topic Re: Using variable to execute command... in Operating System - HP-UX

Using variable to execute command...

Sébastien N — Thu, 17 Oct 2002 14:30:33 GMT

Hi,

I want to do something like that :
CMD="cat /etc/inittab > /tmp/inittab"
$CMD

The pb is that the ">" is not correctly parsed ! :-(
The $CMD is send to a function executing it and testing its return code.

Does anybody know the answer ?

Re: Using variable to execute command...

Christopher McCray_1 — Thu, 17 Oct 2002 14:32:33 GMT

Hello,

Try escaping it with
CMD="cat /etc/inittab \> /tmp/inittab"
$CMD

Hope this helps

Chris

Re: Using variable to execute command...

A. Clay Stephenson — Thu, 17 Oct 2002 14:36:42 GMT

CMD="cat /etc/inittab > /tmp/inittab"

eval "${CMD}"

That should fix you.

Re: Using variable to execute command...

S.K. Chan — Thu, 17 Oct 2002 14:39:00 GMT

This should work .. use $() as command substitution.

CMD=$(cat /etc/inittab > /tmp/inittab)
$CMD

Re: Using variable to execute command...

Sean OB_1 — Thu, 17 Oct 2002 15:28:06 GMT

Does it need to be as a variable?

Why not create them as functions.

cat_inittab ()
{
cat /etc/inittab > /tmp/inittab
}

then simply call the function.

# call function.
cat_inittab

Re: Using variable to execute command...

Sridhar Bhaskarla — Thu, 17 Oct 2002 19:20:56 GMT

Hi Sebastian,

A "3" will show your respect towards others for their time if they couldn't solve your problem. All the answers you got so far are "something" like what you said.

What you are executing is a command and it is to be treated with the same respect. So, you will need to do any of the following.

1. Declare it as a function and call the function.
2. Do exactly what you want to do but execute the variable with "eval" call.
3. Put it in command substitution syntax so that the shell will understand that it is a command.
4. Make it as an alias and run the alias.

alias CMD="cat /etc/inittab > /tmp/iniitab"
CMD

The solution closest to what you need is command substitution. If you don't want to use $ substitution, I guess you can replace double quotes with backticks (the key associated with ~).

CMD=`cat /etc/inittab > /tmp/inittab`
$CMD

-Sri

Re: Using variable to execute command...

Sébastien N — Fri, 18 Oct 2002 06:51:45 GMT

Hi everybody,

It was not a lack of respect, sorry if it has been missunderstood.

I also want to apologize A. Clay Stephenson because his solution works properly (I did a mistake when writing the command).

Thanx for all.

Sebastien.