a way to log to stdout and /var/log/jamf.log (or elsewhere) and have it match Jamf's log style

jamflog.function

# jamflog - Copyright (c) 2021 Joel Bruner, Licensed under the MIT License
# a way to log to stdout and /var/log/jamf.log (or elsewhere) and have it match Jamf's log style

##NOW MULTI-LINE an MULTI-MODE (parameter or PIPED)
function jamflog(){
	#unset xtrace if enabled to quiet this function
	[ -n "${-//[^x]/}" ] && { local xTrace=1; set +x; } &>/dev/null
	#take input either as a parameter or piped in
	if [ -n "${1}" ]; then local input="${1}"; elif [ ! -t '0' ]; then local input=$(cat); else return; fi
	#default destination is override-able
	local logFile="${2:-/var/log/jamf.log}"
	#if we cannot write to the log, unset and tee simply echoes
	([ -e "${logFile}" ] && [ ! -w "${logFile}" ]) && unset logFile
	#process each line
	local IFS=$'\n'
	for line in ${input}; do
		#this will tee to jamf.log in the jamf log format: <Day> <Month> DD HH:MM:SS <Computer Name> ProcessName[PID]: <Message>
		builtin echo "$(/bin/date +'%a %b %d %H:%M:%S') ${jamflog_myComputerName:="$(/usr/sbin/scutil --get ComputerName)"} ${jamflog_myName:="$(/usr/bin/basename "${0%.*}")"}[${myPID:=$$}]: ${line}" | /usr/bin/tee -a "${logFile}" 2>/dev/null
	done
	#re-enable xtrace if it was on
	[ "${xTrace:-0}" = 1 ] && { set -x; } &>/dev/null
}