Conference turris::digital_unix

The script in .0 works (echoes 'date') on Solaris, HPUX
and AIX, but not on dUNIX 3.2d-1 or 4.0b.

Here's another script with problems.

Should echo:         /usr/products/ftt/v1_5
but instead outputs: $FTT_DIR

It works ok on dUNIX 3.2D-1, AIX, Solaris. 
It fails on dUNIX 4.0b, HPUX.

Any ideas?  Here's the script:

----------------------------------------------------------------------
#!/bin/csh 
#
setenv FTT_DIR /usr/products/ftt/v1_5
setenv UPS_PROD_NAME FTT
eval set PROD_DIR=3D\$`echo $UPS_PROD_NAME | tr '[a-z]' '[A-Z]'`_DIR
echo $PROD_DIR
----------------------------------------------------------------------

Regards,

John

It was interesting to note that tcsh (as opposed to csh) got what
appeared to be "the right answer".  That is, the final echo parroted
back `date`.

You could still get this to work in csh if it's bothering you:

set line='`date`'
echo "$line"
`date`


	-- Farrell

[Posted by WWW Notes gateway]

>You could still get this to work in csh if it's bothering you:

I just came across it chasing down a bug in a script I was writing.
I got around it by using sh.

		tm

Instead of this:

eval set PROD_DIR=\$`echo $UPS_PROD_NAME | tr '[a-z]' '[A-Z]'`_DIR

do this:

eval set PROD_DIR = \$`echo $UPS_PROD_NAME | tr '[a-z]' '[A-Z]'`_DIR


There's probably a subtle difference in how various versions of the shell
tokenize things.  I've seen at least one other instance of this sort of
thing in an old C compiler that supported the (long since) deprecated =op
operators.  That feature of the complier gave vastly different meanings
to these two statements:

	foo=*bar;	/* foo = foo * bar; */
	foo = *bar;

It's sort of like the old jokes about JCL: neatness and precision on the
part of the programmer are encouraged.



	-- Farrell

[Posted by WWW Notes gateway]

Thanks Farrell.

The line in my original example was a bit different, it had characters in front of
it...

  eval set PROD_DIR = 3D\$`echo $UPS_PROD_NAME | tr '[a-z]' '[A-Z]'`_DIR
                      ^^

This gives me the same unexpanded output.  If I do this:


  setenv FTT_DIR /usr/products/ftt/v1_5
  setenv UPS_PROD_NAME \$FTT
                       ^^(added)
 
  eval set PROD_DIR = 3D`echo $UPS_PROD_NAME | tr '[a-z]' '[A-Z]'`_DIR
                      ^^ (\$ removed)
  echo $PROD_DIR


I get the right stuff.

Any idea why the behavior changed from 3.2?  Should we ponder it deeply?  ;)

I'll see if I can get my customer to accept this and be happy.  HP behaves this way,
so it isn't just unix 4.0.

Regards,

JD

I don't work on the shell so I can't speculate on why that change occurred.
Perhaps someone else might have a bit of insight into that.


	-- Farrell

[Posted by WWW Notes gateway]