dash persistent input duplication like "exec 20<&0" is broken

[robinbryce]

Binary package hint: dash

dash 0.5.3-5ubuntu2
Ubuntu 7.04
Linux masham 2.6.20-16-generic #2 SMP Thu Jun 7 20:19:32 UTC 2007 i686 GNU/Linux

The following script, which Ian Jackson may recognize, fails at line 3

#!/bin/sh
set -e
exec 20<&0
exec 21<&1
exec 22<&2
exec 2>/dev/tty >&2
exec </dev/tty
program="$1"; shift

My reading of http://www.opengroup.org/onlinepubs/000095399/utilities/xcu_chap02.html (2.7.5) says "exec 20<&0" is leagal for a POSIX sh.

[robinbryce (robinbryce)]

The script works if 7,8,9 are used in place of 20,21,22. Is dash being overly pedantic with regard to "non portable" descriptors ?

[comotion (comotion)]

I have opened a new bug for the wider set of dash incompatabilites at https://bugs.launchpad.net/ubuntu/+source/dash/+bug/141481

[Daniel T Chen (crimsun)]

It may seem that dash is being overly pedantic, but it isn't a bug.

[Adam Buchbinder (adam-buchbinder)]

Closing as invalid, per Daniel T Chen's comment.