farnham@bu-tyng.bu.edu (Dave Farnham) (02/22/90)
I am attempting to do the following in the Bourne shell.
1. Perform a 'read' on a variable in a function through
the position parameters.
2. Loop while the variable contains a NULL string (force
the user to input something).
The following code works, but I had to use a temporary variable.
I tried to use 'eval' in my test condition and I think the root
of my problems is a lack of understanding of what exactly 'eval'
does and how it works. I know there are probably a hundred ways
to re-write my function, rather than "use this it's better". I
would really appreciate a re-write with an explanation.
Thanks
Dave
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#!/bin/sh
fun() {
tmp=""
while [ -z "$tmp" ] # I tried to use eval here on "\$$1"
do
echo "Enter $2 " # Enter "text string"
read `echo $1` # Read into a variable
eval tmp="\$$1" # tmp=$variable
done
}
fun var1 name
fun var2 age
echo $var1
echo $var2
------------------
Dave Farnham
( ...!uunet!wang!bu-tyng!farnham , farnham@bu-tyng.bu.edu )
Tel: (508) 649-9731
Fax: (508) 649-6926