Example to create an exclusive temp/working dir in bash. Based on the atomicity of mkdir.

mktmpdir.sh

#!/bin/bash
# create an exclusive temp dir
# allow bash-isms
# b.kenyon.w@gmail.com

# If you don't need to retain the temp files after execution, and you reliably
# clean up on exit with a trap, and you only need to worry about concurrent
# instances, then you can just use $$ cheaper instead of this "until mkdir" loop.

# Comment this out to retain the temp files after execution (logging, debugging)
trap '[[ -d "$x" ]] && rm -rf "$x"' EXIT

# This allows unlimited calls per second, safely with no collsions.
# No 2 instances will ever produce the same temp name no matter
# how many instances all try simultaneously.
_mktmpd () {
	MKTMPD="${1:-$MKTMPD}"
	local b="${MKTMPD:-/tmp/${0//\//_}}" ;local p="${b%/*}"
	[[ -d "$p" ]] || { mkdir -p "$p" ;[[ -d "$p" ]] || exit 1 ; }
	n=0 MKTMPD="${b}_00000000"
	until mkdir "$MKTMPD" ;do printf -v MKTMPD '%s_%08d' "$b" $((++n)) ;done
}

# Optionally specify a base path in MKTMPD, or as an argument.
# This example creates a base path of /tmp/${APP_NAME}/YYYY/MM/DD/HH/MMSS
# which facilitates retaining the work files as a form of logging.
# Final temp dir name will be ex: "/tmp/foo/2021/08/13/15/4403_00000001/"
APP_NAME=foo
printf -v MKTMPD '/tmp/%s/%(%Y/%m/%d/%H)T' "${APP_NAME}" -1

_mktmpd

# Dir is created and the name of the created dir is in $MKTMPD
echo "Created \"${MKTMPD}\""