/dev/urandom | Cheatsheet

Populating files with random data

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Create several files filled with random data

for fileSize in 1 10 50 100 250 500 1000; do 
    echo "Creating file: ${fileSize}M"; 
    sudo head -c ${fileSize}M </dev/urandom >${fileSize}; 
done

Create a file with random data via openssl

head -c 50M </dev/urandom >50MB

Create a file with random data via openssl

openssl rand -out sample.txt -base64 $(( 2**30 * 3/4 ))

Create a file with random data via openssl

openssl rand -base64 1000 \
    |dd of=sample.txt bs=1G count=1

Create a file with random data via head

head -c 50M </dev/urandom >50MB

Create a file with random data via head

head -c 1073741824 </dev/urandom >myfile

Create a file with random data via fallocate

fallocate -l 100KB dummy_100KB_file

Create a file with random data via head

< /dev/urandom tr -dc "\t\n [:alnum:]" \ 
    | head -c1000 > file.txt

Resource(s)

• https://linuxgazette.net/153/pfeiffer.html
• https://unix.stackexchange.com/questions/33629/how-can-i-populate-a-file-with-random-data
• https://superuser.com/questions/470949/how-do-i-create-a-1gb-random-file-in-linux