[u-u] Sams book

[Jim Mercer]

On Fri, Jan 15, 2016 at 03:25:57PM -0500, D. Hugh Redelmeier wrote:
> | From: Jim Mercer <jim at reptiles.org>
> 
> | -e completely changes the way the shell runs, and i highly suggest never
> | enabling it.
> | 
> | for example, if you have anything like
> | 
> | #! /bin/sh
> | 
> | someprog -a -b -c
> | if [ $? -ne 0 ] ; then
> |    take some action
> | fi
> 
> More clearly written as:
> 	someprog -a -b -c || take some action
> or
> 	if ! someprog -a -b -c ; then
> 		take some action
> 	fi

for some other definition of 'clearly' than i'm used to.

:-)

> And these are faster on the original Bourne shell (where [ was not a builtin).

if speed is a factor, bourne shell might not be the appropriate tool.

> | it totally will not do what you think.
> 
> I agree that it is a change in how one thinks.  A good one.

and you problably like perl too.

:-)

> | i lost a chunk of hair trying to figure out why a script were failing
> | silently, then discovered that someone had put in "#! /bin/bash -e"
> 
> I like to be able to say "bash -x scriptname" so putting the flag in
> the shebang is not appropriate.

yep, but, apparently adding args to shebang is getting to be all the rage these days.

-- 
Jim Mercer     Reptilian Research      jim at reptiles.org    +1 416 410-5633

Life should not be a journey to the grave with the intention of
arriving safely in a pretty and well preserved body, but rather
to skid in broadside in a cloud of smoke, thoroughly used up,
totally worn out, and loudly proclaiming "Wow! What a Ride!"
 -- Hunter S. Thompson