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From: "Brian Wilson" <wilson AT ds DOT net>
To: David T-G <d12 AT justpickone DOT org>, "CygWin Users' List" <cygwin AT cygwin DOT com>
Subject: Re: Command line arguments
Date: Thu, 1 Nov 2012 12:54:43 -0500
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> > % >${1}, ${2}, etc.  Also, you may want to read up on the getopts 
> > command as a % >way to process command line arguments. % Technically,
> > the {}'s are not needed. You can access them with $1, $2, ... % 
> > "/path/to/$1.save/dir" but not "/path/to/$1save/dir" you'd need the 
> > {} % (i.e. "/path/to/${1}save/dir" because otherwise the shell would 
> > be % looking for "1save" as an env variable name.
> 
> ... except that environment variables cannot begin with numbers :-)
>

True, but that won't keep the system from trying to interpret the string as 
a variable and erroring out on something a novice might easily write.

I got in the habbit of always using the "{}" (even if they aren't absolutely 
necessary) to avoid such issues on general principal.  It can also help keep 
things straight if you want to do something like the following line in a 
script 'VAR="${VAR}${VAR:+, }${VAR2}"' in a loop to create a comma-space 
separated string.  The first time through the loop, VAR is NULL and won't 
add anything to the string so only VAR2's value is assigned to VAR.  The 
next time through VAR is defined and will have "${VAR}, ${VAR2}" assigned 
back to VAR.  It's faster and cleaner than using an IF statement to do the 
same task.

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