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Re: Assignment errors with no additional words expanded in non-POSIX mod


From: Chet Ramey
Subject: Re: Assignment errors with no additional words expanded in non-POSIX mode fails to abort
Date: Sat, 12 Jan 2013 18:17:03 -0500
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On 1/11/13 1:17 PM, Dan Douglas wrote:
> Whether or not this type of error aborts depends upon there being an actual 
> newline.

It doesn't actually abort the script itself; the assignment error causes
the current command to be aborted.  Posix mode does cause script exit.

>     $ bash -c 'echo pre; foo=$((8#9)); echo post' 2>&1
>     pre
>     bash: 8#9: value too great for base (error token is "8#9")
> 
>     $ bash -c $'echo pre\nfoo=$((8#9))\necho post' 2>&1
>     pre
>     bash: line 1: 8#9: value too great for base (error token is "8#9")
>     post

This is one place where newlines and semicolons are not equivalent.  The
semicolons in the first command result in a single command (a list).  The
newlines in the second case result in three commands (remember that bash
always reads a line at a time).

When the expansion error in the assignment causes the current command to
abort, it has different effects based on whether that command is a list or
a simple command.

Chet
- -- 
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, ITS, CWRU    address@hidden    http://cnswww.cns.cwru.edu/~chet/
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