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Re: [Parameter substring expansion not work for negative offset]
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From: |
Greg Wooledge |
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Subject: |
Re: [Parameter substring expansion not work for negative offset] |
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Date: |
Mon, 9 Sep 2013 07:42:40 -0400 |
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User-agent: |
Mutt/1.4.2.3i |
On Sun, Sep 08, 2013 at 11:21:56AM -0500, Dennis Williamson wrote:
> The man page says "Note that a negative offset must be separated from the
> colon by at least one space..."
Enclosing the negative offset in parentheses also works.
The reason you must use either parentheses or spaces between them is
because ${parameter:-word} has another, completely different meaning.
${foo:-1}
will expand to the contents of `foo' if it is set and not empty, or the
literal string `1' otherwise.