Re: IFS File Update

[Scott Klement <rpg400-l@xxxxxxxxxxxxxxxx>]

Vern,

This can be a good solution if the circumstances are right.  However, I 
think it's worth noting two things:

1) sed has no knowledge of XML syntax.  So you need to be careful that 
what you find/replace doesn't break the XML document... (Just as Henrik 
pointed out.)

2) This method will translate all data into EBCDIC when reading the 
file, and translate back to UTF-8 when writing the file back out.  If 
you have any UTF-8 characters that don't exist in your job's EBCDIC 
CCSID, then the results will not be satisfactory.

If neither of these are a problem in your particular instance, however, 
this can be a good solution.

-SK


On 9/2/2014 11:28 AM, Vernon Hamberg wrote:
> Michael
>
> You should look at using the sed function in QShell - it has a
> substitute option that lets you do exactly what you want. Making the
> change in place requires a couple dance steps, but it's not too hard -
> see example below.
>
> It can be set to replace only the first instance, or all instances of
> the search string - so you may need something unique to search for -
> depends on what you need to do.
>
> It CAN also be set to look only within a range or lines (delimited by
> CRLF or the like).
>
> Here is an example using the qsh command -
>
> qsh cmd('export QIBM_CCSID=1208 && sed
> "firstlinetosearh,lastlinetosearch s/searchstring/replacestring/g"
> ifsfilepath > temp.tmp && mv temp.tmp ifsfilepath')
>
> I am writing to an XML file, so I set the CCSID for QShell to UTC-8 -
> that is because the redirect in QShell uses the job CCSID, which would
> be 37, of course, usually.
>
> The double ampersands are command separators - if a command fails, the
> whole thing stops - so if the export fails, the sed and mv are not
> executed - if sed fails, mv is not executed.
>
> The lines to search are optional, if you want to search the entire IFS
> file, but they help if you know the range where the value-to-replace is
> located. There are some other ways to delimit the search range, I believe.
>
> The "g" right after "replacestring/" means greedy, IIRC - it makes sed
> replace every instance of the search string.
>
> The > redirects output to another IFS file. You can't redirect to the
> one you are reading from.
>
> Finally, the mv command (move) takes temp.tmp and overwrites it to the
> IFS file.
>
> I'm using it now - works very well.
>
> There IS an option in other version of sed that let you do an in-place -
> maybe the version in PASE can do that - then you would have different
> CCSID questions, etc.
>
> HTH
> Vern
>
> On 9/2/2014 10:02 AM, Michael Ryan wrote:
> > I need to update data in a stream file located in ths IFS (or on a QNTC
> > share). I know I can read the data from the file, and then write to
> > another
> > file, and then delete/rename I guess, but I want to update in place. I
> > don't want to use any procedures that add a CRLF. I'm thinking of using
> > read() and write(), but I'm not sure how to handle the update. Probably
> > pretty simple. Thanks!