Andreas Schwab wrote:
Linda Walsh <b...@tlinx.org> writes:
if [[ -z "" && ((LINES < 80 )) ]]; then echo foo; fi
(prints nothing)....
What am I missing?
"LINES" does not sort before "80".
Andreas.
But it compares == to 66?
Normally, in the shell, if you type in something in double parens
it does a mathematical evaluation.
i.e.
if you are in a while loop
lines=0
while read foobar; {
((++lines)) #increments value of lines by 1
((lines>23)) && break; #and quits if more than 23 lines are read
}
so I'd expect the above to eval my shell-var, 'lines'...
Ah....I see....I need another set of parens!...
(ARG....!!....
What rule should I have remembered to 'know' that?
'if in [[ ]], then you need an extra level of parens around a double-paren
expression to get mathematical evaluation'...
(seems like a pretty specific rule (i.e. does it generalize from something?))
I guess many of us are still learning about these things as they unfold --
and of course Chet keeps ahead of us by continually throwing in more benefits...
(if we can decipher them!)...
-l
