way to create file of specific size filled with nothing?

[Walleye]

how would i create a file of a specific size, filled with nothing but crap?

i got plans :evil:

 

[Walleye]

i suppose i could open up wordpad and hold down the "L" key for a long time, but that'd take too long.

 

[MikeMike]

friend once wrote a prgram to fill the drive, wrote a .txt file full of junk, in multiple locations until the drive was full. only worked on the c drive though
MIKE

 

[MustISO]

I have a program that does that. Basically creates padded files. There's nothing in them but the file system sees them as whatever size you specify. It's a simple command line utility.

 

[Bootprint]

Something like this might work for you.

 

[Walleye]

Originally posted by: nourdmrolNMT1
friend once wrote a prgram to fill the drive, wrote a .txt file full of junk, in multiple locations until the drive was full. only worked on the c drive though
MIKE

i dont have a C: drive.

i just want to make a file filled with a bunch of random crap for a length i specify in bytes.

 

[Walleye]

Originally posted by: Bootprint
Something like this might work for you.

well... i'm really trying to create 1 file of a specific length with nothing but crap inside. i'll manually edit in some file headers with wordpad or something. but beyond that, nothing but crap using every possible character on the keyboard.

 

[Mucman]

You could write a basic perl script to do this...

 

[Walleye]

i dont know perl.

i'm in my first semester of C++

 

[Mucman]

ok... you could easily do this in C++ then... it would only be a couple line perl script though. Only a couple of more lines if it's C++

 

[Beau]

It's slower than tar, but it works:
-------------------------------------------------------------------------------------------

N/M buggy. I'll fix it.

 

[glugglug]

cat /dev/random | head -c [number of bytes] > filename

cat /dev/zero | head -c [number of bytes] > filename also works if file full of zeros is ok.


or you could do this:

#include <ofstream>
#include <string>
using namespace std;

int main(int argc, char *argv[])
{
long numbytes = atol(argv[1]);
ofstream outfile(argv[2]);
outfile << string(numbytes,'X');
return 0;
}

 

[Beau]

fixed it. Make it into a vbs file (it's A LOT faster now, and you can use calculations in the input box like 1024^2 to make a 1 mb file.):
===========================
Sub Main()
     Dim intSize
     dblSize = CDbl(Eval(InputBox("How big do y'ant it? (in bytes)")) + 0)
     Continue = msgbox("Are you sure you want to create a " & dblSize & "b file?", vbOkCancel)
     If Continue = vbCancel Then Exit Sub

     Dim objFSO, objTextFile, strFileName
     Set objFSO = CreateObject("Scripting.FileSystemObject")

     Randomize
     
     Do While Len(strFileName) < 8
          strFileName = strFileName & Chr(Int((90 - 65 + 1) * Rnd + 65))
     Loop
     
     Set objTextFile = objFSO.CreateTextFile(strFileName & ".txt")
     
     Dim sTemp, i
     i = 0
     
     Do While i < dblSize
          i = i + 1
          sTemp = sTemp & (Chr(Int((254) * Rnd + 1)))
          if (i Mod(1000)) = 0 Then 'dump every 1000 characters
               objTextFile.Write(sTemp)
               sTemp = ""
          End if
     Loop
     
     objTextFile.Write(sTemp)

     Set objTextFile = Nothing
     Set objFSO = Nothing
     MsgBox("Finished.")
End Sub


Call Main

 

[Nothinman]

dd if=/dev/urandom of=/path/to/file bs=1024k count=10

That would give you a 10M file, adjust numbers as appropriate.

Or you could create a sparse file (100M this time) with dd if=/dev/urandom of=/path/to/file seek=100 count=1 bs=1M

 

[Walleye]

while this does exactly what i want, it makes an overflow error on the size files i'm trying to make.



i tried it on a 6000 kb file, and it worked.

but i'm trying to make a 700 mb + file, and it's giving a runtime error.

 

[Beau]

Originally posted by: Walleye
while this does exactly what i want, it makes an overflow error on the size files i'm trying to make.



i tried it on a 6000 kb file, and it worked.

but i'm trying to make a 700 mb + file, and it's giving a runtime error.

Try it now. I updated the code a bit. Does it actually start to run on the 700mb file? cuz it worked on mine. I let it go to about 60mb of the 700mb before I killed it.

also, what are you entering in fo rthe 700mb file. Should be 700 * (1024^2).

 

[Walleye]

Originally posted by: Beau

Originally posted by: Walleye
while this does exactly what i want, it makes an overflow error on the size files i'm trying to make.



i tried it on a 6000 kb file, and it worked.

but i'm trying to make a 700 mb + file, and it's giving a runtime error.

Try it now. I updated the code a bit. Does it actually start to run on the 700mb file? cuz it worked on mine. I let it go to about 60mb of the 700mb before I killed it.

also, what are you entering in fo rthe 700mb file. Should be 700 * (1024^2).

alright. now, yeah, it does work. i havent let it run for the 700 mb yet. for the test run i killed it at 30. but it looks like it's gonna work.

thanks

 

[Beau]

Originally posted by: Walleye

Originally posted by: Beau

Originally posted by: Walleye
while this does exactly what i want, it makes an overflow error on the size files i'm trying to make.



i tried it on a 6000 kb file, and it worked.

but i'm trying to make a 700 mb + file, and it's giving a runtime error.

Try it now. I updated the code a bit. Does it actually start to run on the 700mb file? cuz it worked on mine. I let it go to about 60mb of the 700mb before I killed it.

also, what are you entering in fo rthe 700mb file. Should be 700 * (1024^2).

alright. now, yeah, it does work. i havent let it run for the 700 mb yet. for the test run i killed it at 30. but it looks like it's gonna work.

thanks

No problem.

 

[PushHands]

$numbytes = 1024 # length of file in bytes
open JUNK, "<filename.junk";
for ($i = 0; $i < $numbytes; $i++){
print JUNK chr(0);
}
close JUNK;

That will create a file called "filename.junk" with the specified number of bytes, filled with 0s.

BTW, this is notfred posting from my friend's PC.