Create file of size x

Improve this question. Questioneer Questioneer 4 4 gold badges 12 12 silver badges 19 19 bronze badges. Look at the answer of stackoverflow. Add a comment. Active Oldest Votes.

Improve this answer. Daniel Jour Adrian Cornish Adrian Cornish That's 8 times as large as 8Mb. Plus one byte. I can't think of one. But you stated that the file will be 1Mb when instead it will actually be 1MB. Ignacio Vazquez-Abrams And really it did not account to you that the typo between 'b' and 'B' was more likely than the scenario of me providing a solution in MeagBits. Mb MB and MiB all mean different things. This example creates a file of size 1 MiB.

Not 1MB or 1Mb. Show 5 more comments. Community Bot 1 1 1 silver badge. Somebody did , two years before you. Upvoted anyway, though. Truncating an existing file is easy in Unix variants, anyway -- use the truncate function.

I'd like set the size of a file. Sorry, I still don't get it - when I asked you to clarify what you mean by "how do I set the size of the file" you repeated "I'd like to set the size of the file. Sorry for the vague response — Questioneer. Questioneer: What exactly do you mean by "empty"?

Normally, a file with a non-zero size is not empty. This creates a file full of null bytes. If the file already exists and is smaller, it is extended to the requested size with null bytes. If the file already exists and is larger, is is truncated to the requested size. The null bytes do not consume any disk space, the file is a sparse file. Obviously, using dd for a 24MB file won't take any time on a modern system, but larger files can be noticeably slow.

Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. Generate File of a certain size? Ask Question. Asked 8 years, 2 months ago. Active 1 month ago. Viewed k times. I'd like to generate a file with the name example. I could use touch example. Improve this question.

Gilles 'SO- stop being evil' k gold badges silver badges bronze badges. We will all assume you do not care what the content is so filled with zeroes will be fine.

Add a comment. We can create a file of required size using this tool. Note that the above command creates a sparse file which does not have any real data. If you want to create a file with real data then you can use the below command line script. The above commands create a 1 MB file dummy.

If you want to create 1 GB file you need to change the second command as below. Explanation: The first command echo… creates the file dummy. The second command, runs in a loop for 24 times, and each times doubles the size of the file, by appending it to itself. One more example:. That for loop is nice trick to create big files..

Thanks for sharing. If you increase the bold number by 1, you can double the size of the file. If you decrease it by 1 you will reduce the file size by half. Would you please explain how this calculated? Would you please shed some light on this calculation? Answers: 1. The script initially writes the text specified in the command to the file. And each time the type command appends the file content in dummy. So the size of the file doubles with each iteration. So if you decrease the number of characters in the initial file, automatically the size of the final file will also be lesser.

However, the file size never grow greater than 4GB. I thought it might be a Windows limitation so I used another tool to create the GB file. That tool successfully created the big GB file. Maybe this append file method has a limitation at 4GB? Its maximum file size is 4GB, so the file more than 4 GB will not be created. Is there a way to loop it to make a multiple large files? You can do that. First create a file with the above commands and then create required number of files using copy command.

For anyone putting the command into a batch file you need to use double percentages to make it work, eg,. Hi Great little article. For example, if you are a system administrator and are deploying a new file replication software, you may want to evaluate the software if it works for all scenarios. For this, you can create files of varying sizes and test the software before the actual deployment.

This will create a highly compressible file since the same data is repeated over and over. Also if you want to do performance testing, caching could skew your results if its the same bits being loaded over and over. Can some explain this please step by step:. I am not understanding those numbers.