Preserving values with for loop for later use

Shell Programming and Scripting
1

Below is the issue I am having.

I have a few variables which have certain values in them like
var1=23
var2=46
var3=78 etc...

I want to save these values with the help of a for loop in a single variable so that I can use it later,beacuse a few lines down the script, some of these variables get set to a different value and I would like to reset them to the values that I had saved.Can you point out a way without using arrays?

2

I would put the problem code in a subshell instead, to prevent its changes from affecting the rest of the shell.

#!/bin/sh

VAR1=asdf
VAR2=qwertyuipo

(
        VAR1=slartibartfast
        VAR2=lkjlkdsfh

        echo "some stuff"
)

echo "Variables changed inside ( ) do not change outside"
echo "VAR1 is still $VAR1"
3

Can I do something like this?

 
temp=`for t in var1 var2 var3; do <save the value> ; done`
<loop which sets the values to a different value>
eval echo $temp

Is there a way I can save the initial values of the variables in a single variable as above(temp)

4

That would be ugly, glitch-prone, and a gaping security hole(never use eval), which is why I suggested the alternative.

This could work, if your variables don't have more than one line in them.

printf "%s\n" "$var1" "$var2" "$var3" > save

for X in var1 var2 var3
do
        read $X
done < save

rm -f save

But again, the best way would be to avoid the problem completely by using a subshell -- that's one reason they exist. Or just don't overwrite those variables in the first place.