dell:~/Documents/nim/write_bench/src$ cat main_nim.nim
import times

let time = cpuTime()
let f = open("test_nim.txt", fmWrite)

var data: string
for i in 0..1000_000:
  data.add("line ")
  data.add($i)
  data.add("\n")

f.write(data)
f.close()
echo "Time taken: " & $((cpuTime() - time)*1000.0'f32) & "ms"
dell:~/Documents/nim/write_bench/src$ nim c -d:release --gc:markandsweep -r ../src/main_nim.nim
Hint: used config file '~/.choosenim/toolchains/nim-1.0.0/config/nim.cfg' [Conf]
Hint: operation successful (300 lines compiled; 0.046 sec total; 6.004MiB peakmem; Release Build) [SuccessX]
Hint: ~/Documents/nim/write_bench/src/main_nim  [Exec]
Time taken: 142.021312ms
dell:~/Documents/nim/write_bench/src$
dell:~/Documents/nim/write_bench/src$ cat main_nim.nim
import times

proc main() =
  let time = cpuTime()
  let f = open("test_nim.txt", fmWrite, high(cint))

  const l = "line "
  for i in 0..1_000_000:
    f.write(l)
    f.writeLine($i)

  f.close()
  echo "Time taken: " & $((cpuTime() - time)*1000.0'f32) & "ms"

main()
dell:~/Documents/nim/write_bench/src$ nim cpp -d:release --gc:markandsweep -r ../src/main_nim.nim
Hint: used config file '~/.choosenim/toolchains/nim-1.0.0/config/nim.cfg' [Conf]
Hint: system [Processing]
Hint: widestrs [Processing]
Hint: io [Processing]
Hint: main_nim [Processing]
Hint: times [Processing]
Hint: strutils [Processing]
Hint: parseutils [Processing]
Hint: math [Processing]
Hint: bitops [Processing]
Hint: macros [Processing]
Hint: algorithm [Processing]
Hint: unicode [Processing]
Hint: options [Processing]
Hint: typetraits [Processing]
Hint: posix [Processing]
CC: stdlib_system.nim
CC: main_nim.nim
Hint:  [Link]
Hint: operation successful (31955 lines compiled; 2.349 sec total; 56.883MiB peakmem; Release Build) [SuccessX]
Hint: ~/Documents/nim/write_bench/src/main_nim  [Exec]
Time taken: 152.028969ms