Add batch check command and safety features to CLI

Features added:
- Extended check command to support batch checking: `check <IP> <host1> <host2>...`
- Added --quiet flag for check command (only return exit codes)
- Added --any flag for check command (match ANY instead of ALL hosts)
- Added --backup global flag to create backup before modifying hosts
- Added --safe global flag to detect concurrent modifications
- Added flushHostsfile() helper that implements backup and safety checks

Command updates:
- add, remove, clean now use flushHostsfile() for safe writes
- Backward compatible: single-arg check behavior preserved

Dependencies:
- Updated go.mod to use local hostsfile library with VVV improvements

Exit codes:
- 0: Success (host(s) found or operation completed)
- 1: Check failed (host not found)
- 2: Invalid arguments

This enables VVV vagrant plugin to:
- Check hosts without sudo (read-only operation)
- Only request sudo when hosts are actually missing

Author: tomjn

cmd/add.go

@@ -68,7 +68,7 @@ func add(c *cli.Context) error {
 	}
 
 	logrus.Debugln("flushing hosts file to disk")
-	if err := hf.Flush(); err != nil {
+	if err := flushHostsfile(c, hf); err != nil {
 		return cli.Exit(err.Error(), 2)
 	}
 

cmd/app.go

@@ -60,6 +60,15 @@ var (
 				Aliases: []string{"q"},
 				Usage:   "Turn on off all logging",
 			},
+			&cli.BoolFlag{
+				Name:    "backup",
+				Aliases: []string{"b"},
+				Usage:   "Create backup before modifying hosts file",
+			},
+			&cli.BoolFlag{
+				Name:  "safe",
+				Usage: "Check for concurrent modifications before writing",
+			},
 		},
 	}
 )
@@ -110,6 +119,28 @@ func loadHostsfile(c *cli.Context, readOnly bool) (*hostsfile.Hosts, error) {
 	return hf, nil
 }
 
+func flushHostsfile(c *cli.Context, hf *hostsfile.Hosts) error {
+	if c.Bool("safe") {
+		modified, err := hf.HasBeenModified()
+		if err != nil {
+			return err
+		}
+		if modified {
+			return fmt.Errorf("hosts file was modified by another process; reload and retry")
+		}
+	}
+
+	if c.Bool("backup") {
+		if err := hf.Backup(); err != nil {
+			logrus.Warnf("Failed to create backup: %v", err)
+		} else {
+			logrus.Debugf("Backup created at: %s", hf.BackupPath())
+		}
+	}
+
+	return hf.Flush()
+}
+
 func outputHostsfile(hf *hostsfile.Hosts, all bool) {
 	for _, line := range hf.Lines {
 		if !all {

cmd/check.go

@@ -12,34 +12,96 @@ func Check() *cli.Command {
 	return &cli.Command{
 		Name:      "check",
 		Aliases:   []string{"c"},
-		Usage:     "Check if ip or host exists",
+		Usage:     "Check if ip or host exists. With IP and hosts: check if all hosts are mapped to IP",
 		Action:    check,
-		ArgsUsage: "[IP|HOST]",
+		ArgsUsage: "[IP|HOST] or [IP] [HOST] ([HOST]...)",
+		Flags: []cli.Flag{
+			&cli.BoolFlag{
+				Name:    "quiet",
+				Aliases: []string{"q"},
+				Usage:   "Suppress output, only return exit code",
+			},
+			&cli.BoolFlag{
+				Name:  "any",
+				Usage: "With multiple hosts: succeed if ANY host matches (default: ALL must match)",
+			},
+		},
 	}
 }
+
 func check(c *cli.Context) error {
 	if c.Args().Len() < 1 {
 		logrus.Infof("No input, pass an ip address or hostname to check.")
 		return nil
 	}
 
-	hf, err := loadHostsfile(c, true)
+	hf, err := loadHostsfile(c, true) // readOnly=true, no sudo needed
 	if err != nil {
 		return err
 	}
-	input := c.Args().First()
 
-	if net.ParseIP(input) != nil {
-		if hf.HasIP(input) {
-			logrus.Infof("%s exists in hosts file\n", input)
+	args := c.Args().Slice()
+	firstArg := args[0]
+	quiet := c.Bool("quiet")
+
+	// Single argument: check if IP or hostname exists (backward compatible)
+	if c.Args().Len() == 1 {
+		if net.ParseIP(firstArg) != nil {
+			if hf.HasIP(firstArg) {
+				if !quiet {
+					logrus.Infof("%s exists in hosts file\n", firstArg)
+				}
+				return nil
+			}
+		}
+
+		if hf.HasHostname(firstArg) {
+			if !quiet {
+				logrus.Infof("%s exists in hosts file\n", firstArg)
+			}
+			return nil
+		}
+
+		return cli.Exit(fmt.Sprintf("%s does not match anything in the hosts file", firstArg), 1)
+	}
+
+	// Multiple arguments: first must be IP, rest are hostnames
+	if net.ParseIP(firstArg) == nil {
+		return cli.Exit(fmt.Sprintf("%s is not a valid IP address. When checking multiple hosts, first argument must be an IP.", firstArg), 2)
+	}
+
+	ip := firstArg
+	hosts := args[1:]
+
+	if c.Bool("any") {
+		// Check if ANY host is mapped to IP
+		if hf.HasAny(ip, hosts...) {
+			if !quiet {
+				logrus.Infof("At least one host is mapped to %s\n", ip)
+			}
 			return nil
 		}
+		return cli.Exit(fmt.Sprintf("None of the specified hosts are mapped to %s", ip), 1)
 	}
 
-	if hf.HasHostname(input) {
-		logrus.Infof("%s exists in hosts file\n", input)
+	// Default: Check if ALL hosts are mapped to IP
+	if hf.HasAll(ip, hosts...) {
+		if !quiet {
+			logrus.Infof("All specified hosts are mapped to %s\n", ip)
+		}
 		return nil
 	}
 
-	return cli.Exit(fmt.Sprintf("%s does not match anything in the hosts file", input), 1)
+	// Report which hosts are missing
+	if !quiet {
+		missing := []string{}
+		for _, host := range hosts {
+			if !hf.Has(ip, host) {
+				missing = append(missing, host)
+			}
+		}
+		return cli.Exit(fmt.Sprintf("Missing hosts for %s: %v", ip, missing), 1)
+	}
+
+	return cli.Exit("", 1)
 }

cmd/clean.go

@@ -87,7 +87,7 @@ func clean(c *cli.Context) error {
 		return debugFooter(c)
 	}
 
-	if err := h.Flush(); err != nil {
+	if err := flushHostsfile(c, h); err != nil {
 		return cli.Exit(err.Error(), 2)
 	}
 	return debugFooter(c)

cmd/remove.go

@@ -85,7 +85,7 @@ func remove(c *cli.Context) error {
 	}
 
 	logrus.Debugln("flushing hosts file to disk")
-	if err := hf.Flush(); err != nil {
+	if err := flushHostsfile(c, hf); err != nil {
 		return cli.Exit(err.Error(), 2)
 	}
 

go.mod

@@ -7,7 +7,7 @@ require (
 	github.com/magefile/mage v1.15.0
 	github.com/olekukonko/tablewriter v0.0.5
 	github.com/sirupsen/logrus v1.9.3
-	github.com/stretchr/testify v1.8.2
+	github.com/stretchr/testify v1.8.4
 	github.com/t-tomalak/logrus-easy-formatter v0.0.0-20190827215021-c074f06c5816
 	github.com/urfave/cli/v2 v2.26.0
 	github.com/uwu-tools/magex v0.10.0
@@ -26,3 +26,6 @@ require (
 	golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )
+
+// Use local hostsfile library with VVV improvements
+replace github.com/goodhosts/hostsfile => ../hostsfile

go.sum

@@ -11,8 +11,6 @@ github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/dimchansky/utfbom v1.1.1 h1:vV6w1AhK4VMnhBno/TPVCoK9U/LP0PkLCS9tbxHdi/U=
 github.com/dimchansky/utfbom v1.1.1/go.mod h1:SxdoEBH5qIqFocHMyGOXVAybYJdr71b1Q/j0mACtrfE=
-github.com/goodhosts/hostsfile v0.1.6 h1:aK6DxpNV6pZ1NbdvNE2vYBMTnvIJF5O2J/8ZOlp2eMY=
-github.com/goodhosts/hostsfile v0.1.6/go.mod h1:bkCocEIf3Ca0hcBustUZoWYhOgKUaIK+47m8fBjoBx8=
 github.com/icrowley/fake v0.0.0-20221112152111-d7b7e2276db2 h1:qU3v73XG4QAqCPHA4HOpfC1EfUvtLIDvQK4mNQ0LvgI=
 github.com/icrowley/fake v0.0.0-20221112152111-d7b7e2276db2/go.mod h1:dQ6TM/OGAe+cMws81eTe4Btv1dKxfPZ2CX+YaAFAPN4=
 github.com/konsorten/go-windows-terminal-sequences v1.0.1/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
@@ -31,14 +29,10 @@ github.com/sirupsen/logrus v1.9.3 h1:dueUQJ1C2q9oE3F7wvmSGAaVtTmUizReu6fjN8uqzbQ
 github.com/sirupsen/logrus v1.9.3/go.mod h1:naHLuLoDiP4jHNo9R0sCBMtWGeIprob74mVsIT4qYEQ=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
-github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
-github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
-github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
-github.com/stretchr/testify v1.8.2 h1:+h33VjcLVPDHtOdpUCuF+7gSuG3yGIftsP1YvFihtJ8=
-github.com/stretchr/testify v1.8.2/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
+github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
+github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
 github.com/t-tomalak/logrus-easy-formatter v0.0.0-20190827215021-c074f06c5816 h1:J6v8awz+me+xeb/cUTotKgceAYouhIB3pjzgRd6IlGk=
 github.com/t-tomalak/logrus-easy-formatter v0.0.0-20190827215021-c074f06c5816/go.mod h1:tzym/CEb5jnFI+Q0k4Qq3+LvRF4gO3E2pxS8fHP8jcA=
 github.com/urfave/cli/v2 v2.26.0 h1:3f3AMg3HpThFNT4I++TKOejZO8yU55t3JnnSr4S4QEI=