The process of creating a random file can be done in a number of ways: I’m going to create a 10M file using all commands to test this.

It can be done using the following 6 methods.

fallocate: fallocate is used to preallocate or deallocate space to a file. truncate: truncate is used to shrink or extend the size of a file to the specified size. dd: Copy a file, converting and formatting according to the operands. head: head is used to print the first part of files. xfs_mkfile: xfs_mkfile command allow us to create a specific size of a file in Linux. perl: Perl is a programming language specially designed for text editing.

Use dd

create a 100M file filled with all 0’s. $ dd if=/dev/zero of=100M_filled_with_zeros bs=100M count=1 create a 100M file filled with random data. $ dd if=/dev/urandom of=100M_filled_with_random_data bs=1M count=100

Use head

create a 100M file filled with all 0’s. $ head -c 100M /dev/zero > 100M_filled_with_zeros create a 100M file filled with random data. $ head -c 100M /dev/urandom > 100M_filled_with_random_data

Use openssl

openssl rand -out $testfile -base64 792917038; truncate -s-1 $testfile openssl rand -out myfile “$size” If you need base64: openssl rand -base64 -out myfile “$size”

Use jot

jot -r -c $FILESIZE > $FILE truncate –size 1G foo shred –iterations 1 foo

xfs_mkfile

xfs_mkfile 10M daygeek5.txt

For Strings

  1. Using the base64 Command $ base64 /dev/urandom | head –c 10 pIS3VBfRhf

$ base64 /dev/urandom | head –c 10 > random_file.txt $ cat random_file.txt /8ZtS5IfK+

  1. Using the tr Command

$ tr –dc [:graph:] < /dev/urandom | head –c 10 m1#Vs:ABp

$ tr –dc [:alnum:] < /dev/urandom | head –c 10 miB150lFw2

$ tr –dc [:graph:] < /dev/urandom | head –c 10 > random_file.txt $ cat random_file.txt TKt4r$#Z7r

  1. Using the strings Command

    $ strings -s “” /dev/urandom | head -c 10 BB2!C5./8 $ strings -s “” /dev/urandom | head -c 10 > random_file.txt $ cat random_file.txt 7)XM/F%F;^

  2. Using a Dictionary $ shuf -n 5 /usr/share/dict/words | tr ‘\n’ ‘ ‘ > random_file.txt $ cat random_file.txt