Why don't you use the expand_template method for file editing?
M
Jesse Becker wrote:
> On Tue, Mar 02, 2010 at 08:33:15AM -0500, nwat...@symcor.com wrote:
>> I don't think there is a function at present for string search a replace
>> actions out side of file editing. Perhaps look at it from a higher level.
>> Why is string manipulation needed?
>
> There are two reasons, one specific, and one general.
>
> The specific reason is that I am trying to build a somewhat more robust
> template library (which if I ever get to work, I will post to the list).
>
> To do this, I am trying to convert a file from the form of
> "/some/path/to/file" into something like
> "/path/to/repo/_some_path_to_file".
>
> This is trivial with two regexes. Using quasi-cfengine notation, and
> a hypothetical regreplace(string,find,replace) function, something like
> this would work:
>
> vars:
> "orig" = "/some/path/to/file";
> "new" = regreplace(
> regreplace("${orig}", "/", "_" ),
> "^",
> "/path/to/repo"
> );
>
>
>
> The general reason is that string search and replace is a very useful
> tool. It doesn't really matter the what the specific problem actually
> is, since this is a more general issue. A good tool is useful in lots
> of different situations, including those in which it was not originally
> intended.
>
> There have been several occasions where a simple string replacement would
> make certain promises simpler, but I have attempted to work around them.
> But having to shell out and make two calls to outside binaries--one
> of them being echo!--just to do a simple string manipulation seems
> counter-productive, inefficient, and much more error prone (especially
> due to the hazards of shell quoting).
>
> Here's another example, albeit slightly contrived. You have a system
> where you want to start hashing user home directories in the form of
> "jbecker -> /home/j/jbecker" (for example). Based on some
> list of users, there is a set of promises to ensure that the accounts
> exist, including calling 'useradd'. Having a short set of promises to
> convert the string "jbecker" into "/home/j/jbecker" is fairly easy using
> a search and replace function. I can envision a situation where
> cfengine could actually handle the migration of existing "unhashed" user
> home directories to "hashed" ones, but only if it supports better string
> handling routines.
>
> Of course, one can always just hand off a username to a Perl script as
> well.
>
> I really want is a general solution (which is why I did not simply ask
> how to munge a path). Once I--and everyone else--has that, the
> specifics should be simple. :)
>
>
>
--
Mark Burgess
-------------------------------------------------
Professor of Network and System Administration
Oslo University College, Norway
Personal Web: http://www.iu.hio.no/~mark
Office Telf : +47 22453272
-------------------------------------------------
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