difference between "QUIET=${QUIET:-yes}" and "QUIET=yes"

akash_mahakode · November 11, 2009, 1:14am

Hi,

Can anyone tell me the difference between

QUIET=${QUIET:-yes}

and 

QUIET=yes

.

Regards,
akash

Scrutinizer · November 11, 2009, 1:24am

From the man page:

${parameter:-word}
          If parameter is set and is non-null then substitute its value; otherwise substitute word.

kinny · November 11, 2009, 1:42am

If the QUIET variable is not set it will be default to yes in the first case

QUIET variable will be set to YES in the second case