--- a/doc/hgrc.5.txt
+++ b/doc/hgrc.5.txt
@@ -15,26 +15,38 @@ aspects of its behaviour.
 FILES
 -----
 
-Mercurial reads configuration data from up to three files, if they
-exist.  The names of these files depend on the system on which
-Mercurial is installed.
+Mercurial reads configuration data from several files, if they exist.
+The names of these files depend on the system on which Mercurial is
+installed.
 
+(Unix)    <install-root>/etc/mercurial/hgrc.d/*.rc::
+(Unix)    <install-root>/etc/mercurial/hgrc::
+    Per-installation configuration files, searched for in the
+    directory where Mercurial is installed.  For example, if installed
+    in /shared/tools, Mercurial will look in
+    /shared/tools/etc/mercurial/hgrc.  Options in these files apply to
+    all Mercurial commands executed by any user in any directory.
+
+(Unix)    /etc/mercurial/hgrc.d/*.rc::
 (Unix)    /etc/mercurial/hgrc::
 (Windows) C:\Mercurial\Mercurial.ini::
-    Options in this global configuration file apply to all Mercurial
-    commands executed by any user in any directory.
+    Per-system configuration files, for the system on which Mercurial
+    is running.  Options in these files apply to all Mercurial
+    commands executed by any user in any directory.  Options in these
+    files override per-installation options.
 
 (Unix)    $HOME/.hgrc::
 (Windows) C:\Documents and Settings\USERNAME\Mercurial.ini
-    Per-user configuration options that apply to all Mercurial commands,
-    no matter from which directory they are run.  Values in this file
-    override global settings.
+    Per-user configuration file, for the user running Mercurial.
+    Options in this file apply to all Mercurial commands executed by
+    any user in any directory.  Options in this file override
+    per-installation and per-system options.
 
 (Unix, Windows) <repo>/.hg/hgrc::
     Per-repository configuration options that only apply in a
     particular repository.  This file is not version-controlled, and
-    will not get transferred during a "clone" operation.  Values in
-    this file override global and per-user settings.
+    will not get transferred during a "clone" operation.  Options in
+    this file override options in all other configuration files.
 
 SYNTAX
 ------

--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -42,16 +42,16 @@ def matchpats(repo, pats=[], opts={}, he
     return util.cmdmatcher(repo.root, cwd, pats or ['.'], opts.get('include'),
                         opts.get('exclude'), head) + (cwd,)
 
-def makewalk(repo, pats, opts, head=''):
+def makewalk(repo, pats, opts, node=None, head=''):
     files, matchfn, anypats, cwd = matchpats(repo, pats, opts, head)
     exact = dict(zip(files, files))
     def walk():
-        for src, fn in repo.walk(files=files, match=matchfn):
+        for src, fn in repo.walk(node=node, files=files, match=matchfn):
             yield src, fn, util.pathto(cwd, fn), fn in exact
     return files, matchfn, walk()
 
-def walk(repo, pats, opts, head=''):
-    files, matchfn, results = makewalk(repo, pats, opts, head)
+def walk(repo, pats, opts, node=None, head=''):
+    files, matchfn, results = makewalk(repo, pats, opts, node, head)
     for r in results:
         yield r
 
@@ -635,20 +635,14 @@ def cat(ui, repo, file1, *pats, **opts):
     mf = {}
     rev = opts['rev']
     if rev:
-        change = repo.changelog.read(repo.lookup(rev))
-        mf = repo.manifest.read(change[0])
-    for src, abs, rel, exact in walk(repo, (file1,) + pats, opts):
+        node = repo.lookup(rev)
+    else:
+        node = repo.changelog.tip()
+    change = repo.changelog.read(node)
+    mf = repo.manifest.read(change[0])
+    for src, abs, rel, exact in walk(repo, (file1,) + pats, opts, node):
         r = repo.file(abs)
-        if rev:
-            try:
-                n = mf[abs]
-            except (hg.RepoError, KeyError):
-                try:
-                    n = r.lookup(rev)
-                except KeyError, inst:
-                    raise util.Abort(_('cannot find file %s in rev %s'), rel, rev)
-        else:
-            n = r.tip()
+        n = mf[abs]
         fp = make_file(repo, r, opts['output'], node=n, pathname=abs)
         fp.write(r.read(n))
 

--- a/mercurial/localrepo.py
+++ b/mercurial/localrepo.py
@@ -462,8 +462,14 @@ class localrepository(object):
 
     def walk(self, node=None, files=[], match=util.always):
         if node:
+            fdict = dict.fromkeys(files)
             for fn in self.manifest.read(self.changelog.read(node)[0]):
-                if match(fn): yield 'm', fn
+                fdict.pop(fn, None)
+                if match(fn):
+                    yield 'm', fn
+            for fn in fdict:
+                self.ui.warn(_('%s: No such file in rev %s\n') % (
+                    util.pathto(self.getcwd(), fn), short(node)))
         else:
             for src, fn in self.dirstate.walk(files, match):
                 yield src, fn

--- a/mercurial/util.py
+++ b/mercurial/util.py
@@ -13,7 +13,7 @@ platform-specific details from the core.
 import os, errno
 from i18n import gettext as _
 from demandload import *
-demandload(globals(), "re cStringIO shutil popen2 tempfile threading time")
+demandload(globals(), "re cStringIO shutil popen2 sys tempfile threading time")
 
 def pipefilter(s, cmd):
     '''filter string S through command CMD, returning its output'''
@@ -510,12 +510,18 @@ if os.name == 'nt':
 else:
     nulldev = '/dev/null'
 
-    hgrcd = '/etc/mercurial/hgrc.d'
-    hgrcs = []
-    if os.path.isdir(hgrcd):
-        hgrcs = [f for f in os.listdir(hgrcd) if f.endswith(".rc")]
-    rcpath = map(os.path.normpath, hgrcs +
-                 ['/etc/mercurial/hgrc', os.path.expanduser('~/.hgrc')])
+    def rcfiles(path):
+        rcs = [os.path.join(path, 'hgrc')]
+        rcdir = os.path.join(path, 'hgrc.d')
+        try:
+            rcs.extend([os.path.join(rcdir, f) for f in os.listdir(rcdir)
+                        if f.endswith(".rc")])
+        except OSError, inst: pass
+        return rcs
+    rcpath = rcfiles(os.path.dirname(sys.argv[0]) + '/../etc/mercurial')
+    rcpath.extend(rcfiles('/etc/mercurial'))
+    rcpath.append(os.path.expanduser('~/.hgrc'))
+    rcpath = [os.path.normpath(f) for f in rcpath]
 
     def parse_patch_output(output_line):
         """parses the output produced by patch and returns the file name"""

new file mode 100755
--- /dev/null
+++ b/tests/test-cat
@@ -0,0 +1,18 @@
+#!/bin/sh
+#
+mkdir t
+cd t
+hg init
+echo 0 > a
+echo 0 > b
+hg ci -A -m m -d "0 0"
+hg rm a
+hg cat a
+sleep 1 # make sure mtime is changed
+echo 1 > b
+hg ci -m m -d "0 0"
+echo 2 > b
+hg cat -r 0 a
+hg cat -r 0 b
+hg cat -r 1 a
+hg cat -r 1 b

new file mode 100644
--- /dev/null
+++ b/tests/test-cat.out
@@ -0,0 +1,7 @@
+adding a
+adding b
+0
+0
+0
+a: No such file in rev 551e7cb14b32
+1