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Evolution of shells in Linux (developerWorks)Evolution of shells in Linux (developerWorks)Posted Dec 9, 2011 19:31 UTC (Fri) by HelloWorld (guest, #56129)In reply to: Evolution of shells in Linux (developerWorks) by mathstuf Parent article: Evolution of shells in Linux (developerWorks)
> It's a string, not an array (indexing strings works here in bash).
It certainly doesn't work with the syntax you've shown, as that is the syntax for array subscription.
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Evolution of shells in Linux (developerWorks) Posted Dec 9, 2011 20:09 UTC (Fri) by nybble41 (subscriber, #55106) [Link]
Technically it *will* work, but only because the value of the variable is output in the first iteration of the loop, and the following iterations have no effect (${var[1..N]} are empty). I.e., aside from the obvious inefficiency, the entire loop is equivalent to:
echo -n "$var"
To work as intended the variable reference would need to use substring syntax, "${var:$x:1}", rather than the array syntax "${var[$x]}". However, it is sufficient to place the variable in double-quotes, which (in bash) causes the value to be output verbatim, with no further quoting, expansion, or splitting.
Evolution of shells in Linux (developerWorks) Posted Dec 9, 2011 20:13 UTC (Fri) by HelloWorld (guest, #56129) [Link]
> Technically it *will* work, but only because the value of the variable is output in the first iteration of the loop,
No, the loop starts at 1 instead of 0.
Evolution of shells in Linux (developerWorks) Posted Dec 9, 2011 20:25 UTC (Fri) by nybble41 (subscriber, #55106) [Link]
Hm. You're right, which is strange since both arrays and characters are zero-indexed (except for $@). Perhaps that loop was written for a different shell entirely? It's certainly not necessary in reasonably modern implementations (i.e. within the last decade) of bash.
Evolution of shells in Linux (developerWorks) Posted Dec 10, 2011 3:34 UTC (Sat) by mathstuf (subscriber, #69389) [Link]
Nope, I was a typo. Somehow I missed that it just printed something on the first iteration, and nothing on the rest... Not sure how I forgot about printf either.
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