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Re: `${PARAMETER:OFFSET}' does not work for negative offset
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From: |
Greg Wooledge |
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Subject: |
Re: `${PARAMETER:OFFSET}' does not work for negative offset |
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Date: |
Fri, 12 Feb 2016 08:29:03 -0500 |
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User-agent: |
Mutt/1.4.2.3i |
On Fri, Feb 12, 2016 at 09:22:21AM +0100, Ulrich Windl wrote:
> "X=ABC; echo ${X:-2}" outputs "ABC", and not "BC"
When using a negative index/offset, you have to separate it from the
colon so that it is not interpreted as a ${var:-default} substitution.
There are many ways to write it:
${x: -2}
${x:(-2)}
${x:0-2}
offset=-2; ${x:offset}
...
I prefer ${x:(-2)} myself, but they are all valid.