Bash: Variable variables

[Nod]

Sometimes it is needed to make use of variable variables.
Lets say you want to build up a variable name by using another variable.
The first part of the variable is always the same (CMD in this case), but you have an incremental number behind it.

If we have:

# CMD1=one
# CMD2=two
# CMD3=three
# CMD4=four

You could print it by using:

for i in $CMD1 $CMD2 $CMD3 $CMD4
do
     echo $i
done

This would work if you only have a small number of variables.

If you have a few hundred, then this would work better:

# for i in `seq 1 4`
> do 
>      var="CMD${i}"
>      echo ${!var}
> done
one
two
three
four

 

[bullzeye.za]

This is pretty cool