Re: bash leaves all for loop constructs when assignment w. expression fails

[Chet Ramey]

as@schrell.de wrote:
> Configuration Information [Automatically generated, do not change]:
> Machine: i486
> OS: linux-gnu
> Compiler: gcc
> Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='i486' 
> -DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='i486-pc-linux-gnu' 
> -DCONF_VENDOR='pc' -DLOCALEDIR='/usr/share/locale' -DPACKAGE='bash' -DSHELL 
> -DHAVE_CONFIG_H   -I.  -I../bash -I../bash/include -I../bash/lib   -g -O2
> uname output: Linux lion 2.6.18-5-686 #1 SMP Mon Dec 24 16:41:07 UTC 2007 i686 
> GNU/Linux
> Machine Type: i486-pc-linux-gnu
>
> Bash Version: 3.1
> Patch Level: 17
> Release Status: release
>
> Description:
>     If you have an assignment with a wrong expression, e.g. VAR=$[8#9] bash
>     displays an error message and the script runs on. But if this error
>     is inside a for loop - or two nested for loops - bash leaves all loops
>     at once and goes to the next statement after all loops. I would expect
>     bash to continue with the next statement in the loop. Or at least abandon
>     the script. I do not have a problem with the error itself but with the
>     handling of it in the bash.

Your analysis is correct.  When bash encounters a variable assignment
error, it abandons execution of all "enclosing" commands, which includes
loops and shell functions, back to the top-level shell context.

At that point, bash decides whether or not to abandon execution entirely.
Shells running in Posix mode exit the shell script; shells not in Posix
mode do not.

Chet
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
                       Live Strong.  No day but today.
Chet Ramey, ITS, CWRU    chet@case.edu    http://cnswww.cns.cwru.edu/~chet/