Re: getting weird output out of 'echo' w/args

2013-05-30 Thread Davide Brini
On Thu, 30 May 2013 08:53:48 +0300, Pierre Gaston pierre.gas...@gmail.com wrote: Missing quotes around [ ] can be nasty eg #!/bin/bash shopt -s nullglob # sounds a good idea! . . i=0 while read a[i++]; do echo ${a[i]} # why oh why nothing is printed! done hello It seems

Re: getting weird output out of 'echo' w/args

2013-05-30 Thread Chris Down
Pierre is referring to the fact that [i++] is evaluated as a glob by the shell, the reason it doesn't work is because $i is postincremented instead of preincremented. You can see what he means here: $ shopt -u nullglob $ i=0 $ while read a[++i]; do echo ${a[i]} done hello hello $ shopt -s

Re: getting weird output out of 'echo' w/args

2013-05-30 Thread Davide Brini
On Thu, 30 May 2013 16:56:36 +0800, Chris Down ch...@chrisdown.name wrote: Pierre is referring to the fact that [i++] is evaluated as a glob by the shell, the reason it doesn't work is because $i is postincremented instead of preincremented. You can see what he means here: $ shopt -u

Re: getting weird output out of 'echo' w/args

2013-05-30 Thread Chris Down
That's... why I said he was unintentionally doing postincrement... On 30 May 2013 17:04, Davide Brini dave...@gmx.com wrote: On Thu, 30 May 2013 16:56:36 +0800, Chris Down ch...@chrisdown.name wrote: Pierre is referring to the fact that [i++] is evaluated as a glob by the shell, the reason it

Re: getting weird output out of 'echo' w/args

2013-05-30 Thread Pierre Gaston
On Thu, May 30, 2013 at 12:04 PM, Davide Brini dave...@gmx.com wrote: On Thu, 30 May 2013 16:56:36 +0800, Chris Down ch...@chrisdown.name wrote: Pierre is referring to the fact that [i++] is evaluated as a glob by the shell, the reason it doesn't work is because $i is postincremented instead

Re: getting weird output out of 'echo' w/args

2013-05-30 Thread Davide Brini
On Thu, 30 May 2013 17:06:08 +0800, Chris Down ch...@chrisdown.name wrote: That's... why I said he was unintentionally doing postincrement... Doh! Indeed you said that. Apologies for reading too fast. -- D.

Re: getting weird output out of 'echo' w/args

2013-05-30 Thread Linda Walsh
Pierre Gaston wrote: ok sorry for not having try my example, my point is that it was not assigning to a[0] because of the nullglob and that this one can be hard to spot --- Generally don't feel good about that op except in very narrow circumstances...for exactly those types of

Re: getting weird output out of 'echo' w/args

2013-05-30 Thread Chris Down
On 30 May 2013 17:59, Linda Walsh b...@tlinx.org wrote: Generally don't feel good about that op except in very narrow circumstances...for exactly those types of reasons...what you can't see CAN hurt you! ;-) It doesn't have anything to do with the operator, it's to do with the usage of