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Re: Cygwin's vanilla sed : capabilities and limitations

On Wed, 16 Jul 2003 wrote:

> This is probably a cheat question (non-central Cygwin issue) but it is about
> Cygwin's vanilla sed.
> AND it is only asked in order eventually to provide anybody interested with
> the elegant-est possible script for making a portable Cygwin CD.

Someone already mentioned Perl.  Another tool is "ed".  Both are pretty
heavyweight.  If you want to do it in straight sed, examples are below:

> Q1. Querying info sed reveals the expression matcher to be "greedy",
> matching the longest possible string. Is there a way to make it match the
> shortest possible, so that echo aaabbbccc | sed 's/^.*b//' (altered but
> similar) grabs aaab not aaabbb?

Well, the simplest (off the top of my head) would be 's/^[^b]*b//'.

> Q2. Is there a way using the supplied sed without major enhancements to
> change "abc x def" to "def x abc": that is, to grab two distinct portions
> and swap them (using $1,$2 or \1,\2 or whatever).

Sure.  's/^\(.*\) x \(.*\)$/'.

> Sorry for asking: I know it's a sin: hope the end articulated above
> justifies the means.
> Fergus

Hope this helps,
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