From 1711929c3364f0049b738a16aabc78521535a2c4 Mon Sep 17 00:00:00 2001
From: John Kerl <kerl.john.r@gmail.com>
Date: Sat, 19 Aug 2023 16:15:36 -0400
Subject: [PATCH 1/4] sub, gsub, and ssub verbs

---
 .../pkg/transformers/aaa_transformer_table.go |   3 +
 internal/pkg/transformers/gsub.go             | 157 ++++++++++++++++++
 internal/pkg/transformers/ssub.go             | 156 +++++++++++++++++
 internal/pkg/transformers/sub.go              | 157 ++++++++++++++++++
 test/cases/cli-help/0001/expout               |  29 ++++
 test/cases/verb-case/x                        |  13 --
 6 files changed, 502 insertions(+), 13 deletions(-)
 create mode 100644 internal/pkg/transformers/gsub.go
 create mode 100644 internal/pkg/transformers/ssub.go
 create mode 100644 internal/pkg/transformers/sub.go
 delete mode 100644 test/cases/verb-case/x

diff --git a/internal/pkg/transformers/aaa_transformer_table.go b/internal/pkg/transformers/aaa_transformer_table.go
index 60f490e0d8..ece90a8584 100644
--- a/internal/pkg/transformers/aaa_transformer_table.go
+++ b/internal/pkg/transformers/aaa_transformer_table.go
@@ -33,6 +33,7 @@ var TRANSFORMER_LOOKUP_TABLE = []TransformerSetup{
 	GrepSetup,
 	GroupBySetup,
 	GroupLikeSetup,
+	GsubSetup,
 	HavingFieldsSetup,
 	HeadSetup,
 	HistogramSetup,
@@ -62,9 +63,11 @@ var TRANSFORMER_LOOKUP_TABLE = []TransformerSetup{
 	SortSetup,
 	SortWithinRecordsSetup,
 	SplitSetup,
+	SsubSetup,
 	Stats1Setup,
 	Stats2Setup,
 	StepSetup,
+	SubSetup,
 	SummarySetup,
 	TacSetup,
 	TailSetup,
diff --git a/internal/pkg/transformers/gsub.go b/internal/pkg/transformers/gsub.go
new file mode 100644
index 0000000000..550aeda5af
--- /dev/null
+++ b/internal/pkg/transformers/gsub.go
@@ -0,0 +1,157 @@
+package transformers
+
+import (
+	"container/list"
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/johnkerl/miller/internal/pkg/bifs"
+	"github.com/johnkerl/miller/internal/pkg/cli"
+	"github.com/johnkerl/miller/internal/pkg/mlrval"
+	"github.com/johnkerl/miller/internal/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/internal/pkg/transformers/ssub.go b/internal/pkg/transformers/ssub.go
new file mode 100644
index 0000000000..bd8e542473
--- /dev/null
+++ b/internal/pkg/transformers/ssub.go
@@ -0,0 +1,156 @@
+package transformers
+
+import (
+	"container/list"
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/johnkerl/miller/internal/pkg/bifs"
+	"github.com/johnkerl/miller/internal/pkg/cli"
+	"github.com/johnkerl/miller/internal/pkg/mlrval"
+	"github.com/johnkerl/miller/internal/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/internal/pkg/transformers/sub.go b/internal/pkg/transformers/sub.go
new file mode 100644
index 0000000000..eee7783624
--- /dev/null
+++ b/internal/pkg/transformers/sub.go
@@ -0,0 +1,157 @@
+package transformers
+
+import (
+	"container/list"
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/johnkerl/miller/internal/pkg/bifs"
+	"github.com/johnkerl/miller/internal/pkg/cli"
+	"github.com/johnkerl/miller/internal/pkg/mlrval"
+	"github.com/johnkerl/miller/internal/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/test/cases/cli-help/0001/expout b/test/cases/cli-help/0001/expout
index d6f70fe41a..55efea8ac7 100644
--- a/test/cases/cli-help/0001/expout
+++ b/test/cases/cli-help/0001/expout
@@ -379,6 +379,16 @@ Outputs records in batches having identical field names.
 Options:
 -h|--help Show this message.
 
+================================================================
+gsub
+Usage: mlr gsub [options]
+Replaces old string with new string in specified field(s), with regex support
+for the old string and handling multiple matches, like the `gsub` DSL function.
+See also the `sub` and `ssub` verbs.
+Options:
+-f {a,b,c}  Field names to convert.
+-h|--help   Show this message.
+
 ================================================================
 having-fields
 Usage: mlr having-fields [options]
@@ -1016,6 +1026,15 @@ then there will be split_yellow_triangle.csv, split_yellow_square.csv, etc.
 
 See also the "tee" DSL function which lets you do more ad-hoc customization.
 
+================================================================
+ssub
+Usage: mlr ssub [options]
+Replaces old string with new string in specified field(s), without regex support for
+the old string, like the `ssub` DSL function. See also the `gsub` and `sub` verbs.
+Options:
+-f {a,b,c}  Field names to convert.
+-h|--help   Show this message.
+
 ================================================================
 stats1
 Usage: mlr stats1 [options]
@@ -1156,6 +1175,16 @@ Please see https://miller.readthedocs.io/en/latest/reference-verbs.html#filter o
 https://en.wikipedia.org/wiki/Moving_average#Exponential_moving_average
 for more information on EWMA.
 
+================================================================
+sub
+Usage: mlr sub [options]
+Replaces old string with new string in specified field(s), with regex support
+for the old string and not handling multiple matches, like the `sub` DSL function.
+See also the `gsub` and `ssub` verbs.
+Options:
+-f {a,b,c}  Field names to convert.
+-h|--help   Show this message.
+
 ================================================================
 summary
 Usage: mlr summary [options]
diff --git a/test/cases/verb-case/x b/test/cases/verb-case/x
deleted file mode 100644
index a24cc18bdf..0000000000
--- a/test/cases/verb-case/x
+++ /dev/null
@@ -1,13 +0,0 @@
-mkdir 0020; echo mlr --from test/input.cases-csv --c2j case -u > 0020/cmd
-mkdir 0021; echo mlr --from test/input.cases-csv --c2j case -l > 0021/cmd
-mkdir 0022; echo mlr --from test/input.cases-csv --c2j case -s > 0022/cmd
-mkdir 0023; echo mlr --from test/input.cases-csv --c2j case -t > 0023/cmd
-mkdir 0024; echo mlr --from test/input.cases-csv --c2j case -k -u > 0024/cmd
-mkdir 0025; echo mlr --from test/input.cases-csv --c2j case -k -l > 0025/cmd
-mkdir 0026; echo mlr --from test/input.cases-csv --c2j case -k -s > 0026/cmd
-mkdir 0027; echo mlr --from test/input.cases-csv --c2j case -k -t > 0027/cmd
-mkdir 0028; echo mlr --from test/input.cases-csv --c2j case -v -u > 0028/cmd
-mkdir 0029; echo mlr --from test/input.cases-csv --c2j case -v -l > 0029/cmd
-mkdir 0030; echo mlr --from test/input.cases-csv --c2j case -v -s > 0030/cmd
-mkdir 0031; echo mlr --from test/input.cases-csv --c2j case -v -t > 0031/cmd
-mkdir 0032; echo mlr --from test/input.cases-csv --c2j case -u apple,ball then case -l cat,dog > 0032/cmd

From 2b9505af49cd9539a34bc10e67954bd2d5191974 Mon Sep 17 00:00:00 2001
From: John Kerl <kerl.john.r@gmail.com>
Date: Sat, 19 Aug 2023 16:19:40 -0400
Subject: [PATCH 2/4] doc mods

---
 docs/src/manpage.md  | 39 +++++++++++++++++++++++++-----
 docs/src/manpage.txt | 39 +++++++++++++++++++++++++-----
 man/manpage.txt      | 39 +++++++++++++++++++++++++-----
 man/mlr.1            | 57 +++++++++++++++++++++++++++++++++++++++-----
 4 files changed, 150 insertions(+), 24 deletions(-)

diff --git a/docs/src/manpage.md b/docs/src/manpage.md
index aad8a4f50f..1a9ebea12c 100644
--- a/docs/src/manpage.md
+++ b/docs/src/manpage.md
@@ -194,12 +194,13 @@ MILLER(1)                                                            MILLER(1)
 1mVERB LIST0m
        altkv bar bootstrap case cat check clean-whitespace count-distinct count
        count-similar cut decimate fill-down fill-empty filter flatten format-values
-       fraction gap grep group-by group-like having-fields head histogram json-parse
-       json-stringify join label latin1-to-utf8 least-frequent merge-fields
-       most-frequent nest nothing put regularize remove-empty-columns rename reorder
-       repeat reshape sample sec2gmtdate sec2gmt seqgen shuffle skip-trivial-records
-       sort sort-within-records split stats1 stats2 step summary tac tail tee
-       template top utf8-to-latin1 unflatten uniq unspace unsparsify
+       fraction gap grep group-by group-like gsub having-fields head histogram
+       json-parse json-stringify join label latin1-to-utf8 least-frequent
+       merge-fields most-frequent nest nothing put regularize remove-empty-columns
+       rename reorder repeat reshape sample sec2gmtdate sec2gmt seqgen shuffle
+       skip-trivial-records sort sort-within-records split ssub stats1 stats2 step
+       sub summary tac tail tee template top utf8-to-latin1 unflatten uniq unspace
+       unsparsify
 
 1mFUNCTION LIST0m
        abs acos acosh any append apply arrayify asin asinh asserting_absent
@@ -1245,6 +1246,15 @@ MILLER(1)                                                            MILLER(1)
        Options:
        -h|--help Show this message.
 
+   1mgsub0m
+       Usage: mlr gsub [options]
+       Replaces old string with new string in specified field(s), with regex support
+       for the old string and handling multiple matches, like the `gsub` DSL function.
+       See also the `sub` and `ssub` verbs.
+       Options:
+       -f {a,b,c}  Field names to convert.
+       -h|--help   Show this message.
+
    1mhaving-fields0m
        Usage: mlr having-fields [options]
        Conditionally passes through records depending on each record's field names.
@@ -1853,6 +1863,14 @@ MILLER(1)                                                            MILLER(1)
 
        See also the "tee" DSL function which lets you do more ad-hoc customization.
 
+   1mssub0m
+       Usage: mlr ssub [options]
+       Replaces old string with new string in specified field(s), without regex support for
+       the old string, like the `ssub` DSL function. See also the `gsub` and `sub` verbs.
+       Options:
+       -f {a,b,c}  Field names to convert.
+       -h|--help   Show this message.
+
    1mstats10m
        Usage: mlr stats1 [options]
        Computes univariate statistics for one or more given fields, accumulated across
@@ -1990,6 +2008,15 @@ MILLER(1)                                                            MILLER(1)
        https://en.wikipedia.org/wiki/Moving_average#Exponential_moving_average
        for more information on EWMA.
 
+   1msub0m
+       Usage: mlr sub [options]
+       Replaces old string with new string in specified field(s), with regex support
+       for the old string and not handling multiple matches, like the `sub` DSL function.
+       See also the `gsub` and `ssub` verbs.
+       Options:
+       -f {a,b,c}  Field names to convert.
+       -h|--help   Show this message.
+
    1msummary0m
        Usage: mlr summary [options]
        Show summary statistics about the input data.
diff --git a/docs/src/manpage.txt b/docs/src/manpage.txt
index 1d59128536..7372e3768b 100644
--- a/docs/src/manpage.txt
+++ b/docs/src/manpage.txt
@@ -173,12 +173,13 @@ MILLER(1)                                                            MILLER(1)
 1mVERB LIST0m
        altkv bar bootstrap case cat check clean-whitespace count-distinct count
        count-similar cut decimate fill-down fill-empty filter flatten format-values
-       fraction gap grep group-by group-like having-fields head histogram json-parse
-       json-stringify join label latin1-to-utf8 least-frequent merge-fields
-       most-frequent nest nothing put regularize remove-empty-columns rename reorder
-       repeat reshape sample sec2gmtdate sec2gmt seqgen shuffle skip-trivial-records
-       sort sort-within-records split stats1 stats2 step summary tac tail tee
-       template top utf8-to-latin1 unflatten uniq unspace unsparsify
+       fraction gap grep group-by group-like gsub having-fields head histogram
+       json-parse json-stringify join label latin1-to-utf8 least-frequent
+       merge-fields most-frequent nest nothing put regularize remove-empty-columns
+       rename reorder repeat reshape sample sec2gmtdate sec2gmt seqgen shuffle
+       skip-trivial-records sort sort-within-records split ssub stats1 stats2 step
+       sub summary tac tail tee template top utf8-to-latin1 unflatten uniq unspace
+       unsparsify
 
 1mFUNCTION LIST0m
        abs acos acosh any append apply arrayify asin asinh asserting_absent
@@ -1224,6 +1225,15 @@ MILLER(1)                                                            MILLER(1)
        Options:
        -h|--help Show this message.
 
+   1mgsub0m
+       Usage: mlr gsub [options]
+       Replaces old string with new string in specified field(s), with regex support
+       for the old string and handling multiple matches, like the `gsub` DSL function.
+       See also the `sub` and `ssub` verbs.
+       Options:
+       -f {a,b,c}  Field names to convert.
+       -h|--help   Show this message.
+
    1mhaving-fields0m
        Usage: mlr having-fields [options]
        Conditionally passes through records depending on each record's field names.
@@ -1832,6 +1842,14 @@ MILLER(1)                                                            MILLER(1)
 
        See also the "tee" DSL function which lets you do more ad-hoc customization.
 
+   1mssub0m
+       Usage: mlr ssub [options]
+       Replaces old string with new string in specified field(s), without regex support for
+       the old string, like the `ssub` DSL function. See also the `gsub` and `sub` verbs.
+       Options:
+       -f {a,b,c}  Field names to convert.
+       -h|--help   Show this message.
+
    1mstats10m
        Usage: mlr stats1 [options]
        Computes univariate statistics for one or more given fields, accumulated across
@@ -1969,6 +1987,15 @@ MILLER(1)                                                            MILLER(1)
        https://en.wikipedia.org/wiki/Moving_average#Exponential_moving_average
        for more information on EWMA.
 
+   1msub0m
+       Usage: mlr sub [options]
+       Replaces old string with new string in specified field(s), with regex support
+       for the old string and not handling multiple matches, like the `sub` DSL function.
+       See also the `gsub` and `ssub` verbs.
+       Options:
+       -f {a,b,c}  Field names to convert.
+       -h|--help   Show this message.
+
    1msummary0m
        Usage: mlr summary [options]
        Show summary statistics about the input data.
diff --git a/man/manpage.txt b/man/manpage.txt
index 1d59128536..7372e3768b 100644
--- a/man/manpage.txt
+++ b/man/manpage.txt
@@ -173,12 +173,13 @@ MILLER(1)                                                            MILLER(1)
 1mVERB LIST0m
        altkv bar bootstrap case cat check clean-whitespace count-distinct count
        count-similar cut decimate fill-down fill-empty filter flatten format-values
-       fraction gap grep group-by group-like having-fields head histogram json-parse
-       json-stringify join label latin1-to-utf8 least-frequent merge-fields
-       most-frequent nest nothing put regularize remove-empty-columns rename reorder
-       repeat reshape sample sec2gmtdate sec2gmt seqgen shuffle skip-trivial-records
-       sort sort-within-records split stats1 stats2 step summary tac tail tee
-       template top utf8-to-latin1 unflatten uniq unspace unsparsify
+       fraction gap grep group-by group-like gsub having-fields head histogram
+       json-parse json-stringify join label latin1-to-utf8 least-frequent
+       merge-fields most-frequent nest nothing put regularize remove-empty-columns
+       rename reorder repeat reshape sample sec2gmtdate sec2gmt seqgen shuffle
+       skip-trivial-records sort sort-within-records split ssub stats1 stats2 step
+       sub summary tac tail tee template top utf8-to-latin1 unflatten uniq unspace
+       unsparsify
 
 1mFUNCTION LIST0m
        abs acos acosh any append apply arrayify asin asinh asserting_absent
@@ -1224,6 +1225,15 @@ MILLER(1)                                                            MILLER(1)
        Options:
        -h|--help Show this message.
 
+   1mgsub0m
+       Usage: mlr gsub [options]
+       Replaces old string with new string in specified field(s), with regex support
+       for the old string and handling multiple matches, like the `gsub` DSL function.
+       See also the `sub` and `ssub` verbs.
+       Options:
+       -f {a,b,c}  Field names to convert.
+       -h|--help   Show this message.
+
    1mhaving-fields0m
        Usage: mlr having-fields [options]
        Conditionally passes through records depending on each record's field names.
@@ -1832,6 +1842,14 @@ MILLER(1)                                                            MILLER(1)
 
        See also the "tee" DSL function which lets you do more ad-hoc customization.
 
+   1mssub0m
+       Usage: mlr ssub [options]
+       Replaces old string with new string in specified field(s), without regex support for
+       the old string, like the `ssub` DSL function. See also the `gsub` and `sub` verbs.
+       Options:
+       -f {a,b,c}  Field names to convert.
+       -h|--help   Show this message.
+
    1mstats10m
        Usage: mlr stats1 [options]
        Computes univariate statistics for one or more given fields, accumulated across
@@ -1969,6 +1987,15 @@ MILLER(1)                                                            MILLER(1)
        https://en.wikipedia.org/wiki/Moving_average#Exponential_moving_average
        for more information on EWMA.
 
+   1msub0m
+       Usage: mlr sub [options]
+       Replaces old string with new string in specified field(s), with regex support
+       for the old string and not handling multiple matches, like the `sub` DSL function.
+       See also the `gsub` and `ssub` verbs.
+       Options:
+       -f {a,b,c}  Field names to convert.
+       -h|--help   Show this message.
+
    1msummary0m
        Usage: mlr summary [options]
        Show summary statistics about the input data.
diff --git a/man/mlr.1 b/man/mlr.1
index 583b5dc11f..4e1dc9ca3b 100644
--- a/man/mlr.1
+++ b/man/mlr.1
@@ -214,12 +214,13 @@ for all things with "map" in their names.
 .nf
 altkv bar bootstrap case cat check clean-whitespace count-distinct count
 count-similar cut decimate fill-down fill-empty filter flatten format-values
-fraction gap grep group-by group-like having-fields head histogram json-parse
-json-stringify join label latin1-to-utf8 least-frequent merge-fields
-most-frequent nest nothing put regularize remove-empty-columns rename reorder
-repeat reshape sample sec2gmtdate sec2gmt seqgen shuffle skip-trivial-records
-sort sort-within-records split stats1 stats2 step summary tac tail tee
-template top utf8-to-latin1 unflatten uniq unspace unsparsify
+fraction gap grep group-by group-like gsub having-fields head histogram
+json-parse json-stringify join label latin1-to-utf8 least-frequent
+merge-fields most-frequent nest nothing put regularize remove-empty-columns
+rename reorder repeat reshape sample sec2gmtdate sec2gmt seqgen shuffle
+skip-trivial-records sort sort-within-records split ssub stats1 stats2 step
+sub summary tac tail tee template top utf8-to-latin1 unflatten uniq unspace
+unsparsify
 .fi
 .if n \{\
 .RE
@@ -1529,6 +1530,21 @@ Options:
 .fi
 .if n \{\
 .RE
+.SS "gsub"
+.if n \{\
+.RS 0
+.\}
+.nf
+Usage: mlr gsub [options]
+Replaces old string with new string in specified field(s), with regex support
+for the old string and handling multiple matches, like the `gsub` DSL function.
+See also the `sub` and `ssub` verbs.
+Options:
+-f {a,b,c}  Field names to convert.
+-h|--help   Show this message.
+.fi
+.if n \{\
+.RE
 .SS "having-fields"
 .if n \{\
 .RS 0
@@ -2311,6 +2327,20 @@ See also the "tee" DSL function which lets you do more ad-hoc customization.
 .fi
 .if n \{\
 .RE
+.SS "ssub"
+.if n \{\
+.RS 0
+.\}
+.nf
+Usage: mlr ssub [options]
+Replaces old string with new string in specified field(s), without regex support for
+the old string, like the `ssub` DSL function. See also the `gsub` and `sub` verbs.
+Options:
+-f {a,b,c}  Field names to convert.
+-h|--help   Show this message.
+.fi
+.if n \{\
+.RE
 .SS "stats1"
 .if n \{\
 .RS 0
@@ -2466,6 +2496,21 @@ for more information on EWMA.
 .fi
 .if n \{\
 .RE
+.SS "sub"
+.if n \{\
+.RS 0
+.\}
+.nf
+Usage: mlr sub [options]
+Replaces old string with new string in specified field(s), with regex support
+for the old string and not handling multiple matches, like the `sub` DSL function.
+See also the `gsub` and `ssub` verbs.
+Options:
+-f {a,b,c}  Field names to convert.
+-h|--help   Show this message.
+.fi
+.if n \{\
+.RE
 .SS "summary"
 .if n \{\
 .RS 0

From a84732720613b82da8bb2780fbf261c3e47dbfa6 Mon Sep 17 00:00:00 2001
From: John Kerl <kerl.john.r@gmail.com>
Date: Sat, 19 Aug 2023 16:26:42 -0400
Subject: [PATCH 3/4] content for verbs reference page

---
 docs/src/reference-verbs.md    | 146 +++++++++++++++++++++++++++++++++
 docs/src/reference-verbs.md.in |  42 ++++++++++
 2 files changed, 188 insertions(+)

diff --git a/docs/src/reference-verbs.md b/docs/src/reference-verbs.md
index a9abbcfe56..6e9fbb4780 100644
--- a/docs/src/reference-verbs.md
+++ b/docs/src/reference-verbs.md
@@ -1447,6 +1447,55 @@ record_count resource
 150          /path/to/second/file
 </pre>
 
+## gsub
+
+<pre class="pre-highlight-in-pair">
+<b>mlr gsub -h</b>
+</pre>
+<pre class="pre-non-highlight-in-pair">
+Usage: mlr gsub [options]
+Replaces old string with new string in specified field(s), with regex support
+for the old string and handling multiple matches, like the `gsub` DSL function.
+See also the `sub` and `ssub` verbs.
+Options:
+-f {a,b,c}  Field names to convert.
+-h|--help   Show this message.
+</pre>
+
+<pre class="pre-highlight-in-pair">
+<b>mlr --icsv --opprint --from example.csv cat --filename then sub -f color,shape l X</b>
+</pre>
+<pre class="pre-non-highlight-in-pair">
+filename    color  shape    flag  k  index quantity rate
+example.csv yeXlow triangXe true  1  11    43.6498  9.8870
+example.csv red    square   true  2  15    79.2778  0.0130
+example.csv red    circXe   true  3  16    13.8103  2.9010
+example.csv red    square   false 4  48    77.5542  7.4670
+example.csv purpXe triangXe false 5  51    81.2290  8.5910
+example.csv red    square   false 6  64    77.1991  9.5310
+example.csv purpXe triangXe false 7  65    80.1405  5.8240
+example.csv yeXlow circXe   true  8  73    63.9785  4.2370
+example.csv yeXlow circXe   true  9  87    63.5058  8.3350
+example.csv purpXe square   false 10 91    72.3735  8.2430
+</pre>
+
+<pre class="pre-highlight-in-pair">
+<b>mlr --icsv --opprint --from example.csv cat --filename then gsub -f color,shape l X</b>
+</pre>
+<pre class="pre-non-highlight-in-pair">
+filename    color  shape    flag  k  index quantity rate
+example.csv yeXXow triangXe true  1  11    43.6498  9.8870
+example.csv red    square   true  2  15    79.2778  0.0130
+example.csv red    circXe   true  3  16    13.8103  2.9010
+example.csv red    square   false 4  48    77.5542  7.4670
+example.csv purpXe triangXe false 5  51    81.2290  8.5910
+example.csv red    square   false 6  64    77.1991  9.5310
+example.csv purpXe triangXe false 7  65    80.1405  5.8240
+example.csv yeXXow circXe   true  8  73    63.9785  4.2370
+example.csv yeXXow circXe   true  9  87    63.5058  8.3350
+example.csv purpXe square   false 10 91    72.3735  8.2430
+</pre>
+
 ## having-fields
 
 <pre class="pre-highlight-in-pair">
@@ -3120,6 +3169,54 @@ then there will be split_yellow_triangle.csv, split_yellow_square.csv, etc.
 See also the "tee" DSL function which lets you do more ad-hoc customization.
 </pre>
 
+## ssub
+
+<pre class="pre-highlight-in-pair">
+<b>mlr ssub -h</b>
+</pre>
+<pre class="pre-non-highlight-in-pair">
+Usage: mlr ssub [options]
+Replaces old string with new string in specified field(s), without regex support for
+the old string, like the `ssub` DSL function. See also the `gsub` and `sub` verbs.
+Options:
+-f {a,b,c}  Field names to convert.
+-h|--help   Show this message.
+</pre>
+
+<pre class="pre-highlight-in-pair">
+<b>mlr --icsv --opprint --from example.csv cat --filename then sub -f filename . o</b>
+</pre>
+<pre class="pre-non-highlight-in-pair">
+filename    color  shape    flag  k  index quantity rate
+oxample.csv yellow triangle true  1  11    43.6498  9.8870
+oxample.csv red    square   true  2  15    79.2778  0.0130
+oxample.csv red    circle   true  3  16    13.8103  2.9010
+oxample.csv red    square   false 4  48    77.5542  7.4670
+oxample.csv purple triangle false 5  51    81.2290  8.5910
+oxample.csv red    square   false 6  64    77.1991  9.5310
+oxample.csv purple triangle false 7  65    80.1405  5.8240
+oxample.csv yellow circle   true  8  73    63.9785  4.2370
+oxample.csv yellow circle   true  9  87    63.5058  8.3350
+oxample.csv purple square   false 10 91    72.3735  8.2430
+</pre>
+
+<pre class="pre-highlight-in-pair">
+<b>mlr --icsv --opprint --from example.csv cat --filename then ssub -f filename . o</b>
+</pre>
+<pre class="pre-non-highlight-in-pair">
+filename    color  shape    flag  k  index quantity rate
+exampleocsv yellow triangle true  1  11    43.6498  9.8870
+exampleocsv red    square   true  2  15    79.2778  0.0130
+exampleocsv red    circle   true  3  16    13.8103  2.9010
+exampleocsv red    square   false 4  48    77.5542  7.4670
+exampleocsv purple triangle false 5  51    81.2290  8.5910
+exampleocsv red    square   false 6  64    77.1991  9.5310
+exampleocsv purple triangle false 7  65    80.1405  5.8240
+exampleocsv yellow circle   true  8  73    63.9785  4.2370
+exampleocsv yellow circle   true  9  87    63.5058  8.3350
+exampleocsv purple square   false 10 91    72.3735  8.2430
+</pre>
+
 ## stats1
 
 <pre class="pre-highlight-in-pair">
@@ -3574,6 +3671,55 @@ $ each 10 uptime | mlr -p step -a delta -f 11
 
 </pre>
 
+## sub
+
+<pre class="pre-highlight-in-pair">
+<b>mlr sub -h</b>
+</pre>
+<pre class="pre-non-highlight-in-pair">
+Usage: mlr sub [options]
+Replaces old string with new string in specified field(s), with regex support
+for the old string and not handling multiple matches, like the `sub` DSL function.
+See also the `gsub` and `ssub` verbs.
+Options:
+-f {a,b,c}  Field names to convert.
+-h|--help   Show this message.
+</pre>
+
+<pre class="pre-highlight-in-pair">
+<b>mlr --icsv --opprint --from example.csv cat --filename then sub -f color,shape l X</b>
+</pre>
+<pre class="pre-non-highlight-in-pair">
+filename    color  shape    flag  k  index quantity rate
+example.csv yeXlow triangXe true  1  11    43.6498  9.8870
+example.csv red    square   true  2  15    79.2778  0.0130
+example.csv red    circXe   true  3  16    13.8103  2.9010
+example.csv red    square   false 4  48    77.5542  7.4670
+example.csv purpXe triangXe false 5  51    81.2290  8.5910
+example.csv red    square   false 6  64    77.1991  9.5310
+example.csv purpXe triangXe false 7  65    80.1405  5.8240
+example.csv yeXlow circXe   true  8  73    63.9785  4.2370
+example.csv yeXlow circXe   true  9  87    63.5058  8.3350
+example.csv purpXe square   false 10 91    72.3735  8.2430
+</pre>
+
+<pre class="pre-highlight-in-pair">
+<b>mlr --icsv --opprint --from example.csv cat --filename then gsub -f color,shape l X</b>
+</pre>
+<pre class="pre-non-highlight-in-pair">
+filename    color  shape    flag  k  index quantity rate
+example.csv yeXXow triangXe true  1  11    43.6498  9.8870
+example.csv red    square   true  2  15    79.2778  0.0130
+example.csv red    circXe   true  3  16    13.8103  2.9010
+example.csv red    square   false 4  48    77.5542  7.4670
+example.csv purpXe triangXe false 5  51    81.2290  8.5910
+example.csv red    square   false 6  64    77.1991  9.5310
+example.csv purpXe triangXe false 7  65    80.1405  5.8240
+example.csv yeXXow circXe   true  8  73    63.9785  4.2370
+example.csv yeXXow circXe   true  9  87    63.5058  8.3350
+example.csv purpXe square   false 10 91    72.3735  8.2430
+</pre>
+
 ## summary
 
 <pre class="pre-highlight-in-pair">
diff --git a/docs/src/reference-verbs.md.in b/docs/src/reference-verbs.md.in
index 0ff0bd15dd..44feda3deb 100644
--- a/docs/src/reference-verbs.md.in
+++ b/docs/src/reference-verbs.md.in
@@ -487,6 +487,20 @@ GENMD-RUN-COMMAND
 mlr --opprint group-like data/het.dkvp
 GENMD-EOF
 
+## gsub
+
+GENMD-RUN-COMMAND
+mlr gsub -h
+GENMD-EOF
+
+GENMD-RUN-COMMAND
+mlr --icsv --opprint --from example.csv cat --filename then sub -f color,shape l X
+GENMD-EOF
+
+GENMD-RUN-COMMAND
+mlr --icsv --opprint --from example.csv cat --filename then gsub -f color,shape l X
+GENMD-EOF
+
 ## having-fields
 
 GENMD-RUN-COMMAND
@@ -987,6 +1001,20 @@ GENMD-RUN-COMMAND
 mlr split --help
 GENMD-EOF
 
+## ssub
+
+GENMD-RUN-COMMAND
+mlr ssub -h
+GENMD-EOF
+
+GENMD-RUN-COMMAND
+mlr --icsv --opprint --from example.csv cat --filename then sub -f filename . o
+GENMD-EOF
+
+GENMD-RUN-COMMAND
+mlr --icsv --opprint --from example.csv cat --filename then ssub -f filename . o
+GENMD-EOF
+
 ## stats1
 
 GENMD-RUN-COMMAND
@@ -1095,6 +1123,20 @@ Example deriving uptime-delta from system uptime:
 
 GENMD-INCLUDE-ESCAPED(data/ping-delta-example.txt)
 
+## sub
+
+GENMD-RUN-COMMAND
+mlr sub -h
+GENMD-EOF
+
+GENMD-RUN-COMMAND
+mlr --icsv --opprint --from example.csv cat --filename then sub -f color,shape l X
+GENMD-EOF
+
+GENMD-RUN-COMMAND
+mlr --icsv --opprint --from example.csv cat --filename then gsub -f color,shape l X
+GENMD-EOF
+
 ## summary
 
 GENMD-RUN-COMMAND

From 182b0eb9da1f6d1913b9d2469ae288bc737a99cc Mon Sep 17 00:00:00 2001
From: John Kerl <kerl.john.r@gmail.com>
Date: Sat, 19 Aug 2023 16:39:10 -0400
Subject: [PATCH 4/4] test/cases/verb-sub-gsub-ssub/

---
 test/cases/verb-sub-gsub-ssub/0001/cmd    |  1 +
 test/cases/verb-sub-gsub-ssub/0001/experr |  0
 test/cases/verb-sub-gsub-ssub/0001/expout | 11 +++++++++++
 test/cases/verb-sub-gsub-ssub/0002/cmd    |  1 +
 test/cases/verb-sub-gsub-ssub/0002/experr |  0
 test/cases/verb-sub-gsub-ssub/0002/expout | 11 +++++++++++
 test/cases/verb-sub-gsub-ssub/0003/cmd    |  1 +
 test/cases/verb-sub-gsub-ssub/0003/experr |  0
 test/cases/verb-sub-gsub-ssub/0003/expout | 11 +++++++++++
 test/cases/verb-sub-gsub-ssub/0004/cmd    |  1 +
 test/cases/verb-sub-gsub-ssub/0004/experr |  0
 test/cases/verb-sub-gsub-ssub/0004/expout | 11 +++++++++++
 12 files changed, 48 insertions(+)
 create mode 100644 test/cases/verb-sub-gsub-ssub/0001/cmd
 create mode 100644 test/cases/verb-sub-gsub-ssub/0001/experr
 create mode 100644 test/cases/verb-sub-gsub-ssub/0001/expout
 create mode 100644 test/cases/verb-sub-gsub-ssub/0002/cmd
 create mode 100644 test/cases/verb-sub-gsub-ssub/0002/experr
 create mode 100644 test/cases/verb-sub-gsub-ssub/0002/expout
 create mode 100644 test/cases/verb-sub-gsub-ssub/0003/cmd
 create mode 100644 test/cases/verb-sub-gsub-ssub/0003/experr
 create mode 100644 test/cases/verb-sub-gsub-ssub/0003/expout
 create mode 100644 test/cases/verb-sub-gsub-ssub/0004/cmd
 create mode 100644 test/cases/verb-sub-gsub-ssub/0004/experr
 create mode 100644 test/cases/verb-sub-gsub-ssub/0004/expout

diff --git a/test/cases/verb-sub-gsub-ssub/0001/cmd b/test/cases/verb-sub-gsub-ssub/0001/cmd
new file mode 100644
index 0000000000..7d4cec775c
--- /dev/null
+++ b/test/cases/verb-sub-gsub-ssub/0001/cmd
@@ -0,0 +1 @@
+mlr --d2p --from test/input/abixy sub  -f a,b e X
diff --git a/test/cases/verb-sub-gsub-ssub/0001/experr b/test/cases/verb-sub-gsub-ssub/0001/experr
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/test/cases/verb-sub-gsub-ssub/0001/expout b/test/cases/verb-sub-gsub-ssub/0001/expout
new file mode 100644
index 0000000000..917c3f5ed6
--- /dev/null
+++ b/test/cases/verb-sub-gsub-ssub/0001/expout
@@ -0,0 +1,11 @@
+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
new file mode 100644
index 0000000000..f33200891d
--- /dev/null
+++ b/test/cases/verb-sub-gsub-ssub/0002/cmd
@@ -0,0 +1 @@
+mlr --d2p --from test/input/abixy gsub -f a,b e X
diff --git a/test/cases/verb-sub-gsub-ssub/0002/experr b/test/cases/verb-sub-gsub-ssub/0002/experr
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/test/cases/verb-sub-gsub-ssub/0002/expout b/test/cases/verb-sub-gsub-ssub/0002/expout
new file mode 100644
index 0000000000..49d53727b3
--- /dev/null
+++ b/test/cases/verb-sub-gsub-ssub/0002/expout
@@ -0,0 +1,11 @@
+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
new file mode 100644
index 0000000000..ff6b15c4ac
--- /dev/null
+++ b/test/cases/verb-sub-gsub-ssub/0003/cmd
@@ -0,0 +1 @@
+mlr --d2p --from test/input/abixy sub  -f a,b . X
diff --git a/test/cases/verb-sub-gsub-ssub/0003/experr b/test/cases/verb-sub-gsub-ssub/0003/experr
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/test/cases/verb-sub-gsub-ssub/0003/expout b/test/cases/verb-sub-gsub-ssub/0003/expout
new file mode 100644
index 0000000000..a8b8e86432
--- /dev/null
+++ b/test/cases/verb-sub-gsub-ssub/0003/expout
@@ -0,0 +1,11 @@
+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
new file mode 100644
index 0000000000..8770d578d5
--- /dev/null
+++ b/test/cases/verb-sub-gsub-ssub/0004/cmd
@@ -0,0 +1 @@
+mlr --d2p --from test/input/abixy ssub -f a,b e X
diff --git a/test/cases/verb-sub-gsub-ssub/0004/experr b/test/cases/verb-sub-gsub-ssub/0004/experr
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/test/cases/verb-sub-gsub-ssub/0004/expout b/test/cases/verb-sub-gsub-ssub/0004/expout
new file mode 100644
index 0000000000..917c3f5ed6
--- /dev/null
+++ b/test/cases/verb-sub-gsub-ssub/0004/expout
@@ -0,0 +1,11 @@
+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