[CLUE-Tech] bash question

[Keith Hellman]

Does anyone know how to determine if bash environmental variable exists?

Note, I know of ( test -z "${VAR}" ); but this doesn't tell me if the var
EXISTS, it just tells me if it expands to a non-empty string.

I could do ( set |grep VAR >/dev/null ); test $?
but this requires an invokation of grep, which seems wasteful.

readonly does not return an error value when VAR does not exist.

I could write an external program to inspect the environment, but this
would only detect exported vars; it also has the same downside of grep...

It seems strange that this simply query is not available - I must be
missing something in the docs.

I'm twiddling with the set builtin now - I think I can coerce it into a
valid test...

The upside is that I have to scan the docs well, so I keep finding bash
features I always wished I had :^)

TIA


=====
Keith E. Hellman
kehellman at yahoo.com

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