diff --git a/expand.go b/expand.go
index e36338e..39c2341 100644
--- a/expand.go
+++ b/expand.go
@@ -128,7 +128,7 @@ func expandDoubleQuoted(input string, vars map[string][]string, expandBackticks
 	return input, len(input)
 }
 
-// Expand a single quoted string starting after a '\''
+// Expand a single quoted string starting after a '\”
 func expandSingleQuoted(input string) (string, int) {
 	j := strings.Index(input, "'")
 	if j < 0 {
@@ -225,33 +225,6 @@ func expandSigil(input string, vars map[string][]string) ([]string, int) {
 	return []string{"$" + input}, len(input)
 }
 
-// Find and expand all sigils.
-func expandSigils(input string, vars map[string][]string) []string {
-	parts := make([]string, 0)
-	expanded := ""
-	for i := 0; i < len(input); {
-		j := strings.IndexRune(input[i:], '$')
-		if j < 0 {
-			expanded += input[i:]
-			break
-		}
-
-		ex, k := expandSigil(input[j+1:], vars)
-		if len(ex) > 0 {
-			ex[0] = expanded + ex[0]
-			expanded = ex[len(ex)-1]
-			parts = append(parts, ex[:len(ex)-1]...)
-		}
-		i = k
-	}
-
-	if len(expanded) > 0 {
-		parts = append(parts, expanded)
-	}
-
-	return parts
-}
-
 // Find and expand all sigils in a recipe, producing a flat string.
 func expandRecipeSigils(input string, vars map[string][]string) string {
 	expanded := ""
diff --git a/go.mod b/go.mod
index 8b27133..d286ece 100644
--- a/go.mod
+++ b/go.mod
@@ -1,10 +1,15 @@
 module github.com/ctSkennerton/mk
 
-go 1.13
+go 1.24
 
 require (
-	github.com/aws/aws-sdk-go v1.35.25
+	github.com/aws/aws-sdk-go v1.55.7
 	github.com/google/go-cmp v0.4.0
-	github.com/mattn/go-isatty v0.0.12
+	github.com/mattn/go-isatty v0.0.20
 	github.com/sanity-io/litter v1.2.0
 )
+
+require (
+	github.com/jmespath/go-jmespath v0.4.0 // indirect
+	golang.org/x/sys v0.33.0 // indirect
+)
diff --git a/go.sum b/go.sum
index b2d1ff2..bf9878d 100644
--- a/go.sum
+++ b/go.sum
@@ -1,5 +1,5 @@
-github.com/aws/aws-sdk-go v1.35.25 h1:0+UC6ZquMOLvYABoz0olShCAe+M9oKllgPfr2hnv9zE=
-github.com/aws/aws-sdk-go v1.35.25/go.mod h1:tlPOdRjfxPBpNIwqDj61rmsnA85v9jc0Ps9+muhnW+k=
+github.com/aws/aws-sdk-go v1.55.7 h1:UJrkFq7es5CShfBwlWAC8DA077vp8PyVbQd3lqLiztE=
+github.com/aws/aws-sdk-go v1.55.7/go.mod h1:eRwEWoyTWFMVYVQzKMNHWP5/RV4xIUGMQfXQHfHkpNU=
 github.com/davecgh/go-spew v0.0.0-20161028175848-04cdfd42973b/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
@@ -7,10 +7,10 @@ github.com/google/go-cmp v0.4.0 h1:xsAVV57WRhGj6kEIi8ReJzQlHHqcBYCElAvkovg3B/4=
 github.com/google/go-cmp v0.4.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/jmespath/go-jmespath v0.4.0 h1:BEgLn5cpjn8UN1mAw4NjwDrS35OdebyEtFe+9YPoQUg=
 github.com/jmespath/go-jmespath v0.4.0/go.mod h1:T8mJZnbsbmF+m6zOOFylbeCJqk5+pHWvzYPziyZiYoo=
+github.com/jmespath/go-jmespath/internal/testify v1.5.1 h1:shLQSRRSCCPj3f2gpwzGwWFoC7ycTf1rcQZHOlsJ6N8=
 github.com/jmespath/go-jmespath/internal/testify v1.5.1/go.mod h1:L3OGu8Wl2/fWfCI6z80xFu9LTZmf1ZRjMHUOPmWr69U=
-github.com/mattn/go-isatty v0.0.12 h1:wuysRhFDzyxgEmMf5xjvJ2M9dZoWAXNNr5LSBS7uHXY=
-github.com/mattn/go-isatty v0.0.12/go.mod h1:cbi8OIDigv2wuxKPP5vlRcQ1OAZbq2CE4Kysco4FUpU=
-github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
+github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
+github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
 github.com/pmezard/go-difflib v0.0.0-20151028094244-d8ed2627bdf0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
@@ -19,17 +19,11 @@ github.com/sanity-io/litter v1.2.0/go.mod h1:JF6pZUFgu2Q0sBZ+HSV35P8TVPI1TTzEwyu
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v0.0.0-20161117074351-18a02ba4a312 h1:UsFdQ3ZmlzS0BqZYGxvYaXvFGUbCmPGy8DM7qWJJiIQ=
 github.com/stretchr/testify v0.0.0-20161117074351-18a02ba4a312/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
-golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
-golang.org/x/net v0.0.0-20200202094626-16171245cfb2 h1:CCH4IOTTfewWjGOlSp+zGcjutRKlBEZQ6wTn8ozI/nI=
-golang.org/x/net v0.0.0-20200202094626-16171245cfb2/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
-golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
-golang.org/x/sys v0.0.0-20200116001909-b77594299b42 h1:vEOn+mP2zCOVzKckCZy6YsCtDblrpj/w7B9nxGNELpg=
-golang.org/x/sys v0.0.0-20200116001909-b77594299b42 h1:vEOn+mP2zCOVzKckCZy6YsCtDblrpj/w7B9nxGNELpg=
-golang.org/x/sys v0.0.0-20200116001909-b77594299b42/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20200116001909-b77594299b42/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg=
-golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.33.0 h1:q3i8TbbEz+JRD9ywIRlyRAQbM0qF7hu24q3teo2hbuw=
+golang.org/x/sys v0.33.0/go.mod h1:BJP2sWEmIv4KK5OTEluFJCKSidICx8ciO85XgH3Ak8k=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v2 v2.2.8 h1:obN1ZagJSUGI0Ek/LBmuj4SNLPfIny3KsKFopxRdj10=
 gopkg.in/yaml.v2 v2.2.8/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
diff --git a/graph.go b/graph.go
index c00cdb9..f6817f7 100644
--- a/graph.go
+++ b/graph.go
@@ -2,7 +2,6 @@ package main
 
 import (
 	"fmt"
-	"io"
 	"log"
 	"net/url"
 	"os"
@@ -41,16 +40,15 @@ type nodeFlag int
 
 const (
 	nodeFlagCycle    nodeFlag = 0x0002
-	nodeFlagReady             = 0x0004
-	nodeFlagProbable          = 0x0100
-	nodeFlagVacuous           = 0x0200
+	nodeFlagReady    nodeFlag = 0x0004
+	nodeFlagProbable nodeFlag = 0x0100
+	nodeFlagVacuous  nodeFlag = 0x0200
 )
 
 // A node in the dependency graph
 type node struct {
 	r         *rule             // rule to be applied
 	name      string            // target name
-	prog      string            // custom program to compare times
 	t         time.Time         // file modification time
 	exists    bool              // does a non-virtual target exist
 	prereqs   []*edge           // prerequisite rules
@@ -103,19 +101,6 @@ func (g *graph) newnode(name string) *node {
 	return u
 }
 
-// Print a graph in graphviz format.
-func (g *graph) visualize(w io.Writer) {
-	fmt.Fprintln(w, "digraph mk {")
-	for t, u := range g.nodes {
-		for i := range u.prereqs {
-			if u.prereqs[i].v != nil {
-				fmt.Fprintf(w, "    \"%s\" -> \"%s\";\n", t, u.prereqs[i].v.name)
-			}
-		}
-	}
-	fmt.Fprintln(w, "}")
-}
-
 // Create a new arc.
 func (u *node) newedge(v *node, r *rule) *edge {
 	e := &edge{v: v, r: r}
@@ -366,7 +351,7 @@ func (g *graph) ambiguous(u *node) {
 // Print a trace of rules, k
 func (g *graph) trace(name string, e *edge) {
 	fmt.Fprintf(os.Stderr, "\t%s", name)
-	for true {
+	for {
 		prereqname := ""
 		if e.v != nil {
 			prereqname = e.v.name
@@ -379,9 +364,7 @@ func (g *graph) trace(name string, e *edge) {
 					continue
 				}
 			}
-			break
-		} else {
-			break
 		}
+		break
 	}
 }
diff --git a/lex.go b/lex.go
index c778cd0..e5bd0ba 100644
--- a/lex.go
+++ b/lex.go
@@ -15,7 +15,7 @@ const nonBareRunes = " \t\n\r\\=:#'\"$"
 
 // Return true if the string contains whitespace only.
 func onlyWhitespace(s string) bool {
-	return strings.IndexAny(s, " \t\r\n") < 0
+	return !strings.ContainsAny(s, " \t\r\n")
 }
 
 const (
@@ -128,7 +128,7 @@ func (l *lexer) next() rune {
 		l.indented = true
 	} else {
 		l.col += 1
-		if strings.IndexRune(" \t", c) < 0 {
+		if !strings.ContainsRune(" \t", c) {
 			l.indented = false
 		}
 	}
@@ -151,27 +151,17 @@ func (l *lexer) emit(typ tokenType) {
 
 // Consume the next run if it is in the given string.
 func (l *lexer) accept(valid string) bool {
-	if strings.IndexRune(valid, l.peek()) >= 0 {
+	if strings.ContainsRune(valid, l.peek()) {
 		l.next()
 		return true
 	}
 	return false
 }
 
-// Skip the next rune if it is in the valid string. Return true if it was
-// skipped.
-func (l *lexer) ignore(valid string) bool {
-	if strings.IndexRune(valid, l.peek()) >= 0 {
-		l.skip()
-		return true
-	}
-	return false
-}
-
 // Consume characters from the valid string until the next is not.
 func (l *lexer) acceptRun(valid string) int {
 	prevpos := l.pos
-	for strings.IndexRune(valid, l.peek()) >= 0 {
+	for strings.ContainsRune(valid, l.peek()) {
 		l.next()
 	}
 	return l.pos - prevpos
@@ -179,7 +169,7 @@ func (l *lexer) acceptRun(valid string) int {
 
 // Accept until something from the given string is encountered.
 func (l *lexer) acceptUntil(invalid string) {
-	for l.pos < len(l.input) && strings.IndexRune(invalid, l.peek()) < 0 {
+	for l.pos < len(l.input) && !strings.ContainsRune(invalid, l.peek()) {
 		l.next()
 	}
 
@@ -191,7 +181,7 @@ func (l *lexer) acceptUntil(invalid string) {
 // Accept until something from the given string is encountered, or the end of th
 // file
 func (l *lexer) acceptUntilOrEof(invalid string) {
-	for l.pos < len(l.input) && strings.IndexRune(invalid, l.peek()) < 0 {
+	for l.pos < len(l.input) && !strings.ContainsRune(invalid, l.peek()) {
 		l.next()
 	}
 }
@@ -199,7 +189,7 @@ func (l *lexer) acceptUntilOrEof(invalid string) {
 // Skip characters from the valid string until the next is not.
 func (l *lexer) skipRun(valid string) int {
 	prevpos := l.pos
-	for strings.IndexRune(valid, l.peek()) >= 0 {
+	for strings.ContainsRune(valid, l.peek()) {
 		l.skip()
 	}
 	return l.pos - prevpos
@@ -207,7 +197,7 @@ func (l *lexer) skipRun(valid string) int {
 
 // Skip until something from the given string is encountered.
 func (l *lexer) skipUntil(invalid string) {
-	for l.pos < len(l.input) && strings.IndexRune(invalid, l.peek()) < 0 {
+	for l.pos < len(l.input) && !strings.ContainsRune(invalid, l.peek()) {
 		l.skip()
 	}
 
diff --git a/mk.go b/mk.go
index cdbfa29..e8d7c3b 100644
--- a/mk.go
+++ b/mk.go
@@ -4,7 +4,6 @@ import (
 	"bufio"
 	"flag"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"runtime"
@@ -107,7 +106,6 @@ const (
 )
 
 // Build a node's prereqs. Block until completed.
-//
 func mkNodePrereqs(g *graph, u *node, e *edge, prereqs []*node, dryrun bool,
 	required bool) nodeStatus {
 	prereqstat := make(chan nodeStatus)
@@ -145,11 +143,11 @@ func mkNodePrereqs(g *graph, u *node, e *edge, prereqs []*node, dryrun bool,
 // concurrently.
 //
 // Args:
-//  g: Graph in which the node lives.
-//  u: Node to (possibly) build.
-//  dryrun: Don't actually build anything, just pretend.
-//  required: Avoid building this node, unless its prereqs are out of date.
 //
+//	g: Graph in which the node lives.
+//	u: Node to (possibly) build.
+//	dryrun: Don't actually build anything, just pretend.
+//	required: Avoid building this node, unless its prereqs are out of date.
 func mkNode(g *graph, u *node, dryrun bool, required bool) {
 	// try to claim on this node
 	u.mutex.Lock()
@@ -270,24 +268,6 @@ func mkPrintError(msg string) {
 	}
 }
 
-func mkPrintSuccess(msg string) {
-	if !color {
-		fmt.Println(msg)
-	} else {
-		fmt.Printf("%s%s%s\n", ansiTermGreen, msg, ansiTermDefault)
-	}
-}
-
-func mkPrintMessage(msg string) {
-	mkMsgMutex.Lock()
-	if !color {
-		fmt.Println(msg)
-	} else {
-		fmt.Printf("%s%s%s\n", ansiTermBlue, msg, ansiTermDefault)
-	}
-	mkMsgMutex.Unlock()
-}
-
 func mkPrintRecipe(target string, recipe string, quiet bool) {
 	mkMsgMutex.Lock()
 	if !color {
@@ -345,12 +325,10 @@ func main() {
 		}
 	}
 
-	mkfile, err := os.Open(mkfilepath)
+	input, err := os.ReadFile(mkfilepath)
 	if err != nil {
 		mkError("no mkfile found")
 	}
-	input, _ := ioutil.ReadAll(mkfile)
-	mkfile.Close()
 
 	abspath, err := filepath.Abs(mkfilepath)
 	if err != nil {
@@ -414,7 +392,7 @@ func main() {
 			c, _, err := in.ReadRune()
 			if err != nil {
 				return
-			} else if strings.IndexRune(" \n\t\r", c) >= 0 {
+			} else if strings.ContainsRune(" \n\t\r", c) {
 				continue
 			} else if c == 'y' {
 				break
diff --git a/mk_test.go b/mk_test.go
index 1117c0b..34717dd 100644
--- a/mk_test.go
+++ b/mk_test.go
@@ -2,7 +2,6 @@ package main
 
 import (
 	"bytes"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"testing"
@@ -147,12 +146,7 @@ func TestBasicMaking(t *testing.T) {
 			}
 		}
 
-		efd, err := os.Open(tv.output)
-		if err != nil {
-			t.Errorf("%s can't open: %v", tv.input, err)
-			continue
-		}
-		want, err := ioutil.ReadAll(efd)
+		want, err := os.ReadFile(tv.output)
 		if err != nil {
 			t.Errorf("%s can't read: %v", tv.input, err)
 			continue
diff --git a/parse.go b/parse.go
index 7e1d8a9..17fdc5d 100644
--- a/parse.go
+++ b/parse.go
@@ -5,7 +5,6 @@ package main
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"regexp"
@@ -175,11 +174,10 @@ func parseRedirInclude(p *parser, t token) parserStateFun {
 		// TODO(rjk): Be sure that this is the right behaviour.
 		filename = parts[0]
 
-		file, err := os.Open(filename)
+		input, err := os.ReadFile(filename)
 		if err != nil {
 			p.basicErrorAtToken(fmt.Sprintf("cannot open %s", filename), p.tokenbuf[0])
 		}
-		input, _ := ioutil.ReadAll(file)
 
 		path, err := filepath.Abs(filename)
 		if err != nil {
diff --git a/recipe.go b/recipe.go
index 1796228..6e23aa2 100644
--- a/recipe.go
+++ b/recipe.go
@@ -25,7 +25,7 @@ func stripIndentation(s string, mincol int) string {
 		i := 0
 		for i < len(line) && col < mincol {
 			c, w := utf8.DecodeRuneInString(line[i:])
-			if strings.IndexRune(" \t\n", c) >= 0 {
+			if strings.ContainsRune(" \t\n", c) {
 				col += 1
 				i += w
 			} else {
@@ -130,16 +130,17 @@ func dorecipe(target string, u *node, e *edge, dryrun bool) bool {
 // Execute a subprocess (typically a recipe).
 //
 // Args:
-//   program: Program path or name located in PATH
-//   input: String piped into the program's stdin
-//   capture_out: If true, capture and return the program's stdout rather than echoing it.
+//
+//	program: Program path or name located in PATH
+//	input: String piped into the program's stdin
+//	capture_out: If true, capture and return the program's stdout rather than echoing it.
 //
 // Returns
-//   (output, success)
-//   output is an empty string of catputer_out is false, or the collected output from the profram is true.
 //
-//   success is true if the exit code was 0 and false otherwise
+//	(output, success)
+//	output is an empty string of catputer_out is false, or the collected output from the profram is true.
 //
+//	success is true if the exit code was 0 and false otherwise
 func subprocess(program string,
 	args []string,
 	env []string,
diff --git a/remote.go b/remote.go
index 03947bd..5d41508 100644
--- a/remote.go
+++ b/remote.go
@@ -1,6 +1,7 @@
 package main
 
 import (
+	"fmt"
 	"log"
 	"net/http"
 	"net/url"
@@ -36,7 +37,11 @@ func updateHttpTimestamp(u *node) {
 }
 
 func updateS3Timestamp(u *node, uri *url.URL) {
-	svc := s3.New(session.New())
+	ses, err := session.NewSession()
+	if err != nil {
+		panic(fmt.Errorf("unable to create a session: %w", err))
+	}
+	svc := s3.New(ses)
 	input := &s3.HeadObjectInput{
 		Bucket: aws.String(uri.Host),
 		Key:    aws.String(uri.Path[1:]),
diff --git a/rules_test.go b/rules_test.go
index 210a700..b833d2d 100644
--- a/rules_test.go
+++ b/rules_test.go
@@ -6,7 +6,7 @@ import (
 )
 
 func TestMatchMetaRule(t *testing.T) {
-	regex, err := regexp.Compile("^data/processed/(\\d+)/mapping_k10.bam.bai$")
+	regex, err := regexp.Compile(`^data/processed/(\d+)/mapping_k10.bam.bai$`)
 	if err != nil {
 		t.Error("Failure to compile regex pattern")
 	}