Problem in executing a comand liying inside a variable

Nene · #1 (**permalink**) 08-09-2006

Hi everyone!

I need some help with my shell script

I am sending a shell command from a html text input to a cgi. Then, I store it into a variable. For example

var="ps -axu"
echo `$var`

This functions properly. But consider the following...

var="ps -axu | grep root"

Now, I want to execute this command but if I do this:

echo `$var`

it produces an error.

Why when I add pipes into my string it does not work?

Thank you a lot

tmarikle · #2 (**permalink**) 08-09-2006

If you really want to do it this way, you need to eval the command.

Code:

var="eval ps -axu | grep root"
echo `$var`

but really, what are you trying to accomplish?

Nene · #3 (**permalink**) 08-09-2006

It works!

I need to execute an arbitrary command introduced by the user in an html form and print the result. It's for a university subject.

Thank you!!!

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