Improving Ansi-term

I use ansi-term quite a bit. Why leave Emacs to have a terminal? However, there were a few issues I had with ansi-term that were quite annoying.

However, because Emacs is awesome, the issues were pretty easily fixed. First things first, I didn’t like that running exit in my terminal left a useless buffer around. A little searching around online, and I found the following solution, using defadvice:

    (defadvice term-sentinel (around my-advice-term-sentinel (proc msg))
     (if (memq (process-status proc) '(signal exit))
     (let ((buffer (process-buffer proc)))
     ad-do-it
     (kill-buffer buffer))
     ad-do-it))
    (ad-activate 'term-sentinel)

This tells term (which is used by ansi-term) to kill the buffer after the terminal is exited. The original I found online also killed the frame, but I use one frame with multiple windows, so I removed that call.

Secondly, I always use bash. I don’t need ansi-term to ask me which shell to use every time I invoke it. Once again, defadvice to the rescue. I wrote the following bit of advice that lets the user set the shell program to a variable, then advise ansi-term to always use that (and not ask). The defvar could just as easily be made a defcustom, and perhaps one day I’ll do that. For now, though, this works for me.

    (defvar my-term-shell "/bin/bash")
    (defadvice ansi-term (before force-bash)
     (interactive (list my-term-shell)))
    (ad-activate 'ansi-term)

Another issue I has was with the display of certain characters and control codes. The following hook sets the term to use UTF-8.

    (defun my-term-use-utf8 ()
     (set-buffer-process-coding-system 'utf-8-unix 'utf-8-unix))
    (add-hook 'term-exec-hook 'my-term-use-utf8)

Next, I wanted urls that show up in my terminal (via man pages, help, info, errors, etc) to be clickable. This was solved very easily by hooking goto-address-mode into ansi-term. To make add more hooks into ansi-term easier in the future, I defined my own hook function, currently with just goto-address-mode:

    (defun my-term-hook ()
     (goto-address-mode))

Then added my hook to term-mode-hook:

    (add-hook 'term-mode-hook 'my-term-hook)

After this, I realized that C-y doesn’t work in ansi-term like you’d expect. It pastes into the buffer, sure, but the text doesn’t get sent to the process. So if you copy a bash command, then C-y it into the buffer, nothing happens when you press enter (because, as far as ansi-term is concerned, no text was entered at the prompt). The following function will paste whatever is copied into ansi-term in such a way that the process can, well, process it:

    (defun my-term-paste (&optional string)
     (interactive)
     (process-send-string
     (get-buffer-process (current-buffer))
     (if string string (current-kill 0))))

Then I just add the binding to my hook from before, making it this:

    (defun my-term-hook ()
     (goto-address-mode)
     (define-key term-raw-map "\C-y" 'my-term-paste))

Since I’ve already hooked it into ‘term-mode-hook, there’s no reason to do so again. Simply reevaluate the function.

Finally, I’ve recently been using the solarized theme, both in Emacs and in my terminals. However, ansi-term wasn’t quite playing well with this. The colors were wrong in ansi-term, even though they were right in the rest of Emacs. A friend and co-worker of mine wrote the following bit of elisp that, when added to the term-mode-hook, makes ansi-term use the right colors for solarized. *(Note that this is only needed if you use solarized and your ansi-term doesn’t look right. Installing solarized, either in emacs or on your system, is beyond the scope of this post. However, I should mention that you can find it via M-x package-list-packages. The one you probably want is color-theme-solarized.) So, adding the elisp he wrote to my my-term-hook results in this:

    (defun my-term-hook ()
     (goto-address-mode)
     (define-key term-raw-map "\C-y" 'my-term-paste)
     (let ((base03 "#002b36")
     (base02 "#073642")
     (base01 "#586e75")
     (base00 "#657b83")
     (base0 "#839496")
     (base1 "#93a1a1")
     (base2 "#eee8d5")
     (base3 "#fdf6e3")
     (yellow "#b58900")
     (orange "#cb4b16")
     (red "#dc322f")
     (magenta "#d33682")
     (violet "#6c71c4")
     (blue "#268bd2")
     (cyan "#2aa198")
     (green "#859900"))
     (setq ansi-term-color-vector
     (vconcat `(unspecified ,base02 ,red ,green ,yellow ,blue
     ,magenta ,cyan ,base2)))))

Again, its already added to my term-mode-hook, so reevaluate and off we go.

So there you have it. With a little bit of elisp, ansi-term is much more streamlined (in my opinion) and better to work with. Hopefully this information will help others in the future.