransformerGsub(
-	fieldNames []string,
-	oldText string,
-	newText string,
-) (*TransformerGsub, error) {
-	tr := &TransformerGsub{
-		fieldNames: fieldNames,
-		oldText:    mlrval.FromString(oldText),
-		newText:    mlrval.FromString(newText),
-	}
-	return tr, nil
-}
-
-func (tr *TransformerGsub) Transform(
-	inrecAndContext *types.RecordAndContext,
-	outputRecordsAndContexts *list.List, // list of *types.RecordAndContext
-	inputDownstreamDoneChannel <-chan bool,
-	outputDownstreamDoneChannel chan<- bool,
-) {
-	HandleDefaultDownstreamDone(inputDownstreamDoneChannel, outputDownstreamDoneChannel)
-
-	if !inrecAndContext.EndOfStream {
-		inrec := inrecAndContext.Record
-
-		for _, fieldName := range tr.fieldNames {
-			oldValue := inrec.Get(fieldName)
-			if oldValue == nil {
-				continue
-			}
-
-			newValue := bifs.BIF_gsub(oldValue, tr.oldText, tr.newText)
-
-			inrec.PutReference(fieldName, newValue)
-		}
-
-		outputRecordsAndContexts.PushBack(inrecAndContext)
-	} else {
-		outputRecordsAndContexts.PushBack(inrecAndContext) // emit end-of-stream marker
-	}
-}
diff --git a/pkg/transformers/ssub.go b/pkg/transformers/ssub.go
deleted file mode 100644
index a31864711..000000000
--- a/pkg/transformers/ssub.go
+++ /dev/null
@@ -1,156 +0,0 @@
-package transformers
-
-import (
-	"container/list"
-	"fmt"
-	"os"
-	"strings"
-
-	"github.com/johnkerl/miller/pkg/bifs"
-	"github.com/johnkerl/miller/pkg/cli"
-	"github.com/johnkerl/miller/pkg/mlrval"
-	"github.com/johnkerl/miller/pkg/types"
-)
-
-// ----------------------------------------------------------------
-const verbNameSsub = "ssub"
-
-var SsubSetup = TransformerSetup{
-	Verb:         verbNameSsub,
-	UsageFunc:    transformerSsubUsage,
-	ParseCLIFunc: transformerSsubParseCLI,
-	IgnoresInput: false,
-}
-
-func transformerSsubUsage(
-	o *os.File,
-) {
-	fmt.Fprintf(o, "Usage: %s %s [options]\n", "mlr", verbNameSsub)
-	fmt.Fprintf(o, "Replaces old string with new string in specified field(s), without regex support for\n")
-	fmt.Fprintf(o, "the old string, like the `ssub` DSL function. See also the `gsub` and `sub` verbs.\n")
-	fmt.Fprintf(o, "Options:\n")
-	fmt.Fprintf(o, "-f {a,b,c}  Field names to convert.\n")
-	fmt.Fprintf(o, "-h|--help   Show this message.\n")
-}
-
-func transformerSsubParseCLI(
-	pargi *int,
-	argc int,
-	args []string,
-	_ *cli.TOptions,
-	doConstruct bool, // false for first pass of CLI-parse, true for second pass
-) IRecordTransformer {
-
-	// Skip the verb name from the current spot in the mlr command line
-	argi := *pargi
-	verb := args[argi]
-	argi++
-
-	// Parse local flags
-	var fieldNames []string = nil
-	var oldText string
-	var newText string
-
-	for argi < argc /* variable increment: 1 or 2 depending on flag */ {
-		opt := args[argi]
-		if !strings.HasPrefix(opt, "-") {
-			break // No more flag options to process
-		}
-		if args[argi] == "--" {
-			break // All transformers must do this so main-flags can follow verb-flags
-		}
-		argi++
-
-		if opt == "-h" || opt == "--help" {
-			transformerSsubUsage(os.Stdout)
-			os.Exit(0)
-
-		} else if opt == "-f" {
-			fieldNames = cli.VerbGetStringArrayArgOrDie(verb, opt, args, &argi, argc)
-		} else {
-			transformerSsubUsage(os.Stderr)
-			os.Exit(1)
-		}
-	}
-
-	if fieldNames == nil {
-		transformerSsubUsage(os.Stderr)
-		os.Exit(1)
-	}
-
-	// Get the old and new text from the command line
-	if (argc - argi) < 2 {
-		transformerSsubUsage(os.Stderr)
-		os.Exit(1)
-	}
-	oldText = args[argi]
-	newText = args[argi+1]
-
-	argi += 2
-
-	*pargi = argi
-	if !doConstruct { // All transformers must do this for main command-line parsing
-		return nil
-	}
-
-	transformer, err := NewTransformerSsub(
-		fieldNames,
-		oldText,
-		newText,
-	)
-	if err != nil {
-		fmt.Fprintln(os.Stderr, err)
-		os.Exit(1)
-	}
-
-	return transformer
-}
-
-// ----------------------------------------------------------------
-type TransformerSsub struct {
-	fieldNames []string
-	oldText    *mlrval.Mlrval
-	newText    *mlrval.Mlrval
-}
-
-// ----------------------------------------------------------------
-func NewTransformerSsub(
-	fieldNames []string,
-	oldText string,
-	newText string,
-) (*TransformerSsub, error) {
-	tr := &TransformerSsub{
-		fieldNames: fieldNames,
-		oldText:    mlrval.FromString(oldText),
-		newText:    mlrval.FromString(newText),
-	}
-	return tr, nil
-}
-
-func (tr *TransformerSsub) Transform(
-	inrecAndContext *types.RecordAndContext,
-	outputRecordsAndContexts *list.List, // list of *types.RecordAndContext
-	inputDownstreamDoneChannel <-chan bool,
-	outputDownstreamDoneChannel chan<- bool,
-) {
-	HandleDefaultDownstreamDone(inputDownstreamDoneChannel, outputDownstreamDoneChannel)
-
-	if !inrecAndContext.EndOfStream {
-		inrec := inrecAndContext.Record
-
-		for _, fieldName := range tr.fieldNames {
-			oldValue := inrec.Get(fieldName)
-			if oldValue == nil {
-				continue
-			}
-
-			newValue := bifs.BIF_ssub(oldValue, tr.oldText, tr.newText)
-
-			inrec.PutReference(fieldName, newValue)
-		}
-
-		outputRecordsAndContexts.PushBack(inrecAndContext)
-	} else {
-		outputRecordsAndContexts.PushBack(inrecAndContext) // emit end-of-stream marker
-	}
-}
diff --git a/pkg/transformers/sub.go b/pkg/transformers/sub.go
deleted file mode 100644
index 1c96b45fc..000000000
--- a/pkg/transformers/sub.go
+++ /dev/null
@@ -1,157 +0,0 @@
-package transformers
-
-import (
-	"container/list"
-	"fmt"
-	"os"
-	"strings"
-
-	"github.com/johnkerl/miller/pkg/bifs"
-	"github.com/johnkerl/miller/pkg/cli"
-	"github.com/johnkerl/miller/pkg/mlrval"
-	"github.com/johnkerl/miller/pkg/types"
-)
-
-// ----------------------------------------------------------------
-const verbNameSub = "sub"
-
-var SubSetup = TransformerSetup{
-	Verb:         verbNameSub,
-	UsageFunc:    transformerSubUsage,
-	ParseCLIFunc: transformerSubParseCLI,
-	IgnoresInput: false,
-}
-
-func transformerSubUsage(
-	o *os.File,
-) {
-	fmt.Fprintf(o, "Usage: %s %s [options]\n", "mlr", verbNameSub)
-	fmt.Fprintf(o, "Replaces old string with new string in specified field(s), with regex support\n")
-	fmt.Fprintf(o, "for the old string and not handling multiple matches, like the `sub` DSL function.\n")
-	fmt.Fprintf(o, "See also the `gsub` and `ssub` verbs.\n")
-	fmt.Fprintf(o, "Options:\n")
-	fmt.Fprintf(o, "-f {a,b,c}  Field names to convert.\n")
-	fmt.Fprintf(o, "-h|--help   Show this message.\n")
-}
-
-func transformerSubParseCLI(
-	pargi *int,
-	argc int,
-	args []string,
-	_ *cli.TOptions,
-	doConstruct bool, // false for first pass of CLI-parse, true for second pass
-) IRecordTransformer {
-
-	// Skip the verb name from the current spot in the mlr command line
-	argi := *pargi
-	verb := args[argi]
-	argi++
-
-	// Parse local flags
-	var fieldNames []string = nil
-	var oldText string
-	var newText string
-
-	for argi < argc /* variable increment: 1 or 2 depending on flag */ {
-		opt := args[argi]
-		if !strings.HasPrefix(opt, "-") {
-			break // No more flag options to process
-		}
-		if args[argi] == "--" {
-			break // All transformers must do this so main-flags can follow verb-flags
-		}
-		argi++
-
-		if opt == "-h" || opt == "--help" {
-			transformerSubUsage(os.Stdout)
-			os.Exit(0)
-
-		} else if opt == "-f" {
-			fieldNames = cli.VerbGetStringArrayArgOrDie(verb, opt, args, &argi, argc)
-		} else {
-			transformerSubUsage(os.Stderr)
-			os.Exit(1)
-		}
-	}
-
-	if fieldNames == nil {
-		transformerSubUsage(os.Stderr)
-		os.Exit(1)
-	}
-
-	// Get the old and new text from the command line
-	if (argc - argi) < 2 {
-		transformerSubUsage(os.Stderr)
-		os.Exit(1)
-	}
-	oldText = args[argi]
-	newText = args[argi+1]
-
-	argi += 2
-
-	*pargi = argi
-	if !doConstruct { // All transformers must do this for main command-line parsing
-		return nil
-	}
-
-	transformer, err := NewTransformerSub(
-		fieldNames,
-		oldText,
-		newText,
-	)
-	if err != nil {
-		fmt.Fprintln(os.Stderr, err)
-		os.Exit(1)
-	}
-
-	return transformer
-}
-
-// ----------------------------------------------------------------
-type TransformerSub struct {
-	fieldNames []string
-	oldText    *mlrval.Mlrval
-	newText    *mlrval.Mlrval
-}
-
-// ----------------------------------------------------------------
-func NewTransformerSub(
-	fieldNames []string,
-	oldText string,
-	newText string,
-) (*TransformerSub, error) {
-	tr := &TransformerSub{
-		fieldNames: fieldNames,
-		oldText:    mlrval.FromString(oldText),
-		newText:    mlrval.FromString(newText),
-	}
-	return tr, nil
-}
-
-func (tr *TransformerSub) Transform(
-	inrecAndContext *types.RecordAndContext,
-	outputRecordsAndContexts *list.List, // list of *types.RecordAndContext
-	inputDownstreamDoneChannel <-chan bool,
-	outputDownstreamDoneChannel chan<- bool,
-) {
-	HandleDefaultDownstreamDone(inputDownstreamDoneChannel, outputDownstreamDoneChannel)
-
-	if !inrecAndContext.EndOfStream {
-		inrec := inrecAndContext.Record
-
-		for _, fieldName := range tr.fieldNames {
-			oldValue := inrec.Get(fieldName)
-			if oldValue == nil {
-				continue
-			}
-
-			newValue := bifs.BIF_sub(oldValue, tr.oldText, tr.newText)
-
-			inrec.PutReference(fieldName, newValue)
-		}
-
-		outputRecordsAndContexts.PushBack(inrecAndContext)
-	} else {
-		outputRecordsAndContexts.PushBack(inrecAndContext) // emit end-of-stream marker
-	}
-}
diff --git a/pkg/transformers/subs.go b/pkg/transformers/subs.go
new file mode 100644
index 000000000..e57469d91
--- /dev/null
+++ b/pkg/transformers/subs.go
@@ -0,0 +1,355 @@
+package transformers
+
+import (
+	"container/list"
+	"fmt"
+	"os"
+	"regexp"
+	"strings"
+
+	"github.com/johnkerl/miller/pkg/bifs"
+	"github.com/johnkerl/miller/pkg/cli"
+	"github.com/johnkerl/miller/pkg/lib"
+	"github.com/johnkerl/miller/pkg/mlrval"
+	"github.com/johnkerl/miller/pkg/types"
+)
+
+// ----------------------------------------------------------------
+const verbNameSub = "sub"
+const verbNameGsub = "gsub"
+const verbNameSsub = "ssub"
+
+var SubSetup = TransformerSetup{
+	Verb:         verbNameSub,
+	UsageFunc:    transformerSubUsage,
+	ParseCLIFunc: transformerSubParseCLI,
+	IgnoresInput: false,
+}
+
+var GsubSetup = TransformerSetup{
+	Verb:         verbNameGsub,
+	UsageFunc:    transformerGsubUsage,
+	ParseCLIFunc: transformerGsubParseCLI,
+	IgnoresInput: false,
+}
+
+var SsubSetup = TransformerSetup{
+	Verb:         verbNameSsub,
+	UsageFunc:    transformerSsubUsage,
+	ParseCLIFunc: transformerSsubParseCLI,
+	IgnoresInput: false,
+}
+
+func transformerSubUsage(
+	o *os.File,
+) {
+	fmt.Fprintf(o, "Usage: %s %s [options]\n", "mlr", verbNameSub)
+	fmt.Fprintf(o, "Replaces old string with new string in specified field(s), with regex support\n")
+	fmt.Fprintf(o, "for the old string and not handling multiple matches, like the `sub` DSL function.\n")
+	fmt.Fprintf(o, "See also the `gsub` and `ssub` verbs.\n")
+	fmt.Fprintf(o, "Options:\n")
+	fmt.Fprintf(o, "-f {a,b,c}  Field names to convert.\n")
+	fmt.Fprintf(o, "-h|--help   Show this message.\n")
+}
+
+func transformerGsubUsage(
+	o *os.File,
+) {
+	fmt.Fprintf(o, "Usage: %s %s [options]\n", "mlr", verbNameGsub)
+	fmt.Fprintf(o, "Replaces old string with new string in specified field(s), with regex support\n")
+	fmt.Fprintf(o, "for the old string and handling multiple matches, like the `gsub` DSL function.\n")
+	fmt.Fprintf(o, "See also the `sub` and `ssub` verbs.\n")
+	fmt.Fprintf(o, "Options:\n")
+	fmt.Fprintf(o, "-f {a,b,c}  Field names to convert.\n")
+	fmt.Fprintf(o, "-h|--help   Show this message.\n")
+}
+
+func transformerSsubUsage(
+	o *os.File,
+) {
+	fmt.Fprintf(o, "Usage: %s %s [options]\n", "mlr", verbNameSsub)
+	fmt.Fprintf(o, "Replaces old string with new string in specified field(s), without regex support for\n")
+	fmt.Fprintf(o, "the old string, like the `ssub` DSL function. See also the `gsub` and `sub` verbs.\n")
+	fmt.Fprintf(o, "Options:\n")
+	fmt.Fprintf(o, "-f {a,b,c}  Field names to convert.\n")
+	fmt.Fprintf(o, "-h|--help   Show this message.\n")
+}
+
+type subConstructorFunc func(
+	fieldNames []string,
+	doAllFieldNames bool,
+	doRegexes bool,
+	oldText string,
+	newText string,
+) (IRecordTransformer, error)
+
+type fieldAcceptorFunc func(
+	fieldName string,
+) bool
+
+func transformerSubParseCLI(
+	pargi *int,
+	argc int,
+	args []string,
+	opts *cli.TOptions,
+	doConstruct bool, // false for first pass of CLI-parse, true for second pass
+) IRecordTransformer {
+	return transformerSubsParseCLI(pargi, argc, args, opts, doConstruct, transformerSubUsage, NewTransformerSub)
+}
+
+func transformerGsubParseCLI(
+	pargi *int,
+	argc int,
+	args []string,
+	opts *cli.TOptions,
+	doConstruct bool, // false for first pass of CLI-parse, true for second pass
+) IRecordTransformer {
+	return transformerSubsParseCLI(pargi, argc, args, opts, doConstruct, transformerGsubUsage, NewTransformerGsub)
+}
+
+func transformerSsubParseCLI(
+	pargi *int,
+	argc int,
+	args []string,
+	opts *cli.TOptions,
+	doConstruct bool, // false for first pass of CLI-parse, true for second pass
+) IRecordTransformer {
+	return transformerSubsParseCLI(pargi, argc, args, opts, doConstruct, transformerSsubUsage, NewTransformerSsub)
+}
+
+// transformerSubsParseCLI is a shared CLI-parser for the sub, gsub, and ssub verbs.
+func transformerSubsParseCLI(
+	pargi *int,
+	argc int,
+	args []string,
+	_ *cli.TOptions,
+	doConstruct bool, // false for first pass of CLI-parse, true for second pass
+	usageFunc TransformerUsageFunc,
+	constructorFunc subConstructorFunc,
+) IRecordTransformer {
+
+	// Skip the verb name from the current spot in the mlr command line
+	argi := *pargi
+	verb := args[argi]
+	argi++
+
+	// Parse local flags
+	var fieldNames []string = nil
+	doAllFieldNames := false
+	doRegexes := false
+	var oldText string
+	var newText string
+
+	for argi < argc /* variable increment: 1 or 2 depending on flag */ {
+		opt := args[argi]
+		if !strings.HasPrefix(opt, "-") {
+			break // No more flag options to process
+		}
+		if args[argi] == "--" {
+			break // All transformers must do this so main-flags can follow verb-flags
+		}
+		argi++
+
+		if opt == "-h" || opt == "--help" {
+			usageFunc(os.Stdout)
+			os.Exit(0)
+
+		} else if opt == "-a" {
+			doAllFieldNames = true
+			doRegexes = false
+			fieldNames = nil
+
+		} else if opt == "-r" {
+			doRegexes = true
+
+		} else if opt == "-f" {
+			fieldNames = cli.VerbGetStringArrayArgOrDie(verb, opt, args, &argi, argc)
+			doAllFieldNames = false
+		} else {
+			usageFunc(os.Stderr)
+			os.Exit(1)
+		}
+	}
+
+	if fieldNames == nil && !doAllFieldNames {
+		usageFunc(os.Stderr)
+		os.Exit(1)
+	}
+
+	// Get the old and new text from the command line
+	if (argc - argi) < 2 {
+		usageFunc(os.Stderr)
+		os.Exit(1)
+	}
+	oldText = args[argi]
+	newText = args[argi+1]
+
+	argi += 2
+
+	*pargi = argi
+	if !doConstruct { // All transformers must do this for main command-line parsing
+		return nil
+	}
+
+	transformer, err := constructorFunc(
+		fieldNames,
+		doAllFieldNames,
+		doRegexes,
+		oldText,
+		newText,
+	)
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+
+	return transformer
+}
+
+type TransformerSubs struct {
+	fieldNamesSet map[string]bool  // for -f
+	regexes       []*regexp.Regexp // for -r
+	oldText       *mlrval.Mlrval
+	newText       *mlrval.Mlrval
+	fieldAcceptor fieldAcceptorFunc // for -f, -r, -a
+	subber        bifs.TernaryFunc  // for sub, gsub, ssub
+}
+
+func NewTransformerSub(
+	fieldNames []string,
+	doAllFieldNames bool,
+	doRegexes bool,
+	oldText string,
+	newText string,
+) (IRecordTransformer, error) {
+	return NewTransformerSubs(fieldNames, doAllFieldNames, doRegexes, oldText, newText, safe_sub)
+}
+
+func NewTransformerGsub(
+	fieldNames []string,
+	doAllFieldNames bool,
+	doRegexes bool,
+	oldText string,
+	newText string,
+) (IRecordTransformer, error) {
+	return NewTransformerSubs(fieldNames, doAllFieldNames, doRegexes, oldText, newText, safe_gsub)
+}
+
+func NewTransformerSsub(
+	fieldNames []string,
+	doAllFieldNames bool,
+	doRegexes bool,
+	oldText string,
+	newText string,
+) (IRecordTransformer, error) {
+	return NewTransformerSubs(fieldNames, doAllFieldNames, doRegexes, oldText, newText, safe_ssub)
+}
+
+func NewTransformerSubs(
+	fieldNames []string,
+	doAllFieldNames bool,
+	doRegexes bool,
+	oldText string,
+	newText string,
+	subber bifs.TernaryFunc,
+) (IRecordTransformer, error) {
+	tr := &TransformerSubs{
+		fieldNamesSet: lib.StringListToSet(fieldNames),
+		oldText:       mlrval.FromString(oldText),
+		newText:       mlrval.FromString(newText),
+		subber:        subber,
+	}
+	if doAllFieldNames {
+		tr.fieldAcceptor = tr.fieldAcceptorAll
+	} else if doRegexes {
+		tr.fieldAcceptor = tr.fieldAcceptorByRegexes
+
+		tr.regexes = make([]*regexp.Regexp, len(fieldNames))
+		for i, regexString := range fieldNames {
+			// Handles "a.*b"i Miller case-insensitive-regex specification
+			regex, err := lib.CompileMillerRegex(regexString)
+			if err != nil {
+				fmt.Fprintf(os.Stderr, "%s %s: cannot compile regex [%s]\n", "mlr", verbNameCut, regexString)
+				os.Exit(1)
+			}
+			tr.regexes[i] = regex
+		}
+	} else {
+		tr.fieldAcceptor = tr.fieldAcceptorByNames
+	}
+	return tr, nil
+}
+
+func (tr *TransformerSubs) Transform(
+	inrecAndContext *types.RecordAndContext,
+	outputRecordsAndContexts *list.List, // list of *types.RecordAndContext
+	inputDownstreamDoneChannel <-chan bool,
+	outputDownstreamDoneChannel chan<- bool,
+) {
+	HandleDefaultDownstreamDone(inputDownstreamDoneChannel, outputDownstreamDoneChannel)
+
+	if !inrecAndContext.EndOfStream {
+		inrec := inrecAndContext.Record
+		// Run sub, gsub, or ssub on the user-specified field names
+		for pe := inrec.Head; pe != nil; pe = pe.Next {
+			if tr.fieldAcceptor(pe.Key) {
+				pe.Value = tr.subber(pe.Value, tr.oldText, tr.newText)
+			}
+		}
+	}
+	// Including emit of end-of-stream marker
+	outputRecordsAndContexts.PushBack(inrecAndContext)
+}
+
+// fieldAcceptorByNames implements -f
+func (tr *TransformerSubs) fieldAcceptorByNames(
+	fieldName string,
+) bool {
+	return tr.fieldNamesSet[fieldName]
+}
+
+// fieldAcceptorByNames implements -r
+func (tr *TransformerSubs) fieldAcceptorByRegexes(
+	fieldName string,
+) bool {
+	for _, regex := range tr.regexes {
+		if regex.MatchString(fieldName) {
+			return true
+		}
+	}
+	return false
+}
+
+// fieldAcceptorByNames implements -a
+func (tr *TransformerSubs) fieldAcceptorAll(
+	fieldName string,
+) bool {
+	return true
+}
+
+// safe_sub implements sub, but doesn't produce error-type on non-string input.
+func safe_sub(input1, input2, input3 *mlrval.Mlrval) *mlrval.Mlrval {
+	if input1.IsString() {
+		return bifs.BIF_sub(input1, input2, input3)
+	} else {
+		return input1
+	}
+}
+
+// safe_gsub implements gsub, but doesn't produce error-type on non-string input.
+func safe_gsub(input1, input2, input3 *mlrval.Mlrval) *mlrval.Mlrval {
+	if input1.IsString() {
+		return bifs.BIF_gsub(input1, input2, input3)
+	} else {
+		return input1
+	}
+}
+
+// safe_ssub implements ssub, but doesn't produce error-type on non-string input.
+func safe_ssub(input1, input2, input3 *mlrval.Mlrval) *mlrval.Mlrval {
+	if input1.IsString() {
+		return bifs.BIF_ssub(input1, input2, input3)
+	} else {
+		return input1
+	}
+}
diff --git a/test/cases/verb-sub-gsub-ssub/0001/cmd b/test/cases/verb-sub-gsub-ssub/0001/cmd
deleted file mode 100644
index 7d4cec775..000000000
--- a/test/cases/verb-sub-gsub-ssub/0001/cmd
+++ /dev/null
@@ -1 +0,0 @@
-mlr --d2p --from test/input/abixy sub  -f a,b e X
diff --git a/test/cases/verb-sub-gsub-ssub/0001/expout b/test/cases/verb-sub-gsub-ssub/0001/expout
deleted file mode 100644
index 917c3f5ed..000000000
--- a/test/cases/verb-sub-gsub-ssub/0001/expout
+++ /dev/null
@@ -1,11 +0,0 @@
-a   b   i  x          y
-pan pan 1  0.34679014 0.72680286
-Xks pan 2  0.75867996 0.52215111
-wyX wyX 3  0.20460331 0.33831853
-Xks wyX 4  0.38139939 0.13418874
-wyX pan 5  0.57328892 0.86362447
-zXe pan 6  0.52712616 0.49322129
-Xks zXe 7  0.61178406 0.18788492
-zXe wyX 8  0.59855401 0.97618139
-hat wyX 9  0.03144188 0.74955076
-pan wyX 10 0.50262601 0.95261836
diff --git a/test/cases/verb-sub-gsub-ssub/0002/cmd b/test/cases/verb-sub-gsub-ssub/0002/cmd
deleted file mode 100644
index f33200891..000000000
--- a/test/cases/verb-sub-gsub-ssub/0002/cmd
+++ /dev/null
@@ -1 +0,0 @@
-mlr --d2p --from test/input/abixy gsub -f a,b e X
diff --git a/test/cases/verb-sub-gsub-ssub/0002/expout b/test/cases/verb-sub-gsub-ssub/0002/expout
deleted file mode 100644
index 49d53727b..000000000
--- a/test/cases/verb-sub-gsub-ssub/0002/expout
+++ /dev/null
@@ -1,11 +0,0 @@
-a   b   i  x          y
-pan pan 1  0.34679014 0.72680286
-Xks pan 2  0.75867996 0.52215111
-wyX wyX 3  0.20460331 0.33831853
-Xks wyX 4  0.38139939 0.13418874
-wyX pan 5  0.57328892 0.86362447
-zXX pan 6  0.52712616 0.49322129
-Xks zXX 7  0.61178406 0.18788492
-zXX wyX 8  0.59855401 0.97618139
-hat wyX 9  0.03144188 0.74955076
-pan wyX 10 0.50262601 0.95261836
diff --git a/test/cases/verb-sub-gsub-ssub/0003/cmd b/test/cases/verb-sub-gsub-ssub/0003/cmd
deleted file mode 100644
index ff6b15c4a..000000000
--- a/test/cases/verb-sub-gsub-ssub/0003/cmd
+++ /dev/null
@@ -1 +0,0 @@
-mlr --d2p --from test/input/abixy sub  -f a,b . X
diff --git a/test/cases/verb-sub-gsub-ssub/0003/expout b/test/cases/verb-sub-gsub-ssub/0003/expout
deleted file mode 100644
index a8b8e8643..000000000
--- a/test/cases/verb-sub-gsub-ssub/0003/expout
+++ /dev/null
@@ -1,11 +0,0 @@
-a   b   i  x          y
-Xan Xan 1  0.34679014 0.72680286
-Xks Xan 2  0.75867996 0.52215111
-Xye Xye 3  0.20460331 0.33831853
-Xks Xye 4  0.38139939 0.13418874
-Xye Xan 5  0.57328892 0.86362447
-Xee Xan 6  0.52712616 0.49322129
-Xks Xee 7  0.61178406 0.18788492
-Xee Xye 8  0.59855401 0.97618139
-Xat Xye 9  0.03144188 0.74955076
-Xan Xye 10 0.50262601 0.95261836
diff --git a/test/cases/verb-sub-gsub-ssub/0004/cmd b/test/cases/verb-sub-gsub-ssub/0004/cmd
deleted file mode 100644
index 8770d578d..000000000
--- a/test/cases/verb-sub-gsub-ssub/0004/cmd
+++ /dev/null
@@ -1 +0,0 @@
-mlr --d2p --from test/input/abixy ssub -f a,b e X
diff --git a/test/cases/verb-sub-gsub-ssub/0004/expout b/test/cases/verb-sub-gsub-ssub/0004/expout
deleted file mode 100644
index 917c3f5ed..000000000
--- a/test/cases/verb-sub-gsub-ssub/0004/expout
+++ /dev/null
@@ -1,11 +0,0 @@
-a   b   i  x          y
-pan pan 1  0.34679014 0.72680286
-Xks pan 2  0.75867996 0.52215111
-wyX wyX 3  0.20460331 0.33831853
-Xks wyX 4  0.38139939 0.13418874
-wyX pan 5  0.57328892 0.86362447
-zXe pan 6  0.52712616 0.49322129
-Xks zXe 7  0.61178406 0.18788492
-zXe wyX 8  0.59855401 0.97618139
-hat wyX 9  0.03144188 0.74955076
-pan wyX 10 0.50262601 0.95261836
diff --git a/test/cases/verb-sub-gsub-ssub/gsub-a/cmd b/test/cases/verb-sub-gsub-ssub/gsub-a/cmd
new file mode 100644
index 000000000..21a9e342c
--- /dev/null
+++ b/test/cases/verb-sub-gsub-ssub/gsub-a/cmd
@@ -0,0 +1 @@
+mlr --c2p --from test/input/example.csv gsub -a l X
diff --git a/test/cases/verb-sub-gsub-ssub/0001/experr b/test/cases/verb-sub-gsub-ssub/gsub-a/experr
similarity index 100%
rename from test/cases/verb-sub-gsub-ssub/0001/experr
rename to test/cases/verb-sub-gsub-ssub/gsub-a/experr
diff --git a/test/cases/verb-sub-gsub-ssub/gsub-a/expout b/test/cases/verb-sub-gsub-ssub/gsub-a/expout
new file mode 100644
index 000000000..b75a98d8f
--- /dev/null
+++ b/test/cases/verb-sub-gsub-ssub/gsub-a/expout
@@ -0,0 +1,11 @@
+color  shape    flag  k  index quantity    rate
+yeXXow triangXe true  1  11    43.64980000 9.88700000
+red    square   true  2  15    79.27780000 0.01300000
+red    circXe   true  3  16    13.81030000 2.90100000
+red    square   faXse 4  48    77.55420000 7.46700000
+purpXe triangXe faXse 5  51    81.22900000 8.59100000
+red    square   faXse 6  64    77.19910000 9.53100000
+purpXe triangXe faXse 7  65    80.14050000 5.82400000
+yeXXow circXe   true  8  73    63.97850000 4.23700000
+yeXXow circXe   true  9  87    63.50580000 8.33500000
+purpXe square   faXse 10 91    72.37350000 8.24300000
diff --git a/test/cases/verb-sub-gsub-ssub/gsub-f/cmd b/test/cases/verb-sub-gsub-ssub/gsub-f/cmd
new file mode 100644
index 000000000..a4c3ffc4b
--- /dev/null
+++ b/test/cases/verb-sub-gsub-ssub/gsub-f/cmd
@@ -0,0 +1 @@
+mlr --c2p --from test/input/example.csv gsub -f color,shape,index l X
diff --git a/test/cases/verb-sub-gsub-ssub/0002/experr b/test/cases/verb-sub-gsub-ssub/gsub-f/experr
similarity index 100%
rename from test/cases/verb-sub-gsub-ssub/0002/experr
rename to test/cases/verb-sub-gsub-ssub/gsub-f/experr
diff --git a/test/cases/verb-sub-gsub-ssub/gsub-f/expout b/test/cases/verb-sub-gsub-ssub/gsub-f/expout
new file mode 100644
index 000000000..fda761674
--- /dev/null
+++ b/test/cases/verb-sub-gsub-ssub/gsub-f/expout
@@ -0,0 +1,11 @@
+color  shape    flag  k  index quantity    rate
+yeXXow triangXe true  1  11    43.64980000 9.88700000
+red    square   true  2  15    79.27780000 0.01300000
+red    circXe   true  3  16    13.81030000 2.90100000
+red    square   false 4  48    77.55420000 7.46700000
+purpXe triangXe false 5  51    81.22900000 8.59100000
+red    square   false 6  64    77.19910000 9.53100000
+purpXe triangXe false 7  65    80.14050000 5.82400000
+yeXXow circXe   true  8  73    63.97850000 4.23700000
+yeXXow circXe   true  9  87    63.50580000 8.33500000
+purpXe square   false 10 91    72.37350000 8.24300000
diff --git a/test/cases/verb-sub-gsub-ssub/non-windows/gsub-r/cmd b/test/cases/verb-sub-gsub-ssub/non-windows/gsub-r/cmd
new file mode 100644
index 000000000..14c697154
--- /dev/null
+++ b/test/cases/verb-sub-gsub-ssub/non-windows/gsub-r/cmd
@@ -0,0 +1 @@
+mlr --c2p --from test/input/example.csv gsub -r -f '.*e' l X
diff --git a/test/cases/verb-sub-gsub-ssub/0003/experr b/test/cases/verb-sub-gsub-ssub/non-windows/gsub-r/experr
similarity index 100%
rename from test/cases/verb-sub-gsub-ssub/0003/experr
rename to test/cases/verb-sub-gsub-ssub/non-windows/gsub-r/experr
diff --git a/test/cases/verb-sub-gsub-ssub/non-windows/gsub-r/expout b/test/cases/verb-sub-gsub-ssub/non-windows/gsub-r/expout
new file mode 100644
index 000000000..93b24ea0c
--- /dev/null
+++ b/test/cases/verb-sub-gsub-ssub/non-windows/gsub-r/expout
@@ -0,0 +1,11 @@
+color  shape    flag  k  index quantity    rate
+yellow triangXe true  1  11    43.64980000 9.88700000
+red    square   true  2  15    79.27780000 0.01300000
+red    circXe   true  3  16    13.81030000 2.90100000
+red    square   false 4  48    77.55420000 7.46700000
+purple triangXe false 5  51    81.22900000 8.59100000
+red    square   false 6  64    77.19910000 9.53100000
+purple triangXe false 7  65    80.14050000 5.82400000
+yellow circXe   true  8  73    63.97850000 4.23700000
+yellow circXe   true  9  87    63.50580000 8.33500000
+purple square   false 10 91    72.37350000 8.24300000
diff --git a/test/cases/verb-sub-gsub-ssub/non-windows/ssub-r/cmd b/test/cases/verb-sub-gsub-ssub/non-windows/ssub-r/cmd
new file mode 100644
index 000000000..f6cf74d5e
--- /dev/null
+++ b/test/cases/verb-sub-gsub-ssub/non-windows/ssub-r/cmd
@@ -0,0 +1 @@
+mlr --c2p --from test/input/example.csv ssub -r -f '.*e' l X
diff --git a/test/cases/verb-sub-gsub-ssub/0004/experr b/test/cases/verb-sub-gsub-ssub/non-windows/ssub-r/experr
similarity index 100%
rename from test/cases/verb-sub-gsub-ssub/0004/experr
rename to test/cases/verb-sub-gsub-ssub/non-windows/ssub-r/experr
diff --git a/test/cases/verb-sub-gsub-ssub/non-windows/ssub-r/expout b/test/cases/verb-sub-gsub-ssub/non-windows/ssub-r/expout
new file mode 100644
index 000000000..93b24ea0c
--- /dev/null
+++ b/test/cases/verb-sub-gsub-ssub/non-windows/ssub-r/expout
@@ -0,0 +1,11 @@
+color  shape    flag  k  index quantity    rate
+yellow triangXe true  1  11    43.64980000 9.88700000
+red    square   true  2  15    79.27780000 0.01300000
+red    circXe   true  3  16    13.81030000 2.90100000
+red    square   false 4  48    77.55420000 7.46700000
+purple triangXe false 5  51    81.22900000 8.59100000
+red    square   false 6  64    77.19910000 9.53100000
+purple triangXe false 7  65    80.14050000 5.82400000
+yellow circXe   true  8  73    63.97850000 4.23700000
+yellow circXe   true  9  87    63.50580000 8.33500000
+purple square   false 10 91    72.37350000 8.24300000
diff --git a/test/cases/verb-sub-gsub-ssub/non-windows/sub-r/cmd b/test/cases/verb-sub-gsub-ssub/non-windows/sub-r/cmd
new file mode 100644
index 000000000..cae049e51
--- /dev/null
+++ b/test/cases/verb-sub-gsub-ssub/non-windows/sub-r/cmd
@@ -0,0 +1 @@
+mlr --c2p --from test/input/example.csv sub -r -f '.*e' l X
diff --git a/test/cases/verb-sub-gsub-ssub/non-windows/sub-r/experr b/test/cases/verb-sub-gsub-ssub/non-windows/sub-r/experr
new file mode 100644
index 000000000..e69de29bb
diff --git a/test/cases/verb-sub-gsub-ssub/non-windows/sub-r/expout b/test/cases/verb-sub-gsub-ssub/non-windows/sub-r/expout
new file mode 100644
index 000000000..93b24ea0c
--- /dev/null
+++ b/test/cases/verb-sub-gsub-ssub/non-windows/sub-r/expout
@@ -0,0 +1,11 @@
+color  shape    flag  k  index quantity    rate
+yellow triangXe true  1  11    43.64980000 9.88700000
+red    square   true  2  15    79.27780000 0.01300000
+red    circXe   true  3  16    13.81030000 2.90100000
+red    square   false 4  48    77.55420000 7.46700000
+purple triangXe false 5  51    81.22900000 8.59100000
+red    square   false 6  64    77.19910000 9.53100000
+purple triangXe false 7  65    80.14050000 5.82400000
+yellow circXe   true  8  73    63.97850000 4.23700000
+yellow circXe   true  9  87    63.50580000 8.33500000
+purple square   false 10 91    72.37350000 8.24300000
diff --git a/test/cases/verb-sub-gsub-ssub/ssub-a/cmd b/test/cases/verb-sub-gsub-ssub/ssub-a/cmd
new file mode 100644
index 000000000..f0af9a1c9
--- /dev/null
+++ b/test/cases/verb-sub-gsub-ssub/ssub-a/cmd
@@ -0,0 +1 @@
+mlr --c2p --from test/input/example.csv ssub -a l X
diff --git a/test/cases/verb-sub-gsub-ssub/ssub-a/experr b/test/cases/verb-sub-gsub-ssub/ssub-a/experr
new file mode 100644
index 000000000..e69de29bb
diff --git a/test/cases/verb-sub-gsub-ssub/ssub-a/expout b/test/cases/verb-sub-gsub-ssub/ssub-a/expout
new file mode 100644
index 000000000..643a0290f
--- /dev/null
+++ b/test/cases/verb-sub-gsub-ssub/ssub-a/expout
@@ -0,0 +1,11 @@
+color  shape    flag  k  index quantity    rate
+yeXlow triangXe true  1  11    43.64980000 9.88700000
+red    square   true  2  15    79.27780000 0.01300000
+red    circXe   true  3  16    13.81030000 2.90100000
+red    square   faXse 4  48    77.55420000 7.46700000
+purpXe triangXe faXse 5  51    81.22900000 8.59100000
+red    square   faXse 6  64    77.19910000 9.53100000
+purpXe triangXe faXse 7  65    80.14050000 5.82400000
+yeXlow circXe   true  8  73    63.97850000 4.23700000
+yeXlow circXe   true  9  87    63.50580000 8.33500000
+purpXe square   faXse 10 91    72.37350000 8.24300000
diff --git a/test/cases/verb-sub-gsub-ssub/ssub-f/cmd b/test/cases/verb-sub-gsub-ssub/ssub-f/cmd
new file mode 100644
index 000000000..26b395415
--- /dev/null
+++ b/test/cases/verb-sub-gsub-ssub/ssub-f/cmd
@@ -0,0 +1 @@
+mlr --c2p --from test/input/example.csv ssub -f color,shape,index l X
diff --git a/test/cases/verb-sub-gsub-ssub/ssub-f/experr b/test/cases/verb-sub-gsub-ssub/ssub-f/experr
new file mode 100644
index 000000000..e69de29bb
diff --git a/test/cases/verb-sub-gsub-ssub/ssub-f/expout b/test/cases/verb-sub-gsub-ssub/ssub-f/expout
new file mode 100644
index 000000000..f4bf55be4
--- /dev/null
+++ b/test/cases/verb-sub-gsub-ssub/ssub-f/expout
@@ -0,0 +1,11 @@
+color  shape    flag  k  index quantity    rate
+yeXlow triangXe true  1  11    43.64980000 9.88700000
+red    square   true  2  15    79.27780000 0.01300000
+red    circXe   true  3  16    13.81030000 2.90100000
+red    square   false 4  48    77.55420000 7.46700000
+purpXe triangXe false 5  51    81.22900000 8.59100000
+red    square   false 6  64    77.19910000 9.53100000
+purpXe triangXe false 7  65    80.14050000 5.82400000
+yeXlow circXe   true  8  73    63.97850000 4.23700000
+yeXlow circXe   true  9  87    63.50580000 8.33500000
+purpXe square   false 10 91    72.37350000 8.24300000
diff --git a/test/cases/verb-sub-gsub-ssub/sub-a/cmd b/test/cases/verb-sub-gsub-ssub/sub-a/cmd
new file mode 100644
index 000000000..b0ca748b5
--- /dev/null
+++ b/test/cases/verb-sub-gsub-ssub/sub-a/cmd
@@ -0,0 +1 @@
+mlr --c2p --from test/input/example.csv sub -a l X
diff --git a/test/cases/verb-sub-gsub-ssub/sub-a/experr b/test/cases/verb-sub-gsub-ssub/sub-a/experr
new file mode 100644
index 000000000..e69de29bb
diff --git a/test/cases/verb-sub-gsub-ssub/sub-a/expout b/test/cases/verb-sub-gsub-ssub/sub-a/expout
new file mode 100644
index 000000000..643a0290f
--- /dev/null
+++ b/test/cases/verb-sub-gsub-ssub/sub-a/expout
@@ -0,0 +1,11 @@
+color  shape    flag  k  index quantity    rate
+yeXlow triangXe true  1  11    43.64980000 9.88700000
+red    square   true  2  15    79.27780000 0.01300000
+red    circXe   true  3  16    13.81030000 2.90100000
+red    square   faXse 4  48    77.55420000 7.46700000
+purpXe triangXe faXse 5  51    81.22900000 8.59100000
+red    square   faXse 6  64    77.19910000 9.53100000
+purpXe triangXe faXse 7  65    80.14050000 5.82400000
+yeXlow circXe   true  8  73    63.97850000 4.23700000
+yeXlow circXe   true  9  87    63.50580000 8.33500000
+purpXe square   faXse 10 91    72.37350000 8.24300000
diff --git a/test/cases/verb-sub-gsub-ssub/sub-f-2/cmd b/test/cases/verb-sub-gsub-ssub/sub-f-2/cmd
new file mode 100644
index 000000000..8d5de9b90
--- /dev/null
+++ b/test/cases/verb-sub-gsub-ssub/sub-f-2/cmd
@@ -0,0 +1 @@
+mlr --c2p --from test/input/example.csv sub  -f a,b l X
diff --git a/test/cases/verb-sub-gsub-ssub/sub-f-2/experr b/test/cases/verb-sub-gsub-ssub/sub-f-2/experr
new file mode 100644
index 000000000..e69de29bb
diff --git a/test/cases/verb-sub-gsub-ssub/sub-f-2/expout b/test/cases/verb-sub-gsub-ssub/sub-f-2/expout
new file mode 100644
index 000000000..c3c56133c
--- /dev/null
+++ b/test/cases/verb-sub-gsub-ssub/sub-f-2/expout
@@ -0,0 +1,11 @@
+color  shape    flag  k  index quantity    rate
+yellow triangle true  1  11    43.64980000 9.88700000
+red    square   true  2  15    79.27780000 0.01300000
+red    circle   true  3  16    13.81030000 2.90100000
+red    square   false 4  48    77.55420000 7.46700000
+purple triangle false 5  51    81.22900000 8.59100000
+red    square   false 6  64    77.19910000 9.53100000
+purple triangle false 7  65    80.14050000 5.82400000
+yellow circle   true  8  73    63.97850000 4.23700000
+yellow circle   true  9  87    63.50580000 8.33500000
+purple square   false 10 91    72.37350000 8.24300000
diff --git a/test/cases/verb-sub-gsub-ssub/sub-f/cmd b/test/cases/verb-sub-gsub-ssub/sub-f/cmd
new file mode 100644
index 000000000..605605ad0
--- /dev/null
+++ b/test/cases/verb-sub-gsub-ssub/sub-f/cmd
@@ -0,0 +1 @@
+mlr --c2p --from test/input/example.csv sub  -f color,shape,index l X
diff --git a/test/cases/verb-sub-gsub-ssub/sub-f/experr b/test/cases/verb-sub-gsub-ssub/sub-f/experr
new file mode 100644
index 000000000..e69de29bb
diff --git a/test/cases/verb-sub-gsub-ssub/sub-f/expout b/test/cases/verb-sub-gsub-ssub/sub-f/expout
new file mode 100644
index 000000000..f4bf55be4
--- /dev/null
+++ b/test/cases/verb-sub-gsub-ssub/sub-f/expout
@@ -0,0 +1,11 @@
+color  shape    flag  k  index quantity    rate
+yeXlow triangXe true  1  11    43.64980000 9.88700000
+red    square   true  2  15    79.27780000 0.01300000
+red    circXe   true  3  16    13.81030000 2.90100000
+red    square   false 4  48    77.55420000 7.46700000
+purpXe triangXe false 5  51    81.22900000 8.59100000
+red    square   false 6  64    77.19910000 9.53100000
+purpXe triangXe false 7  65    80.14050000 5.82400000
+yeXlow circXe   true  8  73    63.97850000 4.23700000
+yeXlow circXe   true  9  87    63.50580000 8.33500000
+purpXe square   false 10 91    72.37350000 8.24300000