Function for the Plan 9 shell rc(1) to invoke a command with sh(1) and print out the specified environment variables in a form rc can read. I use rc for my shell but need to set up my environment like I was running sh.

eval-for-environ.rc

# eval-for-environ COMMAND [VARIABLE...]
# Evaluates COMMAND using sh then arranges for rc to learn the values
# of each of the environment variables VARIABLE.... This will break if
# the value of any VARIABLE may contain a quote (').
fn eval-for-environ{
	cmd=$1
	shift
	for(var){
		cmd=($cmd ';' echo $var'=\''"$(echo $'$var' | sed s/\''/\''\''/g)"\''')
	}
	echo $"cmd | sh
}

# Example:
# if(~ $#DBUS_SESSION_BUS_ADDRESS 0) {
#   eval `{eval-for-environ 'eval $(dbus-launch --exit-with-session)' DBUS_SESSION_BUS_ADDRESS DBUS_SESSION_BUS_PID}
# }