/bin/sh variable substitution

[Dave Sherman]

In article <4260 at mordor.UUCP> jdb at mordor.UUCP (John Bruner) writes:
~| I noticed recently that the (Bourne) shell's ${X=y} construction
~| does not have the behavior that I expected.  It appears that when
~| a variable is assigned a quoted value, for example:
~| 
~| 	${XYZZY="plugh"}  <or>	${XYZZY='plugh'}
~| 
~| that every character of the quoted value is stored with the 0200
~| bit on.  Normally this has no visible effect because the shell
~| strips the eighth bit (along with  non-printable characters) after
~| variable substitution when it evaluates a command.  However, this
~| is not the case for "<<" I/O redirection: the variables are passed
~| unfiltered. 
~| 

Aha! That explains the strange behaviour I got on one system, where
I was trying to use "cu" across a hardwired line, requiring a null
first argument (nothing to dial).

I can type to the shell:
	cu "" -s 2400 -l /dev/whatever

but when I put CU='cu "" -s 2400 -l /dev/whatever' in my .profile,
I couldn't get $CU to work, and the error meesage from cu was one
I couldn't reproduce by typing at the screen. No amount of fiddling
with different combinations of quoting chars helped. Musta been those
eighth bits acting up. Yep, it's a bug.

Dave Sherman
Toronto
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