random_data.sh

#!/bin/bash

# this file randomly creates and deletes files and directories on the
# production drive so our system can be tested over time.
# for each run of this script, a new file will be created containing a random
# number of bytes of random data. after this, there are four things that
# could happen:
# 1. this new file may be placed within a new directory
# 2. this new file may be placed within an existing directory
# 3. an existing file may be deleted
# 4. an existing directory may be deleted
# the "probabilities" of each of these options is defined at the beginning.
# USAGE: ./random_data.sh

DELDIR=7
DELFILE=6
PLACEDIR=4
NEWDIR=3

target_dir=/mnt/btrfs_project_drive/production/random
num=$RANDOM
numdirs=`find $target_dir/* -maxdepth 0 -type d | wc -l`
numfiles=`ls *.txt | wc -l`

# choose random directory within /random to delete, if we are deleting
if [ $numdirs -ne 0 ] && [ $(( $num % $DELDIR)) -eq 0 ] ;
then
    randomdir=$((RANDOM % numdirs))
    count=0
    
    # iterate through subdirectories within target to find the one to delete
    for dir in $target_dir/*/
    do
        dir=${dir%*/}
        if [ $count -eq $randomdir ]
        then
            rm -rf $dir
            break
        fi
        count=$((count+1))
    done
    
    numdirs=$((numdirs-1))
fi

# choose random file within /random to delete, if we are deleting
if [ $numfiles -ne 0 ] && [ $(( $num % $DELFILE)) -eq 0 ] ;
then
    randomfile=$((RANDOM % numfiles))
    count=0
    
    # iterate through files within target to find the one to delete
    for file in $target_dir/*.txt
    do
        if [ $count -eq $randomfile ]
        then
            rm $file
            break
        fi
        count=$((count+1))
    done
    
    numfiles=$((numfiles-1))
fi

# create a new directory, if we are creating
if [ $(( $num % $NEWDIR)) -eq 0 ]
then
    mkdir $target_dir/$num
    target_dir=$target_dir/$num
# choose random directory within /random to place file into, if we are placing
elif [ $numdirs -ne 0 ] && [ $(( $num % $PLACEDIR)) -eq 0 ] ;
then
    randomdir=$((RANDOM % numdirs))
    count=0
    
    # iterate through subdirectories to choose which one to place into
    for dir in $target_dir/*/
    do
        dir=${dir%*/}
        if [ $count -eq $randomdir ]
        then
            target_dir=$dir
            break
        fi
        count=$((count+1))
    done
fi

# create new file in target directory wtih random number of bytes
dd if=/dev/urandom bs=$((num/50)) count=4 > $target_dir/$num.txt