Thread: eval command

Hi guys,

I understand that eval will evaluate an expression and try to execute the returning command.
like

Code:

x=ls
eval $x
#will display files/dir

but if i use the following code

Code:

x=ls
$x
#will display files/dir

still ls will get executed. so where lies the advantage of using eval? What are other situtations eval can be used in?

Thanks a lot for your replies in advance.

I'm finding it hard to put into words, but consider this example:

Code:

VAR1=ls
VAR2=VAR1
eval \$$VAR2

In other words, VAR2 contains the name of another variable and I want to extract the value from the variable it references. It's almost like VAR2 is a pointer which points to VAR1, and the "eval" command is how you dereference it.

Try to accomplish what that example does without using eval. I think you'll find that you can't do it. That's why eval exists.