Create a large file with a given size with a pattern in Linux

Question

In Linux how can I create a large file with a given text or hex pattern (Like DEADBEEFDEADBEEFDEADBEEF ....)

I know dd can be used to create large files but it doesn't write desired text or hex pattern

dd if=/dev/urandom of=/tmp/bigfile bs=blocksize count=size

or

dd if=/dev/zero of=/tmp/bigfile bs=blocksize count=size

Quickly create a large file on a Linux system?

How to create a file with a given size in Linux?

score 7 · Accepted Answer · edited Mar 02 '20 at 20:18

7

while true ; do printf "DEADBEEF"; done | dd of=/tmp/bigfile bs=blocksize count=size iflag=fullblock

edited Mar 02 '20 at 20:18

Community

1
1

answered Dec 07 '17 at 17:08

Chirlo

5,989
1
29
45

1

Or `yes DEADBEEF | tr -d \\n | dd ...` – William Pursell Dec 07 '17 at 17:26
2

`while true ; do printf "\xDE\xAD\xBE\xEF"; done | dd of=/tmp/file bs=1c count=32` – katta Dec 07 '17 at 19:31

Srini V · Answer 2 · 2017-12-07T17:06:57.903

If your intention is to achieve a scrambled data and not random.

shuf folder/* | dd of=target.txt bs=1K count=2048

to get a 2MB sample file which you can then shorten or invoke the command above again with different numbers for count

folder/* will contain files with your patterns

Or as an alternative you can have your hexadecimal values stored in a single file in separate lines and use shuf to shuffle them based on your need and fill them

shuf -n 100 source.txt | dd of=target.txt bs=1K count=2048

Or you can just dump it in dd as

dd if=source.txt of=target.txt bs=1K count=2048

Shuffle Documentation

Sorry that did not work. source file had 4 bytes (DEADBEEF) – katta Dec 07 '17 at 17:58 — katta, Dec 07 '17 at 17:58

Create a large file with a given size with a pattern in Linux

2 Answers2