The single most useful Emacs feature

http://stackoverflow.com/questions/60367/the-single-most-useful-emacs-feature

by rodw • 15 years ago

216 110 15 years ago

nyellin5• 15 years ago

It isn't an official part of Emacs, but no Emacs user should go without installing el-get, the meta-package-manager for Emacs.

https://github.com/dimitri/el-get

El-get can install and update elisp from git, svn, http, and EmacsWiki. (It also wraps ELPA and apt-get where packages exist.)

If el-get doesn't have a recipe for your favorite Emacs extension, please consider adding the recipe and pushing to GitHub. (It doesn't take long - most recipes are only a few lines long.) Don't forget to issue a pull request for the rest of us.

justinhj2• 15 years ago

I use package.el Any advantage to swapping to el-get?

nyellin5• 15 years ago

Yes, package.el doesn't install arbitrary snippets from anywhere on the internet.

vdm• 15 years ago

+1. el-get is the homebrew of Emacs, and is even better for letting you hook in to do custom init.

dman• 15 years ago

slime - emacs package for editing, running, debugging and enjoying lisp.

pjscott• 15 years ago

It's the finest IDE I've seen for any language.

kakuri• 15 years ago

I can't switch away from Notepad++ to any editor that lacks instantaneous, no-hassle (no extra key presses), buttery smooth current buffer word auto-complete.

tptacek5• 15 years ago

Thank you for sharing.

jrockway7• 15 years ago

Presumably you have to press a key to accept a completion. With dabbrev or hippie-expand, you don't.

tptacek5• 15 years ago

hi-lock-mode!

Hi-lock lets you specify regexes to highlight anywhere in a file; it's like domain-specific font-lock.

It's astoundingly useful in code review. For instance, given a giant blob of J2EE web handler code, I can eyeball one handler, recognize the annotation mapping the method to URL syntax, and then punch in a hi-lock regex to light up similar annotations everywhere in the file, then glance through the whole file looking for color patterns. I can read any of those functions and recognize the code that checks "am I an admin", hi-lock it, and then quickly spot any function mapped to a URL that doesn't check admin credentials.

That's just one tiny use case. I used hi-lock so much I ported it into our web-based code review tool. I converted one person to Emacs just to get that feature (my office would be thrilled if someone could point out the vim package that does the same thing).

CUA column editing (CTR-SPC arrow-arrow-&c type-type-&c) is probably my #2.

Late edit:

Holy hell how do you forget magit! Magit is a near-complete UI for git; it figures out what git repo you're working from, and then gives you up-to-date status on the contents of your checkout, spots untracked files, allows you to visually stage your commits, gives you single-key revert and a browsable repo history.

Magit is one of the rare Emacs extensions that not only improves Emacs but also the external service it integrates with. I am actually a better git user (or, git is just better) when I've got magit running.

jrockway7• 15 years ago

Occur also works nicely for this use case, as you can visit each place in order with C-x `. Actually, something like eproject-grep is even nicer, because you can visit every occurrence in the project that way.

tptacek5• 15 years ago

I didn't know about occur, which is awesome and thanks. The benefit of hi-lock is that I can "read" code without actually having to "read" it.

Instead, I can either set myself up to look for patterns of colors (function --- red line --- shit no blue line!), or set myself to serendipitously discover things as I actually do read code.

I have never, ever, ever, ever figured out an Emacs "grep" that I liked enough to stop using find/xargs/grep from eshell.

burgerbrain• 15 years ago

I've been trying to figure out a good way to do this for a while in vim, and can't say I've found much. The best i can figure is something to this effect:

  highlight LowVis ctermbg=233 guibg=233 ctermfg=240
  syn region LowVis start="\s*log_" end=";" contains=LowVis oneline

gregsexton• 15 years ago

Have you tried `:help :match`? I'm not sure if I'm missing anything but this seems to do the same thing.

manlon• 15 years ago

This vim plugin seems to do most of what you describe by wrapping the matchadd() vimscript function:

http://www.vim.org/scripts/script.php?script_id=2666

<Leader>r (regex) to add matches to the set of highlighted groups.

ludwigvan3• 15 years ago

Out of curiosity, do you use usually emacs for J2EE code?

I am an emacs user, but have been doing some J2EE stuff for the last few months, and have been getting really annoyed by the IDE's lately, and I was wondering if it was a wise choice to go with emacs for Java too.

tptacek5• 15 years ago

I don't build J2EE apps; I just break them. We built our own code reviewing tool internally, which is what I use now, but I spent a few months reviewing things in Emacs deliberately once I learned about hi-lock mode.

I still do all my real dev in Emacs and have more than once put hi-lock to good use there.

I'd rather eat a bug than use Eclipse.

ww5202• 15 years ago

For Java work, I use Emacs and command line tools.

bostonvaulter2• 15 years ago

That actually sounds like a useful browser-wide extension (rather than just building it into a code-review tool).

jpdoctor• 15 years ago

Good god. I've been using emacs since 1981 and this thread is teaching me things.

mark_h2• 15 years ago

I've "only" been using it since 1998, but I always skim threads like this -- even lots of short articles -- because there's nearly always something new to discover! Sometimes it's hard not to gush, but it's just such an amazing and organic piece of software.

diminish• 15 years ago

i was escaping it since 1992, and now i jumped into it while reading this.. and i admire.

nessus42• 15 years ago

Likewise! How will I ever get any work done with all these new productivity features I'm learning about!

My favorite Emacs feature that I've learned about in the past year is Org-Mode. I use it now for just about everything.

rodw• 15 years ago

Org-mode is what finally converted me to being an emacs user.

I'd been searching for a lightweight, console/cli-mode outliner/task-manager when it occurred to me "surely emacs has something for this". It did, of course.

For several weeks I used emacs only for org-mode. Slowly but surely emacs started to take over my more and more of my editing tasks. Now I find myself not even bothering to launch X, but simply emacs from the Linux console (run level 3?). It's amazing how responsive a computer is when you're not using any gui at all.

I've since discovered that org-mode is pretty common gateway into emacs.

bbwharris• 15 years ago

Isn't it funny how the rabbit hole just keeps going?

tjr2• 15 years ago

It's nothing unique to Emacs, but I get a lot of use out of M-q.

nixme• 15 years ago

I use M-q (fill-paragraph) quite a bit when modifying comments in source files.

Not sure why you were downvoted.

tjr2• 15 years ago

M-q is admittedly not very interesting. Just useful. :-)

pmr_• 15 years ago

Enter auto-fill-mode.

bitstream• 15 years ago

The kill ring gets my vote.

Regional undo/redo is a close second.

ordinary• 15 years ago

This is not really a feature, as such, but it is a classic work-around for one emacs' many silly defaults:

            ; Ask for y/n on all queries that normally ask for yes/no.
  (fset 'yes-or-no-p 'y-or-n-p)

tikhonj4• 15 years ago

I personally don't think that default is silly. I've noticed that some (usually less important) questions use y or n already; the yes/no is reserved for important ones. I don't mind having to type a bit more before recursively deleting a directory, for example.

jrockway7• 15 years ago

I do this, but defalias is a better choice for implementing it than fset.

jlongster• 15 years ago

`ansi-term` is probably is for me. Integrating your terminal closer with your editor is really amazing. Using `multi-term` to make it easier to handle multiple terminals, and you've got a really nice integrated environment.

That's probably the killer feature for me.

SonicSoul• 15 years ago

on a side note, whenever i asked such open ended question on stackoverflow, it would quickly get closed by some other user claiming that "there is no right answer" and the question must be closed. But there are so many great open ended questions on there that score so high among users. i guess it's a matter of luck that some anal retentive person doesn't get to it first?

JeremyBanks• 15 years ago

It's not exactly luck. Until today this question hasn't been active since 2009, when opened-ended questions were permitted. Now that it's been bumped it'll be closed shortly.

smackfu• 15 years ago

Closed now.

I'm actually surprised that someone hasn't gone through all the older questions looking for stuff to close, given how rigid their mods tend to be.

michaelty• 15 years ago

C-x C-t

Transpose the current line with the previous line.

xtacy• 15 years ago

I like idomenu, which lists variable/function definitions in your file. When you combine it with ido-menu, it's magic. Bind it to C-c s, and you get a list of symbols you can navigate extremely fast.

The downside is that if the symbol locations change in a file, you'd have to refresh it. :(

thurn• 15 years ago

Sorry, is there a typo in here somewhere? Are "idomenu" and "ido-menu" different things?

markbao• 15 years ago

For Vim users like myself, there's a related Stack Overflow Discussion: What is your most productive shortcut with Vim?

http://stackoverflow.com/questions/1218390/what-is-your-most...

rryan• 15 years ago

The very phrasing of these two questions highlights the philosophical differences between emacs and vim: "feature" vs. "shortcut".

noelwelsh• 15 years ago

The single most useful Emacs feature is the design of Emacs as a platform for hosting ELisp. Without ELisp, and the OS and text editing services provided by the Emacs run-time, none of these extensions would be possible.

Trite but true!

veyron• 15 years ago

C-x C-c is to exit :)

mmc• 15 years ago

Too hard to pick one, it depends on the task. Maybe I'd go with M-x Occur. Other candidates are regex i-search, registers, yasnippet, kill/copy/(insert)string-rectangle, etc etc.

Also, emacsclient.

paddy_m• 15 years ago

for me it has to be comint mode and every mode that wraps comint. I run M-x shell all the time, being able to use all my favourite editing commands to go back through shell history is just killer.

plq• 15 years ago

I thought StackOverflow was done with such poll-type questions? I was sorry to see the "Best Programming Comics" question go.

calibraxis• 15 years ago

Undo-tree handles all my undo'ing needs, and non-emacs users like looking at its strikingly elegant tree visualizer.

(http://www.emacswiki.org/emacs/UndoTree) Scroll down for screenshot.

And follow-mode on a monitor turned sideways is pretty funny. Doubles your vertical space (good for eyeballing logs and data dumps).

justinhj2• 15 years ago

I use `self-insert-command' an awful lot. I'd say it was the single most important feature.

juanre• 15 years ago

It's interesting that it's hard to explain, because the fingers will play the chord by themselves and I need to stop and think to know what I am actually typing.

C-x r k to cut a rectangle, and C-x r t to add one filled with, for example, the comment symbol:

(C-space)this

to comment

C-x r t #

#this

#to comment

tikhonj4• 15 years ago

You can also use the M-x comment-region and M-x uncomment region to comment stuff. If you use it a lot, just bind them to a convenient key stroke.

mark_h2• 15 years ago

Don't forget M-; is comment-dwim which usually does... what you mean (uncomments the region if it looks commented, comments it otherwise)

draven• 15 years ago

and/or M-x comment-box

ludwigvan3• 15 years ago

I find cua-mode's rectangle support superior. http://trey-jackson.blogspot.com/2008/10/emacs-tip-26-cua-mo...

to3m• 15 years ago

Holy crap, thank you very much! Looks like cua-mode rectangle select might actually be the equal of Visual Studio's very straightforward rectangle selections...

gaving• 15 years ago

M-! open http://www.vim.org/

jbp• 15 years ago

- ido mode with ido-enable-flex-matching set. - recentf-mode integrated with ido. Too many to list.

RockyMcNuts2• 15 years ago

record and play macro (someone had to mention)

  C-x ( 
  <type some magic /> 
  C-x ) 
  C-x e

  M-x 99 C-x e

(play macro 99 times)

tikhonj4• 15 years ago

Also note that

    C-u 0 C-x e

plays the macro until it rings the bell (e.g. runs out of buffer space or tries to forward-search for a name that doesn't exist. This is great when you don't know how many times it needs to be run.

vedang• 15 years ago

^ This. super-useful under appreciated keyboard macro feature.

jrockway7• 15 years ago

M-x 99 C-x e (play macro 99 times)

Actually, that would be M-9 M-9 C-x e or C-u 99 C-x e.

RockyMcNuts2• 15 years ago

oops... yes, what you said. ie Esc 9 9 C-x e

parbo• 15 years ago

Undo in region saves me every day.

avar• 15 years ago

TRAMP. Being able to seamlessly remotely edit files and run remote modes.

At work I regularly edit files on 10-15 remote machines. But I never ssh to them and run an editor. Instead I'll just visit them through TRAMP, run Magit to commit stuff that I've done etc.

tikhonj4• 15 years ago

My coworkers often don't even realize I'm editing a remote file or working in a remote shell. It's really that seamless.

Of course, sometimes I forget I'm working remotely, and hilarity ensues. The worst episode was in a recent school project. I thought "oh, I'll just finish this on the train". And then, when I got on the train, realized I had actually been working remotely. Oops.

technomancy4• 15 years ago

> It's really that seamless.

Not only is it seamless editing, you can actually use tramp to "cd" into a directory on a remote machine using eshell.

rcthompson2• 15 years ago

Does magit actually work in git repos on remote servers?

Edit: Holy crap, it does. That's going to be useful.

thingie• 15 years ago

I use tramp as well, but can't say I like it. Blocking whole UI because of network problems, leaving garbage in the shell history on the machines I'm connecting to, getting confused (and hung-up) by different prompts. It's nice, but too volatile.

jfb3• 15 years ago

The kill ring. I would marry the kill ring and have its babies. Why have other editors not adopted this? Have they?

billswift• 15 years ago

I wish the Windows Clipboard would implement a version of the kill ring. I really, really hate not having previous cuts and copies available. As a rather clumsy work-around I keep an emacs scratch file open on my task bar and copy stuff I might need more than once to it.

jfb3• 15 years ago

Same with the Mac clipboard.

hn_reader• 15 years ago

The ditto clipboard manager for Windows http://ditto-cp.sourceforge.net/ has completely solved this problem for me.

jharsman• 15 years ago

Sounds like you want XKeymacs it gives Emacs keyboard commands to all Windows applications, including a kill ring.

http://www.cam.hi-ho.ne.jp/oishi/indexen.html

winestock• 15 years ago

Look up Clipboard Manager by Jan Zeman. It runs in the Windows sidebar.

wwkeyboard• 15 years ago

I've had success with http://jumpcut.sourceforge.net/ before. I just have been using emacs for almost everything so have not tried this with Lion.

JadeNB• 15 years ago

As best I understand the emacs functionality, vim's numbered registers are its analogue: http://vimdoc.sourceforge.net/htmldoc/change.html#registers.

lucaspiller2• 15 years ago

I haven't used Emacs, but I've worked with people who have, and the one thing that made me think 'wow' was this. So many times have I yanked something, deleted some white space or some such, and then lost it.

If (like me) you are a Vim user, there is a plugin to replicate this functionality called YankRing. Highly recommended! http://www.vim.org/scripts/script.php?script_id=1234

Derbasti3• 15 years ago

The register 0-9 store the last ten deletes (yanks?) in Vim.

Derbasti3• 15 years ago

The register 0-9 store the last ten deletes (yanks?) in Vim. This serves the same purpose as the kill ring.

ww5202• 15 years ago

Breadcrumb for Emacs

T_S_• 15 years ago

Ctrl-k

Semiapies3• 15 years ago

It's definitely up there for me, which I find amusing as I thought it was such an odd action to mention early in tutorials - and yet it's so damn handy once you get get it in muscle memory.

gnuvince2• 15 years ago

`C-u SPC` which pops the mark. This allows you to go back to different places in your buffer quickly. For example, if you are editing a program and need to add an import statement, you could do it like this: `C-SPC M-< [add your import] C-u SPC` and you'll be back to where you were editing.

If you are using transient-mark-mode, you can use `C-SPC C-SPC` to active and deactive the highlighted region. That'll still leave a mark.

basman• 15 years ago

The nice thing is that many commands set the mark automatically. So in your example, there's no need for the initial C-SPC.

gnuvince2• 15 years ago

True. I've just gotten into the habit of doing it manually in case I use a command that doesn't do it.

etfb2• 15 years ago

I love how every post on Stack Overflow that gets popular on Hacker News always gets closed by SO admins as "not constructive". It's like they really are annoyed when their stuff gets noticed by the world outside their walled garden. What are they - hipsters? "I was a fan of internet startups before they got popular, dude." It's bad enough on Wikipedia, which appears to operate on the principle that a megabyte of hard disk still costs $100, but on Stack Overflow it's just plain foolish.

thristian2• 15 years ago

Less cynically, Stack Overflow is about specific answers to specific questions. Any question broad enough to be interesting to a site like Hacker News is too broad for Stack Overflow, apparently.

etfb2• 15 years ago

Makes sense, but it's insane. More general answers are more generally useful than specific ones, by definition.

kabdib• 15 years ago

Keyboard macros.

Multiple buffers, and windows against them.

Followed closely by mode-specific buffers (c-mode, etc.).

Buffers with command shells are the bee's knees. I love those things.

Semiapies3• 15 years ago

For newcomers, C-g is a delight (it certainly was for me). Especially with the arcane reputation of Emacs, it was awfully reassuring to know how to get out of whatever unfamiliar function I'd fat-fingered myself into.

jrockway7• 15 years ago

Well, it won't get you out of recursive edits. I remember visiting a coworker's machine before telling him about those, and the modeline was something like [[[[[[[[[[(CPerl)]]]]]]]]]].

ESC ESC ESC is a much better "get me out of here!" command to remember.

Semiapies3• 15 years ago

I haven't managed to get into such a position; I may not be as clever as your coworker.

einhverfr• 15 years ago

Hard to argue with C-x C-s being the most useful feature of EMACS......... It's so useful people take it for granted ;-)

The single most useful Emacs feature

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