Replace flag with zflag.

README.md

@@ -21,43 +21,27 @@ go install github.com/stefansundin/s3sha256sum@latest
 ## Usage
 
 ```
-$ s3sha256sum -help
+$ s3sha256sum --help
 Usage: s3sha256sum [parameters] <S3Uri> [S3Uri]...
 S3Uri must have the format s3://<bucketname>/<key>.
 
 Parameters:
-  -ca-bundle string
-    	The CA certificate bundle to use when verifying SSL certificates.
-  -debug
-    	Turn on debug logging.
-  -endpoint-url string
-    	Override the S3 endpoint URL. (for use with S3 compatible APIs)
-  -expected-bucket-owner string
-    	The account ID of the expected bucket owner.
-  -no-sign-request
-    	Do not sign requests.
-  -no-verify-ssl
-    	Do not verify SSL certificates.
-  -paranoid duration
-    	Print status and hash state on an interval. (e.g. "10s")
-  -profile string
-    	Use a specific profile from your credential file.
-  -region string
-    	The region to use. Overrides config/env settings. Avoids one API call.
-  -request-payer string
-    	Confirms that the requester knows that they will be charged for the requests. Possible values: requester.
-  -resume string
-    	Provide a hash state to resume from a specific position.
-  -use-accelerate-endpoint
-    	Use S3 Transfer Acceleration.
-  -use-path-style
-    	Use S3 Path Style.
-  -verbose
-    	Verbose output.
-  -version
-    	Print version number.
-  -version-id string
-    	Version ID used to reference a specific version of the S3 object.
+      --ca-bundle string               The CA certificate bundle to use when verifying SSL certificates.
+      --debug                          Turn on debug logging.
+      --endpoint-url string            Override the S3 endpoint URL. (for use with S3 compatible APIs)
+      --expected-bucket-owner string   The account ID of the expected bucket owner.
+      --no-sign-request                Do not sign requests.
+      --no-verify-ssl                  Do not verify SSL certificates.
+      --paranoid duration              Print status and hash state on an interval. (e.g. "10s")
+      --profile string                 Use a specific profile from your credential file.
+      --region string                  The region to use. Overrides config/env settings. Avoids one API call.
+      --request-payer string           Confirms that the requester knows that they will be charged for the requests. Possible values: requester.
+      --resume string                  Provide a hash state to resume from a specific position.
+      --use-accelerate-endpoint        Use S3 Transfer Acceleration.
+      --use-path-style                 Use S3 Path Style.
+      --verbose                        Verbose output.
+      --version                        Print version number.
+      --version-id string              Version ID used to reference a specific version of the S3 object.
 ```
 
 You can also set environment variables that [aws-sdk-go-v2](https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/config#EnvConfig) automatically consumes:

go.mod

@@ -6,6 +6,7 @@ require (
 	github.com/aws/aws-sdk-go-v2 v1.16.11
 	github.com/aws/aws-sdk-go-v2/config v1.17.1
 	github.com/aws/aws-sdk-go-v2/service/s3 v1.27.5
+	github.com/stefansundin/go-zflag v1.1.1
 )
 
 require (

go.sum

@@ -38,6 +38,8 @@ github.com/google/go-cmp v0.5.8/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeN
 github.com/jmespath/go-jmespath v0.4.0/go.mod h1:T8mJZnbsbmF+m6zOOFylbeCJqk5+pHWvzYPziyZiYoo=
 github.com/jmespath/go-jmespath/internal/testify v1.5.1/go.mod h1:L3OGu8Wl2/fWfCI6z80xFu9LTZmf1ZRjMHUOPmWr69U=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stefansundin/go-zflag v1.1.1 h1:XabhzWS588bVvV1z1UctSa6i8zHkXc5W9otqtnDSHw8=
+github.com/stefansundin/go-zflag v1.1.1/go.mod h1:HXX5rABl1AoTcZ2jw+CqJ7R8irczaLquGNZlFabZooc=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v2 v2.2.8/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=

main.go

@@ -7,7 +7,6 @@ import (
 	"encoding/base64"
 	"encoding/hex"
 	"errors"
-	"flag"
 	"fmt"
 	"hash"
 	"io"
@@ -24,6 +23,7 @@ import (
 	"github.com/aws/aws-sdk-go-v2/credentials/stscreds"
 	"github.com/aws/aws-sdk-go-v2/service/s3"
 	s3Types "github.com/aws/aws-sdk-go-v2/service/s3/types"
+	flag "github.com/stefansundin/go-zflag"
 )
 
 const version = "0.1.0"
@@ -76,10 +76,11 @@ func main() {
 	if versionFlag {
 		fmt.Println(version)
 		os.Exit(0)
-	}
-	if flag.NArg() == 0 {
+	} else if flag.NArg() == 0 {
 		flag.Usage()
-		os.Exit(0)
+		fmt.Fprintln(os.Stderr)
+		fmt.Fprintln(os.Stderr, "Error: At least one S3Uri parameter is required!")
+		os.Exit(1)
 	}
 
 	if endpointURL != "" {

utils.go

@@ -44,9 +44,9 @@ func formatFilesize(size uint64) string {
 }
 
 func formatResumeCommand(encodedState, arg string) string {
-	cmd := []string{os.Args[0], "-resume", encodedState}
+	cmd := []string{os.Args[0], "--resume", encodedState}
 	for i := 1; i < len(os.Args); i++ {
-		if os.Args[i] == "-resume" {
+		if os.Args[i] == "--resume" {
 			i++
 			continue
 		}