Bash history backup script

backup-history.sh

#!/bin/bash --login
# Make a backup of the user's Bash history

if [ -z "${HISTFILE}" ]; then
	cd "${HOME}"
	hfile='.bash_history'
else
	cd "${HISTFILE%/*}"
	hfile="${HISTFILE##*/}"
fi

if [ -f "${hfile}" ]; then
	hsize=$(stat -c '%s' "${hfile}")
	bfile="${hfile}~"
elif [ -e "${hfile}" ]; then
	echo "${PWD}/${hfile} is not a regular file. Aborting." >&2
	exit 1
else
	echo "${hfile} not found in ${PWD}. Aborting." >&2
	exit 1
fi

if [ -f "${bfile}" ]; then
	bsize=$(stat -c '%s' "${bfile}")
elif [ -e "${bfile}" ]; then
	echo "${PWD}/${bfile} is not a regular file. Aborting." >&2
	exit 1
else
	bsize=0
fi

if [ ${bsize} -gt ${hsize} ]; then
	echo "Backup is larger than current history. Aborting." >&2
	exit 1
fi

cp -fp "${hfile}" "${bfile}"

If you value your history, call this from your personal crontab.