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Date: Wed, 9 Apr 1997 22:03:33 -0700 (PDT)
From: filo@yahoo.com
To: freebsd-gnats-submit@freebsd.org
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Subject: bin/3245: variable substitution "a=${a:=}" in /bin/sh causes infinite loop
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>Number:         3245
>Category:       bin
>Synopsis:       variable substitution "a=${a:=}" in /bin/sh causes infinite loop
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Wed Apr  9 22:10:01 PDT 1997
>Last-Modified:
>Originator:     david filo
>Organization:
yahoo
>Release:        2.2-stable (as of 4/9/97)
>Environment:
FreeBSD 67.yahoo.com 2.2-STABLE FreeBSD 2.2-STABLE #0: Thu Apr 10 01:06:58 GMT 1997
>Description:
the following variable substitution in /bin/sh results in an
infinite loop, provided a has a null value.  by definition it should
set a to null.

a=${a:=}
>How-To-Repeat:
run the following script

#!/bin/sh
a=
a=${a:=}
>Fix:

>Audit-Trail:
>Unformatted: