Re: Fix for Arg list too long

[Alexandre Oliva]

On Feb  1, 2001, "Boehne, Robert" <address@hidden> wrote:

> If 'expr' is used to check if the arguments list is too long, do we
> have to worry about 'expr' being a shell built-in?
 
Hmm...  Presumably, yes, however I've never heard of expr as a
built-in.  I'd use the $0 --fallback-echo approach.

> testring="ABCDEFGHIJKLMNOPQR"
> i=0
> result=0
> while test $? -eq 0

Testing $? here is not portable.  Assignments don't always change $?.

How about:

  while test `$0 --fallback-echo "X$testring"` = "X$testring" &&
        new_result=`expr "X$testring" : ".*"` &&
        result=$new_result &&
        test $i != 16 # 1 MB should be enough
  do
        i=`expr $i + 1`
        testring=$testring$testring
  done

There's one thing I'm a little bit worried about, though.  There's a
possibility that expr may not support long strings, when wc or awk
would.

I know some exprs won't print matches wider than 128 bytes, but I
don't know of any limitation when only the length of the match is
requested, as in our case.

This would result in our using command lines shorter than available.
No big deal, I suppose.  And users will probably ask about it, so we
can fix it!

-- 
Alexandre Oliva   Enjoy Guarana', see http://www.ic.unicamp.br/~oliva/
Red Hat GCC Developer                  address@hidden, redhat.com}
CS PhD student at IC-Unicamp        address@hidden, gnu.org}
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