command to create file with certain size

[Frank de Vries]

I forgot which command (not touch) you can create a file with a certain size

[Elmar P. Kolkman]

dd is your friend:
dd of= bs=1024 count= if=/dev/zero

[Frank de Vries]

dd may do the trick, however I was looking for a different command.

[Robert-Jan Goossens · Accepted solution]

Hi,

You can create a file with prealloc,

# prealloc file 10000000 ( 10 mb)

Hope it helps,

Robert-Jan.

[Frank de Vries]

That's then one, full marks !

[Elmar P. Kolkman]

You can do it different too, but to create a sparse file. In C it will look like below. Of course things like parameter checking etc. are necessary if you really want to use this...
--- ---
#include
#include

void main(int argc,char **argv)
{
int fd=open(argv[1],O_WRONLY|O_CREAT);
lseek(fd,atoi(argv[2]),SEEK_SET);
close(fd);
}