usage.go

package utils

import "fmt"

func main() {
  for line := range FileLineChannel('/etc/hosts') {
    fmt.Println(line)
  }
}

utils.go

package utils

import (
  "log"
  "bufio"
  "io"
  "os"
)

func FileLineChannel(fpath string) (<-chan string) {
  c := make(chan string)
  
  go func(fpath string, cs chan<- string) {
    defer close(cs)
    file, err := os.Open(fpath)
    if err == nil {
      defer file.Close()
      buf := bufio.NewReader(file)

      for {
       line, err := buf.ReadString('\n')
       switch err {
       case io.EOF: break
       case nil: cs <- line
       default: log.Fatal(err)
       }
      }
    }
  }(fpath, c)

  return c
}

I think you need to move the cs <- line above your switch as otherwise if the file ends without a newline, you won't send the last line into your channel. (the case io.EOF will hit first).