*export* all variables from key=value file to shell
Run set -a before sourcing the file. This marks all new and modified variables that follow for export automatically.
set -asource site.confset +a # Require export again, if desired.The problem you observed is that the pipe executes the export in a subshell. You can avoid that simply by using input redirection instead of a pipe.
while read assignment; do export "$assignment"done < site.confThis won't work, however, if (unlikely though it is) you have multiple assignments on one line, such as
EMAIL="dev@example.com" FULLNAME="Master Yedi"