diff --git a/.github/workflows/go.yml b/.github/workflows/go.yml
index 1c84425..0fe3c59 100644
--- a/.github/workflows/go.yml
+++ b/.github/workflows/go.yml
@@ -23,7 +23,7 @@ jobs:
     - name: Lint
       uses: golangci/golangci-lint-action@v9
       with:
-        version: v2.9
+        version: v2.13
     - name: Spelling
       uses: streetsidesoftware/cspell-action@v8
       continue-on-error: true
diff --git a/examples/http/main.go b/examples/http/main.go
index 3ad4b77..1559465 100644
--- a/examples/http/main.go
+++ b/examples/http/main.go
@@ -12,8 +12,6 @@ import (
 	"syscall"
 	"time"
 
-	"github.com/google/uuid"
-
 	"github.com/brandon1024/cmder"
 	"github.com/brandon1024/cmder/getopt"
 )
@@ -122,7 +120,7 @@ func (c *ServerCommand) Initialize(ctx context.Context, args []string) error {
 	if c.auth && c.basicAuth == "" {
 		var (
 			user = "admin"
-			pass = uuid.New().String()
+			pass = "admin"
 		)
 
 		slog.Info("no credentials configured: using generated basic auth credentials", "user", user, "pass", pass)
@@ -144,6 +142,7 @@ func (c *ServerCommand) Run(ctx context.Context, args []string) error {
 
 	slog.Info("starting web server", "addr", c.addr)
 
+	//nolint:gosec // gosec:disable G118 -- Parent context is cancelled when this shutdown routine executes.
 	go func() {
 		<-ctx.Done()
 
diff --git a/getopt/alias.go b/getopt/alias.go
index c74e7fe..87364c1 100644
--- a/getopt/alias.go
+++ b/getopt/alias.go
@@ -6,7 +6,10 @@ import (
 )
 
 // Alias is a simple utility for registering flag aliases. A new flag is registered in fs with name alias and the
-// [flag.Value] of a flag named name.
+// [flag.Value] of a flag named name. This is functionally equivalent to:
+//
+//	flg := fs.Lookup(name)
+//	fs.Var(flg.Value, alias, flg.Usage)
 //
 // If flag name doesn't exist in fs, panic.
 func Alias(fs *flag.FlagSet, name, alias string) {
diff --git a/getopt/countervar.go b/getopt/countervar.go
index 234f07f..97ec7ef 100644
--- a/getopt/countervar.go
+++ b/getopt/countervar.go
@@ -21,7 +21,7 @@ type CounterVar[T CounterType] struct {
 	value *T
 }
 
-// Counter Initializes a [CounterVar] with an initial value.
+// Counter initializes a [CounterVar] with an initial value.
 func Counter[T CounterType](value *T) *CounterVar[T] {
 	return &CounterVar[T]{
 		value: value,
diff --git a/getopt/example_alias_test.go b/getopt/example_alias_test.go
new file mode 100644
index 0000000..73cf701
--- /dev/null
+++ b/getopt/example_alias_test.go
@@ -0,0 +1,42 @@
+package getopt_test
+
+import (
+	"flag"
+	"fmt"
+	"os"
+
+	"github.com/brandon1024/cmder/getopt"
+)
+
+// This example demonstrates the usage of [getopt.Alias].
+func ExampleAlias() {
+	var (
+		count  uint
+		output string
+	)
+
+	fs := getopt.NewPosixFlagSet("alias", flag.ContinueOnError)
+
+	fs.UintVar(&count, "count", 12, "`number` of results")
+	fs.StringVar(&output, "output", "-", "output `file`")
+
+	getopt.Alias(fs.FlagSet, "count", "c")
+	getopt.Alias(fs.FlagSet, "output", "o")
+
+	fs.SetOutput(os.Stdout)
+	fs.PrintDefaults()
+
+	if err := fs.Parse([]string{"-c", "2025", "-o", "output.txt"}); err != nil {
+		panic(err)
+	}
+
+	fmt.Printf("values: %d %s\n", count, output)
+
+	// Output:
+	//   -c <number>, --count=<number> (default 12)
+	//       number of results
+	//
+	//   -o <file>, --output=<file> (default -)
+	//       output file
+	// values: 2025 output.txt
+}
diff --git a/getopt/example_negatedboolvar_test.go b/getopt/example_negatedboolvar_test.go
index 4f7cc1d..8505a88 100644
--- a/getopt/example_negatedboolvar_test.go
+++ b/getopt/example_negatedboolvar_test.go
@@ -3,6 +3,7 @@ package getopt_test
 import (
 	"flag"
 	"fmt"
+	"os"
 
 	"github.com/brandon1024/cmder/getopt"
 )
@@ -14,7 +15,7 @@ func ExampleNegatedBoolVar() {
 		verify bool
 	)
 
-	fs := flag.NewFlagSet("custom", flag.ContinueOnError)
+	fs := getopt.NewPosixFlagSet("custom", flag.ContinueOnError)
 
 	// option 1: using NegatedBoolVar directly
 	fs.BoolVar(&sign, "gpg-sign", false, "gpg sign the input")
@@ -24,9 +25,12 @@ func ExampleNegatedBoolVar() {
 	fs.BoolVar(&verify, "verify", false, "verify the result")
 	fs.Var(getopt.NegatedBool(&verify), "no-verify", "skip result verification")
 
+	fs.SetOutput(os.Stdout)
+	fs.PrintDefaults()
+
 	args := []string{
-		"-gpg-sign", "-no-gpg-sign",
-		"-no-verify=false",
+		"--gpg-sign", "--no-gpg-sign",
+		"--no-verify=false",
 	}
 
 	if err := fs.Parse(args); err != nil {
@@ -36,6 +40,11 @@ func ExampleNegatedBoolVar() {
 	fmt.Printf("sign: %v\n", sign)
 	fmt.Printf("verify: %v\n", verify)
 	// Output:
+	//   --gpg-sign, --no-gpg-sign
+	//       gpg sign the input
+	//
+	//   --verify, --no-verify
+	//       verify the result
 	// sign: false
 	// verify: true
 }
diff --git a/getopt/flagset.go b/getopt/flagset.go
index d261541..f2b6ab8 100644
--- a/getopt/flagset.go
+++ b/getopt/flagset.go
@@ -448,7 +448,7 @@ func (f *PosixFlagSet) group() map[string][]*flag.Flag {
 		groups[flg.Name] = []*flag.Flag{flg}
 
 		// traverse the flags again and find (and remove) any which match flg
-		for i := len(collected) - 1; i >= 0; i-- {
+		for i := range slices.Backward(collected) {
 			other := collected[i]
 
 			if areSame(flg.Value, other.Value) {
diff --git a/getopt/bool.go b/getopt/negatedboolvar.go
similarity index 100%
rename from getopt/bool.go
rename to getopt/negatedboolvar.go
diff --git a/go.mod b/go.mod
index aa4977c..e2ff530 100644
--- a/go.mod
+++ b/go.mod
@@ -1,33 +1,30 @@
 module github.com/brandon1024/cmder
 
-go 1.25.0
+go 1.26.0
 
-toolchain go1.26.5
+toolchain go1.27.0
 
 tool (
 	golang.org/x/tools/cmd/goimports
 	gotest.tools/gotestsum
 )
 
-require (
-	github.com/google/go-cmp v0.7.0
-	github.com/google/uuid v1.6.0
-)
+require github.com/google/go-cmp v0.7.0
 
 require (
-	github.com/bitfield/gotestdox v0.2.2 // indirect
+	github.com/bitfield/gotestdox v0.2.3 // indirect
 	github.com/dnephin/pflag v1.0.7 // indirect
 	github.com/fatih/color v1.19.0 // indirect
 	github.com/fsnotify/fsnotify v1.10.1 // indirect
 	github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510 // indirect
 	github.com/mattn/go-colorable v0.1.15 // indirect
-	github.com/mattn/go-isatty v0.0.22 // indirect
-	golang.org/x/mod v0.36.0 // indirect
-	golang.org/x/sync v0.20.0 // indirect
-	golang.org/x/sys v0.45.0 // indirect
-	golang.org/x/telemetry v0.0.0-20260527142108-59979362b252 // indirect
-	golang.org/x/term v0.43.0 // indirect
-	golang.org/x/text v0.37.0 // indirect
-	golang.org/x/tools v0.45.0 // indirect
+	github.com/mattn/go-isatty v0.0.24 // indirect
+	golang.org/x/mod v0.40.0 // indirect
+	golang.org/x/sync v0.22.0 // indirect
+	golang.org/x/sys v0.47.0 // indirect
+	golang.org/x/telemetry v0.0.0-20260824150023-1f5465a7b7fb // indirect
+	golang.org/x/term v0.45.0 // indirect
+	golang.org/x/text v0.41.0 // indirect
+	golang.org/x/tools v0.49.0 // indirect
 	gotest.tools/gotestsum v1.13.0 // indirect
 )
diff --git a/go.sum b/go.sum
index 1eca91b..0cbf2b3 100644
--- a/go.sum
+++ b/go.sum
@@ -1,5 +1,5 @@
-github.com/bitfield/gotestdox v0.2.2 h1:x6RcPAbBbErKLnapz1QeAlf3ospg8efBsedU93CDsnE=
-github.com/bitfield/gotestdox v0.2.2/go.mod h1:D+gwtS0urjBrzguAkTM2wodsTQYFHdpx8eqRJ3N+9pY=
+github.com/bitfield/gotestdox v0.2.3 h1:H8Wy07kYacr3YSF5aJON/m9ASE+PGKOSufXkTjqQGb8=
+github.com/bitfield/gotestdox v0.2.3/go.mod h1:bq/HemlNNqEvjOzy7brevVhzZD8WTGFDGq59DOIsHqI=
 github.com/dnephin/pflag v1.0.7 h1:oxONGlWxhmUct0YzKTgrpQv9AUA1wtPBn7zuSjJqptk=
 github.com/dnephin/pflag v1.0.7/go.mod h1:uxE91IoWURlOiTUIA8Mq5ZZkAv3dPUfZNaT80Zm7OQE=
 github.com/fatih/color v1.19.0 h1:Zp3PiM21/9Ld6FzSKyL5c/BULoe/ONr9KlbYVOfG8+w=
@@ -10,28 +10,26 @@ github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
 github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
 github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510 h1:El6M4kTTCOh6aBiKaUGG7oYTSPP8MxqL4YI3kZKwcP4=
 github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510/go.mod h1:pupxD2MaaD3pAXIBCelhxNneeOaAeabZDe5s4K6zSpQ=
-github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
-github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/mattn/go-colorable v0.1.15 h1:+u9SLTRGnXv73cEsnsmoZBom+dMU88B2M0aDcWy0/jY=
 github.com/mattn/go-colorable v0.1.15/go.mod h1:6LmQG8QLFO4G5z1gPvYEzlUgJ2wF+stgPZH1UqBm1s8=
-github.com/mattn/go-isatty v0.0.22 h1:j8l17JJ9i6VGPUFUYoTUKPSgKe/83EYU2zBC7YNKMw4=
-github.com/mattn/go-isatty v0.0.22/go.mod h1:ZXfXG4SQHsB/w3ZeOYbR0PrPwLy+n6xiMrJlRFqopa4=
+github.com/mattn/go-isatty v0.0.24 h1:tGZZoVgT/KiqK1c8ocVLeDS8BSWMRd47J3Lbz7vsReI=
+github.com/mattn/go-isatty v0.0.24/go.mod h1:nMCL3Zebbrt45jsMDgnfIwz6ydEQApk5oEI3HqDio6A=
 github.com/rogpeppe/go-internal v1.11.0 h1:cWPaGQEPrBb5/AsnsZesgZZ9yb1OQ+GOISoDNXVBh4M=
 github.com/rogpeppe/go-internal v1.11.0/go.mod h1:ddIwULY96R17DhadqLgMfk9H9tvdUzkipdSkR5nkCZA=
-golang.org/x/mod v0.36.0 h1:JJjpVx6myfUsUdAzZuOSTTmRE0PfZeNWzzvKrP7amb4=
-golang.org/x/mod v0.36.0/go.mod h1:moc6ELqsWcOw5Ef3xVprK5ul/MvtVvkIXLziUOICjUQ=
-golang.org/x/sync v0.20.0 h1:e0PTpb7pjO8GAtTs2dQ6jYa5BWYlMuX047Dco/pItO4=
-golang.org/x/sync v0.20.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=
-golang.org/x/sys v0.45.0 h1:dO4czNzziLiiXplLQgBCEpCvXQ3dnkn0SdaZSYdQ+FY=
-golang.org/x/sys v0.45.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
-golang.org/x/telemetry v0.0.0-20260527142108-59979362b252 h1:uqWbB1NVuonFfz1UgfdXW1kk6p+3XTFDVGBHOQkfwjg=
-golang.org/x/telemetry v0.0.0-20260527142108-59979362b252/go.mod h1:Eqhaxk/wZsWEH8CRxLwj6xzEJbz7k1EFGqx7nyCoabE=
-golang.org/x/term v0.43.0 h1:S4RLU2sB31O/NCl+zFN9Aru9A/Cq2aqKpTZJ6B+DwT4=
-golang.org/x/term v0.43.0/go.mod h1:lrhlHNdQJHO+1qVYiHfFKVuVioJIheAc3fBSMFYEIsk=
-golang.org/x/text v0.37.0 h1:Cqjiwd9eSg8e0QAkyCaQTNHFIIzWtidPahFWR83rTrc=
-golang.org/x/text v0.37.0/go.mod h1:a5sjxXGs9hsn/AJVwuElvCAo9v8QYLzvavO5z2PiM38=
-golang.org/x/tools v0.45.0 h1:18qN3FAooORvApf5XjCXgsuayZOEtXf6JK18I3+ONa8=
-golang.org/x/tools v0.45.0/go.mod h1:LuUGqqaXcXMEFEruIVJVm5mgDD8vww/z/SR1gQ4uE/0=
+golang.org/x/mod v0.40.0 h1:hUv+3cXcdRHz08UmSiOob7sadHig73uo5bkXxQ/tvUs=
+golang.org/x/mod v0.40.0/go.mod h1:0/weTWkPWGBikyTWAX3dkjVztMmBA5hM0DH6BElSupE=
+golang.org/x/sync v0.22.0 h1:SZjpbeLmrCk4xhRSZFNZW5gFUeCeFgjekvI/+gfScek=
+golang.org/x/sync v0.22.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=
+golang.org/x/sys v0.47.0 h1:o7XGOvZQCADBQQ4Y7VNq2dRWQR7JmOUW8Kxx4ZsNgWs=
+golang.org/x/sys v0.47.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
+golang.org/x/telemetry v0.0.0-20260824150023-1f5465a7b7fb h1:u2wx6smkicd2/as9DfdcyWweWaV7tGvybRQdvPQ74Bw=
+golang.org/x/telemetry v0.0.0-20260824150023-1f5465a7b7fb/go.mod h1:/KSYFnLndIrA1A+Rs5r6vSifQhuFz75BPNN3J/hvzN0=
+golang.org/x/term v0.45.0 h1:NwWyBmoJCbfTHpxrWoZ9C6/VxOf7ic219I8xZZFdrf0=
+golang.org/x/term v0.45.0/go.mod h1:9aqxs0blBcrm/n0L9QW0aRVD+ktan8ssZromtqJC43w=
+golang.org/x/text v0.41.0 h1:vz/seA0lnX87Othu2f/0L24RcgrXD9/YFTSuGjj3rH8=
+golang.org/x/text v0.41.0/go.mod h1:jvf1O8ajNzZqhSrQBPbutR/EB83Cc0CFrezNQIwbb5M=
+golang.org/x/tools v0.49.0 h1:3NI7VXzL9+1WZD52Dx2ttoPwD5DWrFGpl9mFZDlmisI=
+golang.org/x/tools v0.49.0/go.mod h1:SJNXV9DBKT0UbdttsQjbfJlAE/q+y36++zo3uL3N0Oo=
 gotest.tools/gotestsum v1.13.0 h1:+Lh454O9mu9AMG1APV4o0y7oDYKyik/3kBOiCqiEpRo=
 gotest.tools/gotestsum v1.13.0/go.mod h1:7f0NS5hFb0dWr4NtcsAsF0y1kzjEFfAil0HiBQJE03Q=
 gotest.tools/v3 v3.5.2 h1:7koQfIKdy+I8UTetycgUqXWSDwpgv193Ka+qRsmBY8Q=