Why parse lines with colons

[Nick Landsberg]

One of the reasons /bin/sh (bsh to those who like csh)
parses lines with ":" in the beginning is because of
constructs like the following:

: ${FOO:-default}

This effectively sets $FOO to a default value if not previously
set.  The longhand way would be:

if [ "${FOO}" = "" ]
then
	FOO=default
fi


		From the hairy eyeball of ---
		Nick Landsberg ( ....!spuxll!npl)