Date: Fri, 9 Jul 1999 08:55:59 -0700 (PDT) From: pfeifer@dbai.tuwien.ac.at To: freebsd-gnats-submit@freebsd.org Subject: bin/12578: `cd somewhere` changes current working directory in /bin/sh scripts Message-ID: <19990709155559.8B96B14EA4@hub.freebsd.org>
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>Number: 12578
>Category: bin
>Synopsis: `cd somewhere` changes current working directory in /bin/sh scripts
>Confidential: no
>Severity: critical
>Priority: high
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Fri Jul 9 09:00:01 PDT 1999
>Closed-Date:
>Last-Modified:
>Originator: Gerald Pfeifer
>Release: FreeBSD 3.2-RELEASE i386
>Organization:
>Environment:
FreeBSD polaris.dbai.tuwien.ac.at 3.2-RELEASE FreeBSD 3.2-RELEASE #0:
Tue May 18 04:05:08 GMT 1999 jkh@cathair:/usr/src/sys/compile/GENERIC i386
>Description:
`man sh` says
Command Substitution
Command substitution allows the output of a command to be substituted in
place of the command name itself. Command substitution occurs when the
command is enclosed as follows:
$(command)
or (``backquoted'' version):
`command`
The shell expands the command substitution by executing command in a sub-
shell environment and replacing the command substitution with the stan-
dard output of the command,
yet a `cd /some/where` actually does change the current working
directory of a shell script it occurs in, i.e., apparently it is
not invoked in a sub-shell.
Debian GNU/Linux 2.1 (with bash), Solaris 2.6, AIX 4.1 and DEC OSF1 4.0
behave as expected, see "How to repeat the problem".
>How-To-Repeat:
Run the following script:
#!/bin/sh
cd /tmp
echo .`cd /`.
pwd
The expected output (as obtained on Solaris 2.6, Debian GNU/Linux 2.1,
AIX 4.1 and DEC OSF1 4.0) is as follows
..
/tmp
while FreeBSD 3.2 incorrectly prints
..
/
>Fix:
Replace /bin/sh by bash.
>Release-Note:
>Audit-Trail:
>Unformatted:
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