Write random data to disk

write-random-data

#!/bin/sh

set -euo pipefail

if [[ $# -lt 1 || $1 == "--help" ]]; then
    echo "Usage: $0 <target_path> <size_in_gb> (default: 10)"
    exit 0
fi

GiB_IN_BYTES=1073741824
TARGET_PATH=${1:-"/tmp/random"}
SIZE_IN_GB=${2:-"10"}

mkdir -p "${TARGET_PATH}"
echo "Begining to write ${SIZE_IN_GB} GiB of random data to ${TARGET_PATH}"
start_time=`date +%s`
for i in `seq 1 ${SIZE_IN_GB}`
do
    file_name=`LC_ALL=C tr -dc A-Za-z0-9 < /dev/urandom | head -c 8 || true`
    target_file="${TARGET_PATH}/${file_name}.dat"
    echo "Writing ${i} of ${SIZE_IN_GB} GiB to ${target_file}"
    head -c "$GiB_IN_BYTES" < /dev/urandom > "${target_file}"
done

echo "${SIZE_IN_GB} GiB of random data written to ${TARGET_PATH} in `expr $(date +%s) - ${start_time}`s."