feat: pipe mode (stdin targets, naked-host, -silent plain output)

sif can now slot into unix pipelines. stdin is drained for targets when
it's a pipe (keyed off stdin's mode, not stdout), alongside -u/-f. naked
hosts are accepted and default to https://; explicit http(s) is kept,
other schemes rejected. -silent routes all banner/spinner/log chrome to
stderr and prints one normalized finding per line to stdout via
finding.Flatten, so `subfinder | sif -silent | notify` works.

README.md

@@ -216,6 +216,7 @@ write the run's findings out to a file for ci/cd or triage:
 |------|-------------|
 | `-sarif` | write a sarif 2.1.0 report to this file |
 | `-markdown`, `-md` | write a markdown report to this file |
+| `-silent` | plain output: chrome to stderr, one finding per line to stdout (for pipelines) |
 
 ```bash
 # scan and emit both a sarif and markdown report
@@ -224,6 +225,21 @@ write the run's findings out to a file for ci/cd or triage:
 
 sarif output is ingestable by github code scanning; markdown is a readable per-target summary.
 
+### pipe mode
+
+sif reads targets from stdin and accepts naked hosts, so it drops into a unix pipeline. `-silent` routes all banner/spinner/log chrome to stderr and prints one normalized finding per line (`[severity] target module title`) to stdout:
+
+```bash
+# subfinder feeds hosts, sif probes them, notify ships the findings
+subfinder -d example.com | sif -silent -probe | notify
+```
+
+| flag | description |
+|------|-------------|
+| stdin | a piped target stream (one host/url per line) is read alongside `-u`/`-f` |
+
+scheme-less hosts default to `https://`; an explicit `http://`/`https://` is kept; any other scheme (`ftp://`, ...) is rejected.
+
 ### yaml modules
 
 list available modules:

cmd/sif/main.go

@@ -52,7 +52,9 @@ func main() {
 		log.Fatal(err)
 	}
 
-	if !settings.ApiMode {
+	// patchnotes print to stdout; skip them in api/silent mode so the only thing
+	// on stdout is the machine-readable result stream.
+	if !settings.ApiMode && !settings.Silent {
 		patchnotes.ShowOnce(version)
 	}
 

docs/usage.md

@@ -21,6 +21,23 @@ read targets from a file (one url per line):
 ./sif -f targets.txt
 ```
 
+### stdin (pipe mode)
+
+when stdin is a pipe, sif reads one target per line from it, alongside any `-u`/`-f` targets. this lets sif slot into a unix pipeline:
+
+```bash
+subfinder -d example.com | sif -silent -probe | notify
+```
+
+### naked hosts
+
+targets without a scheme default to `https://`; an explicit `http://`/`https://` is kept as given. any other scheme (`ftp://`, `file://`, ...) is rejected:
+
+```bash
+./sif -u example.com          # scanned as https://example.com
+echo example.com | sif -probe # same, over stdin
+```
+
 ## scan options
 
 ### directory fuzzing
@@ -391,6 +408,14 @@ write a readable markdown report grouped by target, then by module:
 ./sif -u https://example.com -headers -cors -md report.md
 ```
 
+### -silent
+
+plain output for pipelines: all banner/spinner/log chrome goes to stderr and stdout carries one normalized finding per line, formatted `[severity] target module title`. implies non-interactive (no spinners), so a downstream consumer sees nothing but findings:
+
+```bash
+subfinder -d example.com | sif -silent -probe -sh | notify
+```
+
 ## api options
 
 ### -api

internal/config/config.go

@@ -65,6 +65,7 @@ type Settings struct {
 	Probe             bool
 	SARIF             string // path to write a sarif 2.1.0 report to ("" = off)
 	Markdown          string // path to write a markdown report to ("" = off)
+	Silent            bool   // route chrome to stderr, print one finding per line to stdout
 	Modules           string // Comma-separated list of module IDs to run
 	ModuleTags        string // Run modules matching these tags
 	AllModules        bool   // Run all loaded modules
@@ -166,6 +167,7 @@ func Parse() *Settings {
 	flagSet.CreateGroup("output", "Output",
 		flagSet.StringVar(&settings.SARIF, "sarif", "", "Write a SARIF 2.1.0 report to this file"),
 		flagSet.StringVarP(&settings.Markdown, "markdown", "md", "", "Write a markdown report to this file"),
+		flagSet.BoolVar(&settings.Silent, "silent", false, "Plain output: chrome to stderr, one finding per line to stdout (for pipelines)"),
 	)
 
 	flagSet.CreateGroup("api", "API",

internal/finding/finding.go

@@ -41,6 +41,15 @@ type Finding struct {
 	Raw      string   // short evidence string, not the full body
 }
 
+// Line renders a finding as one stable, terse, machine-friendly line for the
+// -silent plain sink: "[severity] target module title". no styling, no color -
+// a downstream pipe (notify, grep, awk) keys off the bracketed severity and the
+// fixed field order, so the shape stays frozen. pointer receiver: Finding is
+// wide enough that copying it per line is wasteful.
+func (f *Finding) Line() string {
+	return fmt.Sprintf("[%s] %s %s %s", f.Severity, f.Target, f.Module, f.Title)
+}
+
 // static per-module severities for results that carry no severity field of
 // their own. these are the editorial baseline; a scanner that emits its own
 // severity (cors, xss, nuclei, ...) overrides this on a per-item basis.

internal/finding/line_test.go

@@ -0,0 +1,48 @@
+/*
+·━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━·
+:                                                                               :
+:   █▀ █ █▀▀   ·   Blazing-fast pentesting suite                                :
+:   ▄█ █ █▀    ·   BSD 3-Clause License                                         :
+:                                                                               :
+:   (c) 2022-2026 vmfunc, xyzeva,                                               :
+:                 lunchcat alumni & contributors                                :
+:                                                                               :
+·━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━·
+*/
+
+package finding
+
+import "testing"
+
+// Line is the -silent wire format; its shape is frozen, so pin it.
+func TestFindingLine(t *testing.T) {
+	tests := []struct {
+		name string
+		f    Finding
+		want string
+	}{
+		{
+			name: "high severity",
+			f:    Finding{Target: "https://x.com", Module: "sql", Severity: SeverityHigh, Title: "admin panel"},
+			want: "[high] https://x.com sql admin panel",
+		},
+		{
+			name: "info recon",
+			f:    Finding{Target: "https://y.com", Module: "headers", Severity: SeverityInfo, Title: "Server"},
+			want: "[info] https://y.com headers Server",
+		},
+		{
+			name: "unknown severity",
+			f:    Finding{Target: "z.com", Module: "mystery", Severity: SeverityUnknown, Title: "?"},
+			want: "[unknown] z.com mystery ?",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := tt.f.Line(); got != tt.want {
+				t.Errorf("Line() = %q, want %q", got, tt.want)
+			}
+		})
+	}
+}

internal/output/output.go

@@ -14,6 +14,7 @@ package output
 
 import (
 	"fmt"
+	"io"
 	"os"
 	"strings"
 
@@ -126,13 +127,47 @@ func SetAPIMode(enabled bool) {
 	apiMode = enabled
 }
 
+// sink is where all banner/spinner/log chrome is written. it defaults to stdout
+// so normal runs are unchanged; -silent repoints it at stderr so stdout carries
+// nothing but the machine-readable findings a downstream pipe consumes.
+var sink io.Writer = os.Stdout
+
+// silent is the plain-sink mode: chrome goes to stderr and interactive widgets
+// (spinners, live progress) are suppressed so a piped consumer never sees them.
+var silent bool
+
+// SetSilent routes all chrome to stderr and marks the run non-interactive.
+// findings are printed to stdout by the caller via Finding/PrintFinding; the
+// output package itself never touches stdout once silent is on.
+func SetSilent(enabled bool) {
+	silent = enabled
+	if enabled {
+		sink = os.Stderr
+		return
+	}
+	sink = os.Stdout
+}
+
+// Silent reports whether plain-sink mode is active. callers gate interactive
+// behaviour (spinners, prompts) on this.
+func Silent() bool {
+	return silent
+}
+
+// Writer is the current chrome sink (stdout normally, stderr under -silent).
+// callers that render their own chrome (the startup banner) write here so it
+// follows the same routing as everything else.
+func Writer() io.Writer {
+	return sink
+}
+
 // Info prints an informational message with [*] prefix
 func Info(format string, args ...interface{}) {
 	if apiMode {
 		return
 	}
 	msg := fmt.Sprintf(format, args...)
-	fmt.Printf("%s %s\n", prefixInfo.Render("[*]"), msg)
+	fmt.Fprintf(sink, "%s %s\n", prefixInfo.Render("[*]"), msg)
 }
 
 // Success prints a success message with [+] prefix
@@ -141,7 +176,7 @@ func Success(format string, args ...interface{}) {
 		return
 	}
 	msg := fmt.Sprintf(format, args...)
-	fmt.Printf("%s %s\n", prefixSuccess.Render("[+]"), msg)
+	fmt.Fprintf(sink, "%s %s\n", prefixSuccess.Render("[+]"), msg)
 }
 
 // Warn prints a warning message with [!] prefix
@@ -150,7 +185,7 @@ func Warn(format string, args ...interface{}) {
 		return
 	}
 	msg := fmt.Sprintf(format, args...)
-	fmt.Printf("%s %s\n", prefixWarning.Render("[!]"), msg)
+	fmt.Fprintf(sink, "%s %s\n", prefixWarning.Render("[!]"), msg)
 }
 
 // Error prints an error message with [-] prefix
@@ -159,7 +194,7 @@ func Error(format string, args ...interface{}) {
 		return
 	}
 	msg := fmt.Sprintf(format, args...)
-	fmt.Printf("%s %s\n", prefixError.Render("[-]"), msg)
+	fmt.Fprintf(sink, "%s %s\n", prefixError.Render("[-]"), msg)
 }
 
 // ScanStart prints a styled scan start message
@@ -167,7 +202,7 @@ func ScanStart(scanName string) {
 	if apiMode {
 		return
 	}
-	fmt.Printf("%s starting %s\n", prefixInfo.Render("[*]"), scanName)
+	fmt.Fprintf(sink, "%s starting %s\n", prefixInfo.Render("[*]"), scanName)
 }
 
 // ScanComplete prints a styled scan completion message
@@ -175,7 +210,7 @@ func ScanComplete(scanName string, resultCount int, resultType string) {
 	if apiMode {
 		return
 	}
-	fmt.Printf("%s %s complete (%d %s)\n", prefixInfo.Render("[*]"), scanName, resultCount, resultType)
+	fmt.Fprintf(sink, "%s %s complete (%d %s)\n", prefixInfo.Render("[*]"), scanName, resultCount, resultType)
 }
 
 // Module creates a prefixed logger for a specific module/tool
@@ -202,7 +237,7 @@ func (m *ModuleLogger) Info(format string, args ...interface{}) {
 		return
 	}
 	msg := fmt.Sprintf(format, args...)
-	fmt.Printf("%s %s\n", m.prefix(), msg)
+	fmt.Fprintf(sink, "%s %s\n", m.prefix(), msg)
 }
 
 // Success prints a success message with module prefix
@@ -211,7 +246,7 @@ func (m *ModuleLogger) Success(format string, args ...interface{}) {
 		return
 	}
 	msg := fmt.Sprintf(format, args...)
-	fmt.Printf("%s %s %s\n", m.prefix(), prefixSuccess.Render("✓"), msg)
+	fmt.Fprintf(sink, "%s %s %s\n", m.prefix(), prefixSuccess.Render("✓"), msg)
 }
 
 // Warn prints a warning message with module prefix
@@ -220,7 +255,7 @@ func (m *ModuleLogger) Warn(format string, args ...interface{}) {
 		return
 	}
 	msg := fmt.Sprintf(format, args...)
-	fmt.Printf("%s %s %s\n", m.prefix(), prefixWarning.Render("!"), msg)
+	fmt.Fprintf(sink, "%s %s %s\n", m.prefix(), prefixWarning.Render("!"), msg)
 }
 
 // Error prints an error message with module prefix
@@ -229,7 +264,7 @@ func (m *ModuleLogger) Error(format string, args ...interface{}) {
 		return
 	}
 	msg := fmt.Sprintf(format, args...)
-	fmt.Printf("%s %s %s\n", m.prefix(), prefixError.Render("✗"), msg)
+	fmt.Fprintf(sink, "%s %s %s\n", m.prefix(), prefixError.Render("✗"), msg)
 }
 
 // Start prints a scan start message with module prefix (adds newline before for separation)
@@ -237,7 +272,7 @@ func (m *ModuleLogger) Start() {
 	if apiMode {
 		return
 	}
-	fmt.Printf("\n%s starting scan\n", m.prefix())
+	fmt.Fprintf(sink, "\n%s starting scan\n", m.prefix())
 }
 
 // Complete prints a scan complete message with module prefix
@@ -245,15 +280,16 @@ func (m *ModuleLogger) Complete(resultCount int, resultType string) {
 	if apiMode {
 		return
 	}
-	fmt.Printf("%s complete (%d %s)\n", m.prefix(), resultCount, resultType)
+	fmt.Fprintf(sink, "%s complete (%d %s)\n", m.prefix(), resultCount, resultType)
 }
 
-// ClearLine clears the current line (for progress bar updates)
+// ClearLine clears the current line (for progress bar updates). silent mode is
+// non-interactive, so there's no live line to clear and stdout stays untouched.
 func ClearLine() {
-	if !IsTTY {
+	if !IsTTY || silent {
 		return
 	}
-	fmt.Print("\033[2K\r")
+	fmt.Fprint(sink, "\033[2K\r")
 }
 
 // Summary styles
@@ -274,22 +310,22 @@ func PrintSummary(scans []string, logFiles []string) {
 		return
 	}
 
-	fmt.Println()
-	fmt.Println(summaryLine.Render("────────────────────────────────────────────────────────────"))
-	fmt.Println()
-	fmt.Printf("  %s\n", summaryHeader.Render("SCAN COMPLETE"))
-	fmt.Println()
+	fmt.Fprintln(sink)
+	fmt.Fprintln(sink, summaryLine.Render("────────────────────────────────────────────────────────────"))
+	fmt.Fprintln(sink)
+	fmt.Fprintf(sink, "  %s\n", summaryHeader.Render("SCAN COMPLETE"))
+	fmt.Fprintln(sink)
 
 	// Print scans
 	scanList := strings.Join(scans, ", ")
-	fmt.Printf("  %s %s\n", Muted.Render("Scans:"), scanList)
+	fmt.Fprintf(sink, "  %s %s\n", Muted.Render("Scans:"), scanList)
 
 	// Print log files if any
 	if len(logFiles) > 0 {
-		fmt.Printf("  %s %s\n", Muted.Render("Output:"), strings.Join(logFiles, ", "))
+		fmt.Fprintf(sink, "  %s %s\n", Muted.Render("Output:"), strings.Join(logFiles, ", "))
 	}
 
-	fmt.Println()
-	fmt.Println(summaryLine.Render("────────────────────────────────────────────────────────────"))
-	fmt.Println()
+	fmt.Fprintln(sink)
+	fmt.Fprintln(sink, summaryLine.Render("────────────────────────────────────────────────────────────"))
+	fmt.Fprintln(sink)
 }

internal/output/progress.go

@@ -98,7 +98,7 @@ func (p *Progress) Done() {
 }
 
 func (p *Progress) render() {
-	if apiMode {
+	if apiMode || silent {
 		return
 	}
 
@@ -135,7 +135,7 @@ func (p *Progress) render() {
 		p.mu.Unlock()
 
 		if advanced {
-			fmt.Printf("    [%d%%] %d/%d\n", percent, current, total)
+			fmt.Fprintf(sink, "    [%d%%] %d/%d\n", percent, current, total)
 		}
 		return
 	}
@@ -190,5 +190,5 @@ func (p *Progress) render() {
 	)
 
 	ClearLine()
-	fmt.Print(line)
+	fmt.Fprint(sink, line)
 }

internal/output/silent_test.go

@@ -0,0 +1,113 @@
+/*
+·━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━·
+:                                                                               :
+:   █▀ █ █▀▀   ·   Blazing-fast pentesting suite                                :
+:   ▄█ █ █▀    ·   BSD 3-Clause License                                         :
+:                                                                               :
+:   (c) 2022-2026 vmfunc, xyzeva,                                               :
+:                 lunchcat alumni & contributors                                :
+:                                                                               :
+·━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━·
+*/
+
+package output
+
+import (
+	"os"
+	"strings"
+	"testing"
+)
+
+// in silent mode chrome must land on stderr and leave stdout untouched, so a
+// piped consumer downstream never sees a banner or log line.
+func TestSetSilentRoutesChromeToStderr(t *testing.T) {
+	defer SetSilent(false)
+
+	outStr, errStr := captureStdoutStderr(t, func() {
+		// SetSilent reads os.Stderr at call time, so swap then set.
+		SetSilent(true)
+		Info("scanning %s", "example.com")
+		Success("done")
+	})
+
+	if outStr != "" {
+		t.Errorf("silent mode wrote chrome to stdout: %q", outStr)
+	}
+	if !strings.Contains(errStr, "scanning example.com") {
+		t.Errorf("silent chrome missing from stderr: %q", errStr)
+	}
+}
+
+// the default (non-silent) sink is stdout; flipping silent off must restore it.
+func TestSetSilentOffRoutesChromeToStdout(t *testing.T) {
+	outStr, errStr := captureStdoutStderr(t, func() {
+		SetSilent(false)
+		Info("hello")
+	})
+
+	if !strings.Contains(outStr, "hello") {
+		t.Errorf("non-silent chrome missing from stdout: %q", outStr)
+	}
+	if strings.Contains(errStr, "hello") {
+		t.Errorf("non-silent chrome leaked to stderr: %q", errStr)
+	}
+}
+
+// Silent() reflects the toggle so callers can gate interactive widgets.
+func TestSilentToggle(t *testing.T) {
+	defer SetSilent(false)
+	SetSilent(true)
+	if !Silent() {
+		t.Error("Silent() = false after SetSilent(true)")
+	}
+	SetSilent(false)
+	if Silent() {
+		t.Error("Silent() = true after SetSilent(false)")
+	}
+}
+
+// captureStdoutStderr swaps both real streams for pipes, runs fn, and returns
+// what landed on each. SetSilent reads os.Stdout/os.Stderr at call time, so the
+// swap has to happen before fn flips the sink - fn does that itself.
+func captureStdoutStderr(t *testing.T, fn func()) (string, string) {
+	t.Helper()
+
+	outR, outW, err := os.Pipe()
+	if err != nil {
+		t.Fatalf("pipe stdout: %v", err)
+	}
+	errR, errW, err := os.Pipe()
+	if err != nil {
+		t.Fatalf("pipe stderr: %v", err)
+	}
+
+	savedOut, savedErr := os.Stdout, os.Stderr
+	os.Stdout, os.Stderr = outW, errW
+
+	outCh := drain(outR)
+	errCh := drain(errR)
+
+	fn()
+
+	os.Stdout, os.Stderr = savedOut, savedErr
+	outW.Close()
+	errW.Close()
+	return <-outCh, <-errCh
+}
+
+func drain(r *os.File) <-chan string {
+	ch := make(chan string, 1)
+	go func() {
+		buf := make([]byte, 0, 4096)
+		tmp := make([]byte, 1024)
+		for {
+			n, rerr := r.Read(tmp)
+			buf = append(buf, tmp[:n]...)
+			if rerr != nil {
+				break
+			}
+		}
+		ch <- string(buf)
+	}()
+	return ch
+}

internal/output/spinner.go

@@ -14,7 +14,6 @@ package output
 
 import (
 	"fmt"
-	"os"
 	"sync"
 	"time"
 )
@@ -42,7 +41,7 @@ func NewSpinner(message string) *Spinner {
 
 // Start begins the spinner animation
 func (s *Spinner) Start() {
-	if apiMode {
+	if apiMode || silent {
 		return
 	}
 
@@ -57,7 +56,7 @@ func (s *Spinner) Start() {
 
 	// In non-TTY mode, just print the message once
 	if !IsTTY {
-		fmt.Printf("    %s...\n", s.message)
+		fmt.Fprintf(sink, "    %s...\n", s.message)
 		return
 	}
 
@@ -66,7 +65,7 @@ func (s *Spinner) Start() {
 
 // Stop halts the spinner and clears the line
 func (s *Spinner) Stop() {
-	if apiMode {
+	if apiMode || silent {
 		return
 	}
 
@@ -112,8 +111,8 @@ func (s *Spinner) animate() {
 			spinnerChar := prefixInfo.Render(spinnerFrames[frame])
 			line := fmt.Sprintf("\r    %s %s", spinnerChar, msg)
 
-			fmt.Fprint(os.Stdout, "\033[2K") // Clear line
-			fmt.Fprint(os.Stdout, line)
+			fmt.Fprint(sink, "\033[2K") // Clear line
+			fmt.Fprint(sink, line)
 
 			frame = (frame + 1) % len(spinnerFrames)
 		}

man/sif.1

@@ -1,5 +1,5 @@
 .\" man page for sif - the blazing-fast pentesting suite
-.TH sif 1 "2026-06-08" "sif" "sif manual"
+.TH sif 1 "2026-06-10" "sif" "sif manual"
 .SH NAME
 sif \- blazing-fast pentesting suite
 .SH SYNOPSIS
@@ -15,17 +15,25 @@ sif \- blazing-fast pentesting suite
 .RI [ scans ]
 .RI [ options ]
 .br
+.I "targets"
+|
+.B sif
+.RI [ scans ]
+.RI [ options ]
+.br
 .B sif
 .RB { patchnote | version }
 .SH DESCRIPTION
 .B sif
 is a modular recon and exploitation suite. it runs multiple scan types
 concurrently against one or more targets, and can be extended with yaml
-modules. targets must include a
+modules. a scheme\-less target defaults to
+.B https://
+\&; an explicit
 .B http://
 or
 .B https://
-scheme.
+is kept; any other scheme is rejected.
 .SH TARGETS
 .TP
 .BR \-u ", " \-\-urls " \fIlist\fR"
@@ -33,6 +41,13 @@ comma\-separated list of urls to scan.
 .TP
 .BR \-f ", " \-\-file " \fIpath\fR"
 file with one url per line.
+.TP
+.B stdin
+when stdin is a pipe, one target per line is read from it, alongside any
+.B \-u
+/
+.B \-f
+targets. lets sif slot into a unix pipeline (e.g. \fBsubfinder | sif \-silent | notify\fR).
 .SH SCANS
 .TP
 .BR \-dirlist " \fIsize\fR"
@@ -171,6 +186,11 @@ write a sarif 2.1.0 report of the run to \fIfile\fR.
 .BR \-md ", " \-\-markdown " \fIfile\fR"
 write a markdown report of the run to \fIfile\fR.
 .TP
+.B \-silent
+plain output for pipelines: route all chrome to stderr and print one
+normalized finding per line to stdout as \fB[severity] target module title\fR.
+implies non\-interactive (no spinners).
+.TP
 .B \-api
 emit json results and suppress the interactive output.
 .SH MODULES

sif.go

@@ -20,6 +20,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"io"
 	"os"
 	"strings"
 
@@ -85,13 +86,19 @@ func NewModuleResult[T ScanResult](data T) ModuleResult {
 func New(settings *config.Settings) (*App, error) {
 	app := &App{settings: settings}
 
+	// -silent reroutes all chrome to stderr (and suppresses spinners) before the
+	// banner prints, so stdout carries nothing but findings even on the banner.
+	if settings.Silent {
+		output.SetSilent(true)
+	}
+
 	if !settings.ApiMode {
-		fmt.Println(output.Box.Render("   █▀ █ █▀▀\n  ▄█ █ █▀ "))
+		fmt.Fprintln(output.Writer(), output.Box.Render("   █▀ █ █▀▀\n  ▄█ █ █▀ "))
 		tagline := "blazing-fast pentesting suite"
 		if Version != "dev" {
 			tagline += " · v" + Version
 		}
-		fmt.Println(output.Subheading.Render("\n" + tagline + "\n\nbsd 3-clause · (c) 2022-2026 vmfunc, xyzeva & contributors\n"))
+		fmt.Fprintln(output.Writer(), output.Subheading.Render("\n"+tagline+"\n\nbsd 3-clause · (c) 2022-2026 vmfunc, xyzeva & contributors\n"))
 	} else {
 		output.SetAPIMode(true)
 	}
@@ -101,10 +108,11 @@ func New(settings *config.Settings) (*App, error) {
 		return app, nil
 	}
 
-	switch {
-	case len(settings.URLs) > 0:
-		app.targets = settings.URLs
-	case settings.File != "":
+	// -u and -f are explicit; stdin is additive so `subfinder | sif -u extra`
+	// still works. order: flags first, then piped lines appended.
+	app.targets = append(app.targets, settings.URLs...)
+
+	if settings.File != "" {
 		if _, err := os.Stat(settings.File); err != nil {
 			return nil, err
 		}
@@ -120,29 +128,105 @@ func New(settings *config.Settings) (*App, error) {
 		for scanner.Scan() {
 			app.targets = append(app.targets, scanner.Text())
 		}
-	default:
-		return nil, fmt.Errorf("target(s) must be supplied with -u or -f\n\nSee 'sif -h' for more information")
 	}
 
-	// Validate all URLs early
-	for _, url := range app.targets {
-		if err := validateURL(url); err != nil {
+	// when stdin is a pipe (not a terminal), drain it for targets so sif slots
+	// into a unix pipeline: `subfinder -d x | sif -silent | notify`. keyed off
+	// stdin's mode, never stdout - a redirected stdout (>file) is not a pipe in.
+	piped, err := stdinPipedFn()
+	if err != nil {
+		return nil, err
+	}
+	if piped {
+		stdinTargets, err := readTargets(stdinReader)
+		if err != nil {
+			return nil, fmt.Errorf("reading targets from stdin: %w", err)
+		}
+		app.targets = append(app.targets, stdinTargets...)
+	}
+
+	if len(app.targets) == 0 {
+		return nil, fmt.Errorf("target(s) must be supplied with -u, -f, or stdin\n\nSee 'sif -h' for more information")
+	}
+
+	// normalize every target in place: a naked host gains a default scheme, an
+	// explicit scheme is kept, genuinely invalid input is rejected early.
+	for i := 0; i < len(app.targets); i++ {
+		normalized, err := normalizeTarget(app.targets[i])
+		if err != nil {
 			return nil, err
 		}
+		app.targets[i] = normalized
 	}
 
 	return app, nil
 }
 
-// validateURL checks that a URL has a valid HTTP/HTTPS protocol.
-func validateURL(url string) error {
-	if url == "" {
-		return fmt.Errorf("empty URL provided")
+// defaultScheme is prepended to scheme-less targets. https is the safer default
+// for recon: it's what modern hosts serve and avoids a cleartext first hop.
+const defaultScheme = "https://"
+
+// stdin ingestion is wired through two seams so it's hermetically testable: the
+// pipe check and the reader can be swapped in tests without touching real fds.
+var (
+	stdinPipedFn           = stdinPiped
+	stdinReader  io.Reader = os.Stdin
+)
+
+// stdinPiped reports whether stdin is a pipe/redirect rather than a terminal.
+// a char device (the tty) means interactive with no piped input; anything else
+// (pipe, file redirect) is treated as a target stream.
+func stdinPiped() (bool, error) {
+	info, err := os.Stdin.Stat()
+	if err != nil {
+		return false, fmt.Errorf("stat stdin: %w", err)
 	}
-	if !strings.HasPrefix(url, "http://") && !strings.HasPrefix(url, "https://") {
-		return fmt.Errorf("URL %s must include http:// or https:// protocol", url)
+	return info.Mode()&os.ModeCharDevice == 0, nil
+}
+
+// readTargets scans one target per line from r, dropping blank lines and
+// trimming surrounding whitespace. shared by the stdin path; the file path keeps
+// its own scanner since it preserves lines verbatim for back-compat.
+func readTargets(r io.Reader) ([]string, error) {
+	var out []string
+	scanner := bufio.NewScanner(r)
+	scanner.Split(bufio.ScanLines)
+	for scanner.Scan() {
+		line := strings.TrimSpace(scanner.Text())
+		if line == "" {
+			continue
+		}
+		out = append(out, line)
 	}
-	return nil
+	if err := scanner.Err(); err != nil {
+		return nil, fmt.Errorf("scanning targets: %w", err)
+	}
+	return out, nil
+}
+
+// normalizeTarget canonicalizes a single target. a scheme-less host gets the
+// default scheme; an http:// or https:// target is kept as-is. an empty string
+// or a non-http(s) scheme (ftp://, file://, ...) is rejected so junk can't slip
+// into the scan loop.
+func normalizeTarget(target string) (string, error) {
+	target = strings.TrimSpace(target)
+	if target == "" {
+		return "", fmt.Errorf("empty target provided")
+	}
+	if strings.HasPrefix(target, "http://") || strings.HasPrefix(target, "https://") {
+		return target, nil
+	}
+	// reject anything that carries some other scheme; "://" present but not
+	// http(s) is a deliberate non-web target, not a naked host.
+	if strings.Contains(target, "://") {
+		return "", fmt.Errorf("target %s must use http:// or https:// scheme", target)
+	}
+	// a bare "host:port" or path-only token would also be ambiguous; require at
+	// least a host-looking first segment (no spaces) before defaulting a scheme.
+	if strings.ContainsAny(target, " \t") {
+		return "", fmt.Errorf("invalid target %q", target)
+	}
+	return defaultScheme + target, nil
 }
 
 // Run runs the pentesting suite, with the targets specified, according to the
@@ -562,6 +646,13 @@ func (app *App) Run() error {
 	// count now so the path is live and observable without changing output.
 	log.Debugf("normalized %d findings across %d targets", len(allFindings), len(app.targets))
 
+	// -silent: stdout is the findings stream, one terse line each. all chrome
+	// already went to stderr via the rerouted sink, so this is the only thing a
+	// downstream pipe sees.
+	if app.settings.Silent {
+		printFindings(allFindings)
+	}
+
 	if wantReport {
 		if err := app.writeReports(reportResults); err != nil {
 			return err
@@ -575,6 +666,18 @@ func (app *App) Run() error {
 	return nil
 }
 
+// printFindings writes one normalized finding per line to stdout for the
+// -silent plain sink. a single Builder over the run avoids interleaving with
+// any stray stderr chrome and keeps the write to one syscall.
+func printFindings(findings []finding.Finding) {
+	var b strings.Builder
+	for i := 0; i < len(findings); i++ {
+		b.WriteString(findings[i].Line())
+		b.WriteByte('\n')
+	}
+	fmt.Print(b.String())
+}
+
 // collectFindings normalizes one target's module results through finding.Flatten
 // - the single normalization path that notify and diff (later bundles) build on.
 // every scan result struct collapses to flat, severity-ranked findings here so a

sif_test.go

@@ -13,11 +13,24 @@
 package sif
 
 import (
+	"io"
+	"os"
+	"strings"
 	"testing"
 
 	"github.com/dropalldatabases/sif/internal/config"
+	"github.com/dropalldatabases/sif/internal/finding"
 )
 
+// TestMain neutralizes the stdin seam for the whole package so tests that build
+// an App via New() never block on the test runner's real stdin (a pipe under
+// `go test`). tests that exercise ingestion set the seams explicitly.
+func TestMain(m *testing.M) {
+	stdinPipedFn = func() (bool, error) { return false, nil }
+	stdinReader = strings.NewReader("")
+	os.Exit(m.Run())
+}
+
 // mockResult is a test implementation of ScanResult
 type mockResult struct {
 	name string
@@ -117,20 +130,16 @@ func TestNew_URLValidation(t *testing.T) {
 			wantErr: false,
 		},
 		{
+			// naked host is now accepted and normalized, not rejected
 			name:    "missing protocol",
 			url:     "example.com",
-			wantErr: true,
+			wantErr: false,
 		},
 		{
 			name:    "invalid protocol",
 			url:     "ftp://example.com",
 			wantErr: true,
 		},
-		{
-			name:    "empty url",
-			url:     "",
-			wantErr: true,
-		},
 	}
 
 	for _, tt := range tests {
@@ -148,6 +157,194 @@ func TestNew_URLValidation(t *testing.T) {
 	}
 }
 
+func TestNormalizeTarget(t *testing.T) {
+	tests := []struct {
+		name    string
+		in      string
+		want    string
+		wantErr bool
+	}{
+		{name: "naked host defaults https", in: "example.com", want: "https://example.com"},
+		{name: "naked host with port", in: "example.com:8443", want: "https://example.com:8443"},
+		{name: "naked host with path", in: "example.com/admin", want: "https://example.com/admin"},
+		{name: "https kept", in: "https://example.com", want: "https://example.com"},
+		{name: "http kept", in: "http://example.com", want: "http://example.com"},
+		{name: "surrounding whitespace trimmed", in: "  example.com\t", want: "https://example.com"},
+		{name: "empty rejected", in: "", wantErr: true},
+		{name: "blank rejected", in: "   ", wantErr: true},
+		{name: "ftp scheme rejected", in: "ftp://example.com", wantErr: true},
+		{name: "file scheme rejected", in: "file:///etc/passwd", wantErr: true},
+		{name: "embedded space rejected", in: "foo bar", wantErr: true},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := normalizeTarget(tt.in)
+			if (err != nil) != tt.wantErr {
+				t.Fatalf("normalizeTarget(%q) err = %v, wantErr %v", tt.in, err, tt.wantErr)
+			}
+			if err != nil {
+				return
+			}
+			if got != tt.want {
+				t.Errorf("normalizeTarget(%q) = %q, want %q", tt.in, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestNew_StdinIngestion(t *testing.T) {
+	// feed a pipe of targets and assert they're parsed and normalized alongside
+	// the explicit -u target. the seams stand in for a real stdin pipe.
+	origPiped, origReader := stdinPipedFn, stdinReader
+	t.Cleanup(func() { stdinPipedFn, stdinReader = origPiped, origReader })
+
+	stdinPipedFn = func() (bool, error) { return true, nil }
+	stdinReader = strings.NewReader("sub1.example.com\nhttps://sub2.example.com\n\n  sub3.example.com  \n")
+
+	settings := &config.Settings{
+		URLs:    []string{"https://flag.example.com"},
+		ApiMode: true,
+	}
+
+	app, err := New(settings)
+	if err != nil {
+		t.Fatalf("New() unexpected error: %v", err)
+	}
+
+	want := []string{
+		"https://flag.example.com",
+		"https://sub1.example.com",
+		"https://sub2.example.com",
+		"https://sub3.example.com",
+	}
+	if len(app.targets) != len(want) {
+		t.Fatalf("targets = %v (%d), want %d", app.targets, len(app.targets), len(want))
+	}
+	for i := range want {
+		if app.targets[i] != want[i] {
+			t.Errorf("target[%d] = %q, want %q", i, app.targets[i], want[i])
+		}
+	}
+}
+
+func TestNew_StdinOnly(t *testing.T) {
+	// no -u/-f: a piped stream alone must satisfy the target requirement.
+	origPiped, origReader := stdinPipedFn, stdinReader
+	t.Cleanup(func() { stdinPipedFn, stdinReader = origPiped, origReader })
+
+	stdinPipedFn = func() (bool, error) { return true, nil }
+	stdinReader = strings.NewReader("only.example.com\n")
+
+	app, err := New(&config.Settings{ApiMode: true})
+	if err != nil {
+		t.Fatalf("New() unexpected error: %v", err)
+	}
+	if len(app.targets) != 1 || app.targets[0] != "https://only.example.com" {
+		t.Errorf("targets = %v, want [https://only.example.com]", app.targets)
+	}
+}
+
+func TestNew_NoTargets_StdinEmpty(t *testing.T) {
+	// an empty pipe with no flags is still "no targets" and must error.
+	origPiped, origReader := stdinPipedFn, stdinReader
+	t.Cleanup(func() { stdinPipedFn, stdinReader = origPiped, origReader })
+
+	stdinPipedFn = func() (bool, error) { return true, nil }
+	stdinReader = strings.NewReader("\n  \n")
+
+	if _, err := New(&config.Settings{ApiMode: true}); err == nil {
+		t.Error("New() should error when stdin yields no targets and no flags set")
+	}
+}
+
+func TestReadTargets(t *testing.T) {
+	got, err := readTargets(strings.NewReader("a.com\n\n  b.com \nc.com\n"))
+	if err != nil {
+		t.Fatalf("readTargets() error: %v", err)
+	}
+	want := []string{"a.com", "b.com", "c.com"}
+	if len(got) != len(want) {
+		t.Fatalf("readTargets() = %v, want %v", got, want)
+	}
+	for i := range want {
+		if got[i] != want[i] {
+			t.Errorf("readTargets()[%d] = %q, want %q", i, got[i], want[i])
+		}
+	}
+}
+
+// errReader fails on first read; used to assert stdin scan errors propagate.
+type errReader struct{}
+
+func (errReader) Read([]byte) (int, error) { return 0, io.ErrClosedPipe }
+
+func TestReadTargets_Error(t *testing.T) {
+	if _, err := readTargets(errReader{}); err == nil {
+		t.Error("readTargets() should propagate a reader error")
+	}
+}
+
+func TestPrintFindings(t *testing.T) {
+	findings := []finding.Finding{
+		{Target: "https://a.com", Module: "sql", Severity: finding.SeverityHigh, Title: "admin panel"},
+		{Target: "https://b.com", Module: "headers", Severity: finding.SeverityInfo, Title: "Server"},
+	}
+
+	out := captureStdout(t, func() { printFindings(findings) })
+
+	wantLines := []string{
+		"[high] https://a.com sql admin panel",
+		"[info] https://b.com headers Server",
+	}
+	got := strings.Split(strings.TrimRight(out, "\n"), "\n")
+	if len(got) != len(wantLines) {
+		t.Fatalf("printFindings wrote %d lines, want %d:\n%s", len(got), len(wantLines), out)
+	}
+	for i := range wantLines {
+		if got[i] != wantLines[i] {
+			t.Errorf("line %d = %q, want %q", i, got[i], wantLines[i])
+		}
+	}
+}
+
+func TestPrintFindings_Empty(t *testing.T) {
+	out := captureStdout(t, func() { printFindings(nil) })
+	if out != "" {
+		t.Errorf("printFindings(nil) wrote %q, want empty", out)
+	}
+}
+
+// captureStdout swaps os.Stdout for a pipe, runs fn, and returns what it wrote.
+func captureStdout(t *testing.T, fn func()) string {
+	t.Helper()
+	r, w, err := os.Pipe()
+	if err != nil {
+		t.Fatalf("pipe: %v", err)
+	}
+	saved := os.Stdout
+	os.Stdout = w
+
+	done := make(chan string, 1)
+	go func() {
+		buf := make([]byte, 0, 4096)
+		tmp := make([]byte, 1024)
+		for {
+			n, rerr := r.Read(tmp)
+			buf = append(buf, tmp[:n]...)
+			if rerr != nil {
+				break
+			}
+		}
+		done <- string(buf)
+	}()
+
+	fn()
+	os.Stdout = saved
+	w.Close()
+	return <-done
+}
+
 func TestModuleResult_JSON(t *testing.T) {
 	mr := ModuleResult{
 		Id:   "test",