27 Dec 2011 @ 8:03 PM 

So today, we’ll see how to pass a variable (and not the content of a variable) to a function.

The Problem

You need to create a function that updates one or multiple variables given as parameter. For example, let’s say you want to create a “to_upper” function, that will take a variable as parameter, then modify it.

If you do it like this :

to_upper $mytext

You will just receive the content of the variable. Then, what do you want to do with it ? Print it ? You can not return it to the variable, as you do not know it.

The solution :

Write your code like this :

function to_upper  {
eval _text=\$$1
export $1=`echo “${_text}” | tr [a-z] [A-Z]`
}

and you can execute it like this :

toto=”hello”

to_upper toto

echo $toto

HELLO

From there, you can execute everything, like SQL queries, and return them in the calling variable or in another variable… Of course, you still need to protect your function, checking that the given parameter is a name of a variable, and not the variable itself.

Thank you for reading !

Posted By: Dimi
Last Edit: 05 Jan 2012 @ 07:52 PM

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