ezpz

go.mod

@@ -0,0 +1,7 @@
+module strtime
+
+go 1.21.0
+
+require github.com/lestrrat-go/strftime v1.0.6
+
+require github.com/pkg/errors v0.9.1 // indirect

go.sum

@@ -0,0 +1,13 @@
+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=
+github.com/lestrrat-go/envload v0.0.0-20180220234015-a3eb8ddeffcc h1:RKf14vYWi2ttpEmkA4aQ3j4u9dStX2t4M8UM6qqNsG8=
+github.com/lestrrat-go/envload v0.0.0-20180220234015-a3eb8ddeffcc/go.mod h1:kopuH9ugFRkIXf3YoqHKyrJ9YfUFsckUU9S7B+XP+is=
+github.com/lestrrat-go/strftime v1.0.6 h1:CFGsDEt1pOpFNU+TJB0nhz9jl+K0hZSLE205AhTIGQQ=
+github.com/lestrrat-go/strftime v1.0.6/go.mod h1:f7jQKgV5nnJpYgdEasS+/y7EsTb8ykN2z68n3TtcTaw=
+github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
+github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.3.0 h1:TivCn/peBQ7UY8ooIcPgZFpTNSz0Q2U6UrFlUfqbe0Q=
+github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=

main.go

@@ -0,0 +1,35 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"time"
+
+	"github.com/lestrrat-go/strftime"
+)
+
+func main() {
+	in := flag.String("in", "2006-01-02T15:04:05", "input layout")
+	out := flag.String("out", "%s", "output layout (or strftime)")
+	flag.Parse()
+
+	formatter := func(t time.Time) string {
+		return t.Format(*out)
+	}
+	if pattern, err := strftime.New(
+		*out,
+		strftime.WithUnixSeconds('s'),
+		strftime.WithMilliseconds('L'),
+	); err == nil {
+		formatter = func(t time.Time) string {
+			return pattern.FormatString(t)
+		}
+	}
+	for _, flag := range flag.Args() {
+		t, err := time.ParseInLocation(*in, flag, time.Local)
+		if err != nil {
+			panic(err)
+		}
+		fmt.Println(formatter(t))
+	}
+}