Emacs as Your IDE
This is a no-frills listing towards using Emacs as a development environment. C-x means CTRL-x. M-x means ALT-x (or ESC and then x).
You can press the TAB key almost anywhere for autocompletion. Wherever you input text, use M-p and M-n to traverse up and down the history list.
C-u is the numeric-prefix operator. To go up by 10 lines, for example, one would say C-u 10 C-p.
Stuck!
- Exit Emacs: C-x C-c
- Cancel command: C-g
File Handling
- Open a file: C-x C-f (Remote file: /user@host:path/to/file via ftp)
- Change to a directory: C-x d
- Save file: C-x C-s
- Save as: C-x C-w
- Close a file (kill buffer): C-x k
- Reload file: C-x C-v
- Change to another open file: C-x b
- List all open files (buffers): C-x C-b
- Maximise a window: C-x 1
- Switch to the other window: C-x o
Editing
- Start marking: C-<SPACE> (Use arrow keys to select region)
- Cut: C-w
- Copy: M-w
- Paste: C-y (previous: M-y)
- Undo: C-x u
- Delete word: M-d
- Complete word: M-/
- Open a new line: C-o
- Kill upto end of line: C-k (Is appended to clipboard)
- Indent current line to GNU C standard: <TAB>
- Toggle read-only: C-x C-q
- Paragraph-ise current region: M-q
- Spell-check current word: M-$ (whole file: M-x ispell)
Search/Replace
- Search forward: C-s (Press C-s to search again)
- Search backward: C-r
- Search all or some open buffers: M-x multi-occur-in-matching-buffers
- Search and replace: M-%
- List occurrences: M-x occur
- Run grep: M-x rgrep (try it, it's way cool!)
- Reg-ex search: C-M-s
[XKCD pays tribute to Emacs]
Navigation
- Beginning of file: M-<
- End of file: M->
- Jump back to where you were from beginning/end: C-u C-<spc>
- Beginning of line: C-a
- End of line: C-e
- Previous word: M-b
- Next word: M-f
- Previous matching bracket: C-M-b (if it doesn't work, try ESC followed by C-b)
- Next matching bracket: C-M-f (or ESC C-f)
- Go to start of block: C-M-u
- Go to end of block: C-M-d
- Start of #ifdef: C-c C-p
- End of #ifdef: C-c C-n
- Start of function: C-M-a
- End of function: C-M-e
- Outline mode: C-u 1 C-x $ (C-x $ to revert)
- Newspaper mode: C-x 3 M-x follow-mode (especially useful with today's wide-screen monitors!)
- Go to line: M-g (or M-x goto-line)
The arrow area is so far away!? - Previous line: C-p
- Next line: C-n
- Previous character: C-b
- Next character: C-f
- Page Up: M-v
- Page Down: C-v
A lot of productivity comes out of being able to ignore irrelevant code, so these keys should become second-nature.
Vertical Copy
Sometimes you will need to copy a vertical patch of data, e.g. one column in a table. First press C-<space> where you want to start copying. Then go to the end of the column and press C-x r k. To paste the column press C-x r y. (If you don't want to delete original column, just press C-_ there once to restore it and then press C-x r y at target.)Registers
- To save the current location in register a: C-x r <SPC> a
- To jump to the location in register a: C-x j a
- To list saved registers: C-x r l
Symbol Lookup
Assuming CODEDIR to be the top-level source directory, first update your ~/.bashrc like so:alias mktags='cd $CODEDIR && etags `find $CODEDIR -name "*.[h|c]"` && cd -'
Then run:
source ~/.bashrc mktags
When Emacs asks for the TAGS file, specify $CODEDIR/TAGS.
- Go to function/variable definition: M-. (M-* to return)
- Next definition of the tag: C-u M-. (e.g. same method in multiple classes)
- Search for occurrences of symbols: M-x tags-search (M-, to search forward)
- Find symbols as reg-exps: M-x find-tag-regexp
- Autocomplete symbol: M-<TAB>
Compilation and Debugging
- Compile: M-x compile
- Stop compilation: C-c C-k
- Go to next error: C-x `
- Go to source line giving the error: C-c C-c
- Debug with GDB: M-x gdb
- Insert breakpoint: C-x <SPACE>
- Run a shell command: M-! (C-u M-! to insert output)
- Open a shell: M-x shell
(setq compile-command "gmake -f Makefile.gnu all")
Comparing Two Files
- Start a diff session: M-x ediff
- Next match: n
- Previous match: p
- Copy from file A to B: a
- Copy from file B to A: b
- Save file X: wX
- See diff output: D
- Ignore whitespace differences: ##
- Compare directories: M-x ediff-directories
Keyboard Macros
- Begin recording: C-x (
- End recording: C-x )
- Execute macro: C-x e
Go to the first prototype, and say:
C-x ( C-a extern<SPACE> C-n C-x )Then say C-u 50 C-x e to replace 50 prototypes.
Perforce CVS Integration
Get p4.el and then follow these steps.$ emacs -batch -f batch-byte-compile p4.el
Put the p4.el in some directory, say /home/foo/bar. Then edit your ~/.emacs as follows:
(setq load-path (cons "/home/foo/bar" load-path)) (load-library "p4")
You should see a P4 menu in Emacs, and you can do CVS operations from within Emacs now.
Symbol Lookup with cscope
Download cscope program, and xcscope.el and cscope-indexer from some place. Save the xcscope.el onto some directory in Emacs' load-path. Edit your ~/.emacs as follows:(require 'xcscope)To add a directory ~/foo to your load-path, use the following directive in .emacs file, making sure it appears before the "require xcscope" directive:
(setq load-path (cons "~/foo" load-path))
Place cscope-indexer in your $PATH. You can then use these keystrokes while browsing C source code:
- Index files: C-c s I
- Find global definition: C-c s d
- Find symbol definition: C-c s s
- Find this file: C-c s f
- Find functions calling this function: C-c s c
- Find functions called by this function: C-c s C
- Find this pattern: C-c s e
- Find this text string: C-c s t
- Find files including this file: C-c s i
Java
cscope can be used to browse Java symbols too. Use these commands at the top-level directory to create the index:find . -name "*.java" > cscope.files cscope -bThen add this line at the bottom of xcscope.el to load cscope-mode whenever a Java file is opened:
(add-hook 'java-mode-hook (function cscope:hook))
File Operations
Operations such as move, copy, delete etc. are available in the directory editor: M-x diredCalculations
- Built-in calculator: M-x calculator
- Change input base: i (b | o | h)
- Change output base: o (b | o | h)
More Help
- Built-in tutorial: C-h t
- Info reader: C-h i
