#!/bin/ash

[ "$#" -ne "1" ] && echo "Usage: $0 PID" && exit 1
[ ! -e "/proc/$1/environ" ] && echo "No such process: $1" && exit 1
[ ! -r "/proc/$1/environ" ] && echo "Cannot open process: $1" && exit 1
sed 's/\x0/\n/g' "/proc/$1/environ" | grep -E --color=auto '^[^=]*'