Bug 1460926 - Indexing an Array in Bash is not working as expected
Indexing an Array in Bash is not working as expected
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: bash (Show other bugs)
Unspecified Unspecified
unspecified Severity unspecified
: rc
: ---
Assigned To: Siteshwar Vashisht
BaseOS QE - Apps
Depends On: 1392951
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Reported: 2017-06-13 03:39 EDT by Siteshwar Vashisht
Modified: 2017-06-19 10:27 EDT (History)
3 users (show)

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Clone Of: 1392951
Last Closed: 2017-06-19 10:27:33 EDT
Type: Bug
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Comment 2 Siteshwar Vashisht 2017-06-19 10:27:33 EDT
Anything between '[' and ']' is evaluated as a math expression. I will explain each command one by one :

'echo ${r[abc]}':

Here 'abc' will be replaced with 0, so it returns the 0th element from the array.

echo ${r[---abc]}:

Here math expression is evaluated as '-(--abc)'. Since 'abc' is 0, it will evaluate to '-(-1)' -> '1'. So it returns 1st element from array.

echo ${r[---abc]}:

It's the same as previous expression, but 'abc' is set to '-1' due to previous command. It will evaluate to '-(-2)' -> '2'. It returns empty element because array does not have a second element.

This is not a bug in bash.

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