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Assigning Variables

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# 1  
Old 03-04-2014
Assigning Variables
Hi,

Can the below be clarified please. i just want to know what is the difference between the two ways of assigning variables as mentioned below.

Code:
 
export SRC_TBL=${SRC_TBL-"MMA_COPAY_PLN_FACT_STG"}
export SRC_TBL="MMA_COPAY_PLN_FACT_STG"

thanks in advance Smilie

Arun
# 2  
Old 03-04-2014
The first means:
Quote:
${parameter-[word]}
Use Default Values. If parameter is unset, the expansion of word is substituted. Otherwise, the value of parameter is substituted.
The second is a regular variable assignment. The quotes are not necessary:

Both variables are exported.

To give an example:
Code:
$ echo "$var"

$ var=${var-foo}
$ echo "$var"
foo
$ var=
$ var=${var-foo}
$ echo "$var"

$ unset var
$ echo "$var"

$ var=${var-foo}
$ echo "$var"
foo

Last edited by Scrutinizer; 03-04-2014 at 04:00 AM..
This User Gave Thanks to Scrutinizer For This Post:
Arun Mishra
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