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On 1/11/13 1:27 PM, Dan Douglas wrote:
> Bash treats the variable as essentially undefined until given at least an
> empty value.
This is what Posix says:
A variable is a parameter denoted by a name.
A parameter is set if it has an assigned value (null is a valid
value). Once a variable is set, it can only be unset by using the
unset special built-in command.
A variable is unset until it has been assigned a value. Setting attributes
for a variable can change how it behaves when a value is assigned, but does
not assign a value itself, and the variable remains unset -- a simple
placeholder -- until it gets one. I know there are some inconsistencies in
how bash treats these `invisible' variables, but the above is the way
things are supposed to be.
Chet
- --
``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/
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