Where is the find alias in eshell?

Question

I'm a newbie to eshell and I want to find the list function(s) which "find ./" calls. For the ls command I can use

which ls

which conveniently tells me where eshell/ls is, and links to the underlying function. On the other hand

which find

returns

find is an alias for `cl-find` in `cl.el`

but as far as I can see, there is no cl-find in cl.el, and clicking the link only takes me to the top of the cl.el file. How can I find the code which is evaluated by the find command? Is there any kind of convenient, general way of seeing the functions which get called by an eshell command?

Answer 1

cl-seq.el contains cl-find. The cl.el library contains a dolist with a bunch of names and a defalias for the list -- one of the entries is find: (dolist (fun '(. . . find-if-not find-if find nsubstitute-if-not . . .)) (let ((new (if (consp fun) (prog1 (cdr fun) (setq fun (car fun))) (intern (format "cl-%s" fun))))) (defalias fun new)))

Here are two examples to illustrate whether the eshell library is working behind the scenes running elisp code when a user types either find or which at the command prompt in an *eshell* buffer. To experiment with these examples it is necessary to first ensure the eshell and cl libraries are loaded:

(progn
  (require 'eshell)
  (require 'cl))

The first example tests the find command and the code being evaluated will return nil because there is no built-in elisp function that is specially called by default when a user types find in an *eshell* buffer at the command prompt:

(eshell-invoke-directly
  '(eshell-commands
    (progn
      (run-hooks (quote eshell-pre-command-hook))
      (catch
        (quote top-level)
          (progn
            (eshell-trap-errors
              (eshell-named-command "find"))))
      (run-hooks (quote eshell-post-command-hook)))))

The second example tests the which command and the code being evaluated will return t because there is a built-in elisp function that is specially called by default when a user types which in an *eshell* buffer at the command prompt:

(eshell-invoke-directly
  '(eshell-commands
    (progn
      (run-hooks (quote eshell-pre-command-hook))
      (catch
        (quote top-level)
          (progn
            (eshell-trap-errors
              (eshell-named-command "which"))))
      (run-hooks (quote eshell-post-command-hook)))))

The following is a list of some built-in elisp functions that are called when a user types just the suffix (i.e., the word after the forward-slash of the name of the function) at the command prompt in an *eshell* buffer -- this list was obtained using describe-function and the tab completion buffer:

eshell/.
eshell/addpath
eshell/agrep
eshell/alias
eshell/basename
eshell/cat
eshell/cd
eshell/clear
eshell/clear-scrollback
eshell/cp
eshell/date
eshell/define
eshell/diff
eshell/dirname
eshell/dirs
eshell/du
eshell/echo
eshell/egrep
eshell/env
eshell/eshell-debug
eshell/exit
eshell/export
eshell/fgrep
eshell/glimpse
eshell/grep
eshell/history
eshell/info
eshell/jobs
eshell/kill
eshell/listify
eshell/ln
eshell/locate
eshell/ls
eshell/make
eshell/man
eshell/mkdir
eshell/mv
eshell/occur
eshell/popd
eshell/printnl
eshell/pushd
eshell/pwd
eshell/rm
eshell/rmdir
eshell/setq
eshell/source
eshell/time
eshell/umask
eshell/unset
eshell/wait
eshell/which
eshell/whoami

---

See also the variable eshell-complex-commands, whose default value is '("ls") -- the doc-string for said variable is as follows:

  "A list of commands names or functions, that determine complexity.
That is, if a command is defined by a function named eshell/NAME,
and NAME is part of this list, it is invoked as a complex command.
Complex commands are always correct, but run much slower.  If a
command works fine without being part of this list, then it doesn't
need to be.

If an entry is a function, it will be called with the name, and should
return non-nil if the command is complex."