GNU Emacs / XEmacs tip #(incf emacsen-tip-number)

[karlheg@hegbloom.net (Karl M. Hegbloom)]

 I just did an "apt-get source" in the course of gathering mise en
 place to study OpenLDAP, and needed a quick way to review the man
 pages for all of the Build-Depends libraries, etc.  Here's my
 five minute solution.

 First, I visited "debian/control", and used "C-space C-e M-w"[1] to
 grab a copy of the Build-Depends line.  Here's what it looks like:

Build-Depends: libdb3-dev, libwrap0-dev, debhelper (>= 2.0.54), libiodbc2-dev, patch, libsasl-dev, dpkg-dev (>= 1.7.1), libncurses5-dev

 I then did "M-x shell", then "C-y" to grab that into a shell prompt,
 after a quick "cd" to a more convienient location than the "debian/"
 directory of OpenLDAP 2.  I editted it, removing the header, the
 commas, and the version numbers, leaving just a space separated list,
 and then stuck it in a shell variable for easy access.

 % export pkgs="libdb3-dev libwrap0-dev debhelper libiodbc2-dev patch libsasl-dev dpkg-dev libncurses5-dev"

 I made sure those packages were all installed with a quick[2]:

 % sudo apt-get -q install $pkgs

 ... and then:

 % for pkg in $pkgs; do egrep '/man/' /var/lib/dpkg/info/$pkg.list >> manlist.txt; done

 After that, I did "C-x C-f manlist.txt", and wrote the following lisp
 function, which is now in my `user-init-file'[3]:

(require 'thingatpt)
(defun man-locally-at-point ()
  (interactive)
  (let ((manpage (thing-at-point 'filename)))
    (if (= 1 (function-max-args #'manual-entry))
	(manual-entry (concat manpage " -l"))
      (manual-entry manpage "-l"))))

 With my cursor on an interesting line in that "manlist.txt" file now,
 I can type "M-x man-locally-at-point", and instantly have the man
 page in view.

 For browsing man pages that are part of a source package, here's what
 I do:

(defun dired-man-locally ()
  (interactive)
  (if (= 1 (function-max-args #'manual-entry))
      (manual-entry (concat (dired-get-filename) " -l"))
    (manual-entry (dired-get-filename) "-l")))

(add-hook 'dired-setup-keys-hook
	  #'(lambda ()
	      (define-key dired-mode-map [(?l)] #'dired-man-locally)))

 Now the "l" key in dired mode invokes `dired-man-locally'.


Footnotes: 
[1]  If you don't know what that did, here's a hint.  "F1-k" invokes
     `describe-key-binding', "F1-f" invokes `describe-function', and
     "F1-a" invokes `apropos'.

[2]  The "-q" here is for "quiet", not "quick".  It suppresses the
     spinners and updating percentage transfered, which doesn't work
     right in the emacs shell mode.  I don't know why "apt-get"
     doesn't just check the term settings to see if it can do that.

[3]  This is compatible with both GNU Emacs and XEmacs.