On 6/17/15 6:33 PM, Nick Stoughton wrote: > I was surprised when the following script did NOT exit at the indicated line: > > set -e > export X=$(false) > # should not reach here > echo did not exit > > Similarly, this fails in the same way: > > set -e > X=$(false) export X > # should not reach here > echo did not exit
Neither of these are failures; the export command returns success. In fact, according to Posix, the export command cannot fail. > while, conversely, this did exit as expected and exited on error: > * > * > set -e > X=$(false) > # should not reach here > export X > echo did not exit Because http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_09_01 calls it out as a special case. > The export utility is a special built-in, and according to POSIX XCU 2.8.1 > "Consequences of Shell Errors", special built-ins should exit (with a > diagnostic message) on both variable assignment error and expansion error. This is neither a variable assignment error (the variable is correctly assigned the output of the command substitution) nor an expansion error (the command substitution is well-formed). -- ``The lyf so short, the craft so long to lerne.'' - Chaucer ``Ars longa, vita brevis'' - Hippocrates Chet Ramey, ITS, CWRU c...@case.edu http://cnswww.cns.cwru.edu/~chet/
