# jail -c persist osrelease="$(echo major=1; echo minor=0)" # jls JID IP Address Hostname Path 145 / # jls osrelease jid major=1 minor=0 145 the manpage clearly states: Each jail is represented by one row which contains space-separated values of the listed parameter Either we should amend the manpage, or swap newlines for spaces consistently on all parameters. It seems that a trailing newline is removed, so perhaps for consistency we should replace all newlines with space when this single-line output is used.