add env command

.gitignore

@@ -1,2 +1,4 @@
 ,
+commago
 *~
+.env*

env.go

@@ -0,0 +1,74 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"log"
+	"os"
+	"os/exec"
+	"strings"
+)
+
+var commandEnvDescription = "load environment variable from .env file"
+
+func commandEnv(args []string) {
+	var flagSet = flag.NewFlagSet("env", flag.ContinueOnError)
+	envFilePath := flagSet.String("file", ".env", "the file contains environment variables to parse")
+	printToScreen := flagSet.Bool("print", false, "wethear or not print to screen")
+	_ = printToScreen
+	printWithExport := flagSet.Bool("export", false, "wethear or not add `export` prefix to each variable when printing")
+	flagSet.Parse(args[1:])
+	_, err := parseEnvFileAndSetEnv(*envFilePath, *printToScreen, *printWithExport)
+	if err != nil {
+		fmt.Printf("%v", err)
+		os.Exit(2)
+	}
+	if len(flagSet.Args()) > 0 {
+		cmd := exec.Command(flagSet.Args()[0], flagSet.Args()[1:]...)
+		var out strings.Builder
+		cmd.Stdout = &out
+		err = cmd.Run()
+		if err != nil {
+			log.Fatal(err)
+		}
+		fmt.Printf(out.String())
+	}
+
+}
+
+func parseEnvFileAndSetEnv(filePath string, printToScreen, printWithExport bool) (string, error) {
+	raw, err := os.ReadFile(filePath)
+	if err != nil {
+		return "", fmt.Errorf("read from %v has error: %w", filePath, err)
+	}
+	rawLines := strings.Split(string(raw), "\n")
+	for i, line := range rawLines {
+		trimedLine := strings.TrimSpace(line)
+		if strings.HasPrefix(trimedLine, "#") {
+			continue
+		}
+		if trimedLine == "" {
+			continue
+		}
+		parts := strings.Split(trimedLine, "=")
+		if len(parts) != 2 {
+			return "", fmt.Errorf("line %v is malformed: `%v`", i+1, trimedLine)
+		}
+		if strings.TrimSpace(parts[0]) != parts[0] {
+			return "", fmt.Errorf("line %v is malformed: between variable name and `=` can't has any space", i+1)
+		}
+		if strings.TrimSpace(parts[1]) != parts[1] {
+			return "", fmt.Errorf("line %v is malformed: between `=` and value can't has any space", i+1)
+		}
+		os.Setenv(parts[0], parts[1])
+		if printToScreen {
+			s := fmt.Sprintf("%v=%v\n", parts[0], parts[1])
+			if printWithExport {
+				s = fmt.Sprintf("export %v", s)
+			}
+			fmt.Print(s)
+		}
+
+	}
+	return "", nil
+}

main.go

@@ -8,15 +8,24 @@ import (
 func commandsUsage() string {
 	return fmt.Sprintf(
 		`commands:
+  env         %v
   path        %v
-`, commandPathDescription)
+  time        %v
+  week        %v
+`, commandEnvDescription, commandPathDescription, commandTimeDescription, commandWeekDescription)
 }
 
 func main() {
 	if len(os.Args) >= 2 {
 		switch os.Args[1] {
+		case "env":
+			commandEnv(os.Args[1:])
 		case "path":
 			commandPath(os.Args[1:])
+		case "time":
+			commandTime(os.Args[1:])
+		case "week":
+			commandWeek(os.Args[1:])
 		default:
 			fmt.Printf("unknow command `%v`\n\n", os.Args[1])
 			fmt.Printf("%v", commandsUsage())

time.go

@@ -0,0 +1,48 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"strconv"
+	"time"
+)
+
+var commandTimeDescription = "display more information about target timestamp/time"
+
+func commandTime(args []string) {
+	var err error
+	targetTime := time.Now()
+	if len(args) > 1 {
+		targetTime, err = time.Parse(time.RFC3339, args[1])
+		if err == nil {
+			goto GOTTIME
+		}
+		if len(args[1]) <= 10 {
+			var unix int
+			unix, err = strconv.Atoi(args[1])
+			if err != nil {
+				fmt.Printf("`%v` is not a Unix Epoch Time\n", args[1])
+				os.Exit(1)
+			}
+			targetTime = time.Unix(int64(unix), 0)
+		} else if len(args[1]) >= 13 {
+			var unixMilli int
+			unixMilli, err = strconv.Atoi(args[1])
+			if err != nil {
+				fmt.Printf("`%v` is not a Unix Epoch Time in milliseconds\n", args[1])
+				os.Exit(1)
+			}
+			targetTime = time.UnixMilli(int64(unixMilli))
+		} else {
+			fmt.Printf("`%v` is neighter a Unix Epoch Time, nor a formatted time in ISO8601", args[1])
+			os.Exit(1)
+		}
+
+	}
+GOTTIME:
+	fmt.Printf("Unix:               %v\n", targetTime.Unix())
+	fmt.Printf("Unix milliseconds:  %v\n", targetTime.UnixMilli())
+	fmt.Printf("Local time:         %v\n", targetTime.Local().Format(time.RFC3339))
+	fmt.Printf("UTC time:           %v\n", targetTime.UTC().Format(time.RFC3339))
+	fmt.Printf("Time to target:     %v\n", targetTime.Sub(time.Now()))
+}

week.go

@@ -0,0 +1,36 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"strconv"
+	"time"
+)
+
+var commandWeekDescription = "get week in this year and week begin and end offset by this week"
+
+func commandWeek(args []string) {
+	var err error
+	offset := 0
+	if len(args) == 2 {
+		offset, err = strconv.Atoi(args[1])
+		if err != nil {
+			fmt.Printf("expect `%v` to be a integer\n", args[1])
+			os.Exit(1)
+		}
+	} else if len(args) > 2 {
+		fmt.Printf("only accept 1 argument, got %v\n", len(args)-1)
+		os.Exit(1)
+	}
+	offsetTime := time.Hour * time.Duration(offset) * 7 * 24
+	targetTime := time.Now().Add(offsetTime)
+	_, week := targetTime.ISOWeek()
+	weekday := int(targetTime.Weekday())
+	// make Sunday = 7
+	if weekday == 0 {
+		weekday = 7
+	}
+	weekBegin := targetTime.Add(time.Hour * 24 * time.Duration(weekday-1) * -1)
+	weekEnd := targetTime.Add(time.Hour * 24 * time.Duration(7-weekday))
+	fmt.Printf("week-%v-%v-%v\n", week, weekBegin.Format("0102"), weekEnd.Format("0102"))
+}