while loops + while :

blizunt7 · 12-04-2004, 04:22 PM

hey all,

i recently saw in a script:

while :
do

commands.....

done

what does.. while :
mean???? thanks so much
josh

michaelk · 12-04-2004, 05:19 PM

It is known as a loop. Basically its for repeating commands until the while condition is meet.
http://www.faqs.org/docs/abs/HTML/loops.html
http://tille.soti.org/training/bash/ch09s02.html

blizunt7 · 12-04-2004, 05:25 PM

haha, sorry i should have specified. I am well aware of what a loop is.

the colon after the while statement, is what i am interested in.
I saw this in a script. just curious what it menas.
thanks again

zhangmaike · 12-04-2004, 05:27 PM

The : is a null command. The while loop loops until the command after the "while" keyword returns a non-zero exit code. : always returns 0, so this is an infinite loop.