[techtalk] Stumped by shell script

[Nancy Corbett]

You're the best!!  Um...it's stil not working perfectly, but I'm further
along than I was.  The input file is being read and it's substituting the
second and third variables perfectly.  The first one, however, within the
sed statement, is not returning the current date within the output file.
It's replacing DATE with "$1".  Where's it getting that?  Sheesh!

It's embarrassing to be so green at this...and to display it to you all.
But I'm having lots of fun (sick, huh?).

I'll keep hacking away at it.  Thank, thank you, thank you, Almut!

Nancy

On Tue, 29 May 2001, Almut Behrens wrote:

> On Mon, May 28, 2001 at 04:31:41PM -0700, Nancy Corbett wrote:
> > 
> > This is off topic, but I'm hoping your sharp eyes will see what I am
> > obviously missing.
> > 
> > I'm writing a ksh script which I want to give 3 variables and read them
> > from standard input.  To do this, I'm using sed.  I want sed to
> > change every instance of DATE to the current date in a given file
> > and rename the file to a different directory. 
> > 
> > Here's my script:
> > 
> > #!/bin/ksh 
> > 
> > sed 's/DATE/"$1"/g' "$2" > "$3"
> > exit 0;
> 
> I think you are just trying to do a bit too much at once... :)
> 
> Try something like:
> 
> #!/bin/ksh
> 
> read currdate
> read infile
> read outfile
> 
> eval "sed s/DATE/$currdate/g $infile > $outfile"
> 
> 
> The input.txt being (note there were two minor typos):
> 
> `date +%m-%d-%Y`
> FILE.05_24_2001.0529.CSV
> /path/to/newfile/FILE.`date +%H.%m_%d_%Y.%H%M`.CSV
> 
> 
> The problems with the original script were:
> 
> (a) standard input (redirected or not) is not being read
>     into the positional parameters $1, $2, etc. -- you need
>     'read' for that (with the added benefit that you can
>     choose readable variable names ;)
> 
> (b) the eval is required to expand the `date ...` commands
>     before executing the sed command
> 
> BTW, if you need quotes around the s/// (because of whitespace
> in the substitution string), you'd have to use double quotes
> like "sed \"s///\" ..."  (not 's///'),  or expand the $currdate
> before this line, e.g. using
> 
> eval "currdate=$currdate"
> 
> 
> Happy hacking!
> 
> - Almut
> 
> 
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