K 10
svn:author
V 6
jilles
K 8
svn:date
V 27
2016-01-23T23:00:38.736932Z
K 7
svn:log
V 242
sh: Use OLDPWD shell variable for 'cd -'.

Per POSIX, 'cd -' should use the OLDPWD shell variable, not internal state.
This variable is normally exported.

Also, if OLDPWD is not set, fail 'cd -' instead of changing to the current
directory.

END