Op 24-05-21 om 17:47 schreef Chet Ramey:
On 5/22/21 2:45 PM, Vincent Menegaux wrote:
Previously, these commands:
[[ ! 1 -eq 1 ]]; echo $?
[[ ! ! 1 -eq 1 ]]; echo $?
would both result in `1', since parsing `!' set CMD_INVERT_RETURN
instead of toggling it.
Interestingly, ksh93 produces the same result as bash. I agree that it's
more intuitive to toggle it.
Also interesting is that '!' as an argument to the simple 'test'/'['
command does work as expected (on both bash and ksh93): 'test ! ! 1 -eq
1' and '[ ! ! 1 -eq 1 ]' return 0/true.
Even the man page for [[ is identical for bash and ksh93:
| ! expression
| True if expression is false.
This suggests it's supposed to be a logical negation operator, i.e. '!'
is implicitly documented to negate another '!'. Bolsky & Korn's 1995 ksh
book, p. 167, is slightly more explicit about it: "! test-expression.
Logical negation of test-expression."
I also note that multiple '!' negators in '[[' work as expected on mksh,
yash and zsh.
So, it seems clear that this is an actual bug in bash and ksh. I see
it's been fixed in the bash devel tree now. I'll fix it in ksh 93u+m.
--
|| modernish -- harness the shell
|| https://github.com/modernish/modernish
||
|| KornShell lives!
|| https://github.com/ksh93/ksh
