Well, I found an ugly today. Nothing to do with FreeBSD, directly, just one of those pitfalls that you run into that is juicy:
expr '1' : '\(.*\)' returns "1", exit status of "0" expr '0' : '\(.*\)' returns "0", exit status of "1" expr 0 + 0 returns "0", exit status of "1" Why is this an error condition (I had this in a Makefile)? The pattern did match, and the addition did succeed, but the resulting string happened to be the string "0". Well, as the man page expr(1) does indicate that if the expression is an empty string or 0, a "1" is the exit code. Nobody said I have to like it. :) I've never been aware of this behavior of expr. I thought that I'd let you in on this little "problem" before, someday, you may run into it as well. Don't go around using expr to match the string "0", or to add numbers that sum up to 0. :) -Mark Taylor NetMAX Developer mtay...@cybernet.com To Unsubscribe: send mail to majord...@freebsd.org with "unsubscribe freebsd-hackers" in the body of the message
