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Powershell and writing files (how fast can you write to a file? )

  • Artigo

Hi there,

I’ve been working for some time on a tool similar to PAL from mike lagase in order to automate the analysis of loadgen runs.

While doing this I had to write large files with PowerShell and was not impressed with the result.

I thought I’d share the problem and solution with the community.

There are at least four ways of writing files with PSH:

· use the ‘>>’' alias that calls into the out-file cmd-let

· use export-csv

· use .Net

So let’s say I want to write 10000 lines into a file.

Method 1: use the >> operator

$s=”some text”

1..10000 | % {
$s >> ".\test.txt"
}

This way you actually open and close the file 1000 times.

Method 2: use out-file to write an Array

1..10000 | % {
$a+=[Array] $s
}

$a | out-file ".\test.txt"

This way actually writes once, using powershell.

Method 3: use export-csv to write an Array

$a=@()

1..10000 | % {

      $a+=[Array] $s

}

$a | export-csv "t.txt"

Export-csv can also write the array for you

Method 4: use .Net StreamWriter to write the file

$stream = [System.IO.StreamWriter] "t.txt"

1..10000 | % {

      $stream.WriteLine($s)

}

$stream.close()

The StreamWriter object from .Net also does the work nicely.

Conclusion: how fast ?

I tried all methods on my laptop, and here is what I got:

 Method

Time to completion

‘>>’

29 s

Outfile and [Array]

27 s

export-csv

22 s

StreamWriter

1.5 s

Well results speak by themselves, if you are in a hurry, use .Net StreamWriter !

Cheers,

Next, check that with Powerhell v2!

Guillaume

Comments

  • Anonymous
    January 01, 2003
    $b = 1..10000 $b | Out-File C:Temptemp.txt 2.3 seconds

  • Anonymous
    January 01, 2003
    Je viens de publier un petit post rapide sur la méthode d’écriture dans un fichier avec PSH : Powershell

  • Anonymous
    January 01, 2003
    Thank you for this. I'm using this in a function to continuously write the output from a serial port to a file

  • Anonymous
    May 06, 2009
    1 s with old school language : vbscript ;-)

  • Anonymous
    September 09, 2009
    Merci pour ce post, interessant surtout avec le temps d'execution, A+

  • Anonymous
    March 08, 2012
    @dak > file.txt doesn't accomplish the same thing

  • Anonymous
    March 30, 2013
    The comment has been removed

  • Anonymous
    May 09, 2013
    In your example for Stream Writer it does not output anything to the text file... You should have $_ in place of your $s Example: $stream = [System.IO.StreamWriter] "t.txt" 1..10000 | % {      $stream.WriteLine($_) } $stream.close()

  • Anonymous
    July 25, 2013
    @Marcus -- The four snippets actually belong in one file, that is why you see reuse of the $s variable in all 4 examples with only one definition in the first.  It would probably have been better to post the 4 examples as a single file, or post 4 complete files with all definitions needed included in each one.

  • Anonymous
    October 29, 2013
    The comment has been removed

  • Anonymous
    May 20, 2014
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  • Anonymous
    July 19, 2014
    only 0.08 sec with the funny language Batch

  • Anonymous
    September 10, 2014
    The comment has been removed

  • Anonymous
    May 28, 2015
    Thank you, I was looking for a simple means of generating output (wasn't remembering out-file) and found something even better.

  • Anonymous
    June 11, 2015
    I’ve been looking everywhere for this! Thank goodness I found it on Google. You have made my day!http://www.dietmythsandfacts.com/2013/10/old-school-new-body-user-reviews.html

  • Anonymous
    July 23, 2015
    thanks Streamwriter solved my issue for writing large dataset into text file, it's quite efficient and file size also is very compact

  • Anonymous
    August 06, 2015
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  • Anonymous
    November 15, 2015
    The comment has been removed

  • Anonymous
    February 11, 2016
    I googled this while I was inpatient, Streamwriter rocks! Thanks:)

  • Anonymous
    April 08, 2016
    The comment has been removed