Hi,
I discovered this strange behavior of eshell in emacs 23.1.1 (on MacOSX and Debian Lenny, both built from source, launched with '-q').
It seems that the presence of two slashes ("//") in a path breaks the search:
Example:
~ $ export PATH=/usr//bin
~ $ which m4
which: no m4 in (/usr//bin)
~ $ export PATH=/usr/bin
~ $ which m4
/usr/bin/m4
~ $
I mailed this to
johnw@gnu.org (maintainer of eshell) who told me that it seems to be an Emacs issue.
Cheers,
Sebastien Mondet
http://seb.mondet.org