ls and mv (partially) rewritten in go (without perf issues on directory with hundreds of thousands of files)

list.go

package main

import (
    "os"
    "log"
    "fmt"
)

func main() {
    dir, err := os.Getwd()
    if err != nil {
        log.Fatalf(err.Error())
    }

    if len(os.Args) > 1 {
        dir = os.Args[1]
    }

    f, err := os.Open(dir)
    if err != nil {
        log.Fatalf("Failed to open %s (err %d)", dir, err)
    }

    files, err := f.Readdirnames(-1)
    if err != nil {
        log.Fatalf("Failed to read entries in %s (err %d)", dir, err)
    }

    for _, file := range files {
        fmt.Println(file)
    }
}

move.go

package main

import (
    "os"
    "log"
    "fmt"
)

func main() {
    if len(os.Args) != 3 {
        log.Fatalf("Usage: %s <src> <dst>", os.Args[0])
    }

    src := os.Args[1]
    dst := os.Args[2]

    f, err := os.Open(src)
    if err != nil {
        log.Fatalf("Failed to open %s (err %d)", src, err)
    }

    files, err := f.Readdirnames(-1)
    if err != nil {
        log.Fatalf("Failed to read entries in %s (err %d)", src, err)
    }

    for _, file := range files {
        os.Rename(fmt.Sprintf("%s/%s", src, file), fmt.Sprintf("%s/%s", dst, file))
    }
}