articles/vi.md: add cheatsheet

articles/vi.md

@@ -13,6 +13,144 @@ tutorial with the `:Tutor` *editor* command.
 
 TODO
 
+## Cheatsheet
+Some of these can be prefixed with a register name and a count number (in that order).
+Commands that work with registers use by default an anonymous registers if none is explicitly specified.
+
+`c`: command mode, `i` = insert mode; `v`: visual mode; `n`: normal mode.
+
+### Basics
+- `:e`: open file in a new buffer, file needn't exist
+- `:w`: save current buffer
+- `:wa`: save all modified buffers
+- `:wq`: save current buffer and exit
+- `:wqa`: same as above, but all buffers
+- `:x`: same as `:wq`, saves only if buffer was changed
+- `:q`: quit
+- `:q!`: quit without saving current buffer
+- `:qa!`: quit regardless anything
+- `:new`: open empty buffer as split window
+- `:enew`: open empty buffer in current window
+
+### Common operations
+- (c,i,v) `<Esc>`: escape from insert, visual modes to normal mode.
+- (n) `w`: Jump to next word
+- (n) `e`: Jump to the end of the current word (and of the next one if you keep pressing it)
+- (n) `b`: Jump to previous word
+- (c,i) `Ctrl-n`: move to the next item in the completion menu
+- (c,i) `Ctrl-p`: move to the previous item in the completion menu
+- (c,i) `Ctrl-y`: confirm current selection
+- (i): `Ctrl-o`: temporarily exit insert mode to normal mode; goes back to insert mode after
+a command or normal mode binding was executed.
+- (n): `Ctrl-e`: scroll a line forward
+- (n): `Ctrl-y`: scroll a line backwards
+- (n): `Ctrl-f`: scroll a page **f**orward
+- (n): `Ctrl-b`: scroll a page **b**ackwards
+- (n): `Ctrl-o`: moves to previous position
+- (n): `Ctrl-i`: moves to next position
+- (n) `d`: delete [works with registers, prefix count, movement]
+    - `dd`: delete current line
+    - `"add`: delete current line to the register `a`
+    - `9dd`: delete 9 lines (last `d` can also be a movement like `j` or `k` to control the direction)
+    - `dk`: delete current line and the one above
+    - `dj`: delete current line and the one under
+- (n) `y`: yank (copy) [works with registers, prefix count]
+    - `yy`: yank current line
+    - `"ayy`: yank current line to the register `a`
+    - `yk`: yank current line and the one above
+    - `yj`: yank current line and the one under
+    - `"+yy`: yank current line to the system clipboard
+    - `9yy`: yank 9 lines (last `y` can also be a movement like `j` or `k` to control the direction)
+- (n) `p`: paste after cursor [works with registers, prefix count, movement]
+    - `"ap`: paste from `a` register
+    - `4p`: paste from anonymous register 4 times
+    - `"a4p`: paste from `a` register 4 times
+- (n): `P`: paste before cursor [works with registers, prefix count, movement]
+- (n) `r`: Replace a single character under the cursor
+- (n) `x`: Delete character under the cursor [works with registers, prefix count]
+    - `2x`: delete two characters
+- (n) `X`: delete character before the cursor
+- (n) `c`: change, roughly equivalent to a combined delete and insert
+
+### Mode changing
+- (n) `i`: Enter insert mode after the cursor
+- (n) `I`: Enter insert mode, at the start of the line
+- (n) `a`: Enter insert mode before the cursor
+- (n) `A`: Enter insert mode at the end of the line
+- (n) `o`: Enter insert mode, adding a newline under
+- (n) `O`: Enter insert mode, adding a newline above
+- (n) `R`: Enter replace mode
+- (n) `v`: Enter visual mode
+- (n) `V`: Enter visual line mode
+- (n) `Ctrl-v`: Enter visual block mode
+
+### Movement keys [can be prefixed with count]
+It has to be noted that `Home`, `End`, `PageUp/Down` and cursor keys also work.
+
+- (n) `h`: Move left
+- (n) `j`: Move down
+    - `4j`: Move 4 lines down
+- (n) `k`: Move up
+- (n) `l`: Move right
+- (n) `0`: move to start of line
+- (n) `^`: move to first non-whitespace character of line
+- (n) `$`: move to the end of the line
+- (n) `f`: move to specified character, forwards
+    - `fe`: move to `e`
+- (n) `F`: move to specified character, backwards
+
+### Searching
+- (n) `/`: search for pattern, forwards
+- (n) `?`: search for pattern, backwards
+
+### Other
+- (n) `~`: change case of current character under the cursor
+- (v) `u`: lowercase the current selection
+- (v) `U`: uppercase the current selection
+- (n) `q:`: open command-line history window, here you can edit the commands and execute them with enter.
+- (n) `q/`: search pattern history
+- `:help`, `:h`: Vim help pages
+
+### Windows (splits)
+- `:vs`: create vertical split
+- `:sp`: horizontal split
+- `:sb`: open buffer as window
+- (n) `Ctrl-w q`: close window (buffer remains open)
+- (n) `Ctrl-w w`: cicle though opened windows
+- (n) `Ctrl-w =`: make windows have the same width
+- (n) `Ctrl-w s`: split current window horizontally
+- (n) `Ctrl-w v`: split current window vertically
+- (n) `Ctrl-w +`, `Ctrl-w -`: increase/decrease height of window
+- (n) `Ctrl-w <`, `Ctrl-w >`: change width of window
+
+### Undo-redo
+- (n) `u`: undo
+- (n) `Ctrl-r`: redo
+- (n) `g+`: go to newer undo tree state (see `:h undo-tree`)
+- (n) `g-`: go to older undo tree state
+
+### Buffers
+- `:bd`: delete (quit) current buffer (file is not deleted)
+- `:bd!`: same but doesn't nag if the buffer wasn't been saved
+- `:bp`: go to previous buffer
+- `:bn`: go to next buffer
+- `:b#`: go to last buffer (`#` holds the last buffer ID)
+
+### "Go to" binds
+- `gg`: go to..
+    - `gg`: go to top of file
+    - `30gg`: go to line 30
+- `G`: go to bottom of file
+    - `30G`: same as `30gg`
+- `gT`: move to previous tab
+- `gt`: move to next tab
+- `gf`: open the file path under the cursor in a new buffer
+- `gx`: tries to open whatever is under the cursor with the system handler (for example, you can use this to open an URL)
+
+### Special registers
+- `+`: system clipboard
+- `*`: system's clipboard primary selection
+
 ## vi-like editors
 - Vim: vi improved, one of the most popular vi-like editors; includes a scripting language,
 VimScript for extending the editor.