You can't see invisible text in the buffer, but if you save the file, it'll be there. I want the oppsoite -- something to display, but if I save the file it won't be written to disk.
In particular I want to display an ellipsis (the "..." symbol) where I have hidden text.
In case it's relevant, here's the code where I'd like to do that. The "fold" function hides text, and the "unfold" function shows it again. The region folded or unfolded is every line just below the current one with more leading space than the current one.
If you set the invisible property to a custom symbol my-fold:
(put-text-property startRegion endRegion 'invisible
(if toHide 'my-fold nil))
You can say that my-fold invisibility should use an ellipsis:
;; Cause use of ellipses for invisible text.
(add-to-invisibility-spec '(my-fold . t))
Further reading:
C-hig (elisp)Invisible Text
C-hig (elisp)Replacing Specs
I copied this from somewhere, and it works well for scrolling one line at a time.
(setq mouse-wheel-scroll-amount '(1 ((shift) . 1))) ;; one line at a time
However, I don't understand the meaning of '(1 ((shift) . 1) here.
What does the shift do?
As with any variable in Emacs, use C-hv mouse-wheel-scroll-amount to learn about it.
In this instance I see:
mouse-wheel-scroll-amount is a variable defined in ‘mwheel.el’.
Its value is (5 ((shift) . 1) ((control)))
Documentation:
Amount to scroll windows by when spinning the mouse wheel.
This is an alist mapping the modifier key to the amount to scroll when
the wheel is moved with the modifier key depressed.
Elements of the list have the form (MODIFIERS . AMOUNT) or just AMOUNT if
MODIFIERS is nil.
AMOUNT should be the number of lines to scroll, or nil for near full
screen. It can also be a floating point number, specifying the fraction of
a full screen to scroll. A near full screen is ‘next-screen-context-lines’
less than a full screen.
Which is slightly technical, but is telling me that Emacs will scroll 5 lines at a time when I use the mouse wheel by default; but just 1 line at a time when I am holding shift; and if I am holding ctrl then it will scroll something close to a full screen at a time -- as ((control)) is the same thing as ((control) . nil).
The behaviour of:
(setq mouse-wheel-scroll-amount '(1 ((shift) . 1)))
is therefore equivalent to simply
(setq mouse-wheel-scroll-amount '(1))
as in the latter case, there are no overrides for modifier keys.
Is it possible to alter a variable while debugging?
Say for example I have this code:
string x = "foo"; //would actually be a passed-in variable in the real world.
var y = "X equals " + x;
==>[BREAKPOINT] return x;
Is there a way to manually enter or otherwise change the value of "x" when I hit the break point? Also , is it possible to "step back" in the code in the same way that you can press F11 and step through it?
Yes, there are 2 ways to change a variable:
Use the Immediate window. Simply typing x = "a new value" will change it. Also, if you want to check the value of x use ?x
You can hover over the variable, and when the value displays in the quickwatch pop-up thing, just click on it an manually change it. (You can also add the variable to watch, or select quickwatch to change it).
If you would like to step to a different instruction, there are 2 ways to do that too:
You can right-click on the line you want to go to and select 'Set next statement'. This even works if you have hit an exception while debugging
You can drag the yellow arrow that indicates the current instruction to wherever you need it
I'm trying to slightly enhance the find-tag function by always navigating to the default found tag.
As find-tag is, when I press M-. while the cursor being on a function name, emacs prints the following message:
Find tag (default fun_name):
And it waits for me to either press RET or go to another match. The thing is, I always press RET. So I just would like to skip that step by making emacs "press RET" automatically. I would like to automatically navigate to the function right after I press M-.
How can I set this behaviour from my .emacs file?
(defun sm-find-tag ()
(interactive)
(find-tag (funcall (or find-tag-default-function
(get major-mode 'find-tag-default-function)
'find-tag-default))))
What is the best way to move around on a given very long command line in the terminal?
Say I used the arrow key or Ctrl-R to get this long command line:
./cmd --option1 --option2 --option3 --option4 --option5 --option6 --option7 --option8 --option9 --option10 --option11 --option12 --option13 --option14 --option15 --option16 --option17 --option18 --option19 --option20 --option21 --option22 --option23 --option24 --option25 --option26 --option27 --option28 --option29 --option30 --option31 --option32 --option33 --option34 --option35 --option36 --option37 --option38 --option39 --option40 --option41 --option42 --option43 --option44 --option45 --option46 --option47 --option48 --option49 --option50
Now I need to move (starting from the beginning or the end of the line) the cursor to --option25 to modify something there.
What is the fastest way to get there? What I usually do is Ctrl-A to get to the beginning and then repeatedly Alt-F to move forward, word by word (or Ctrl-E to go the end and Alt-B to then go backward). But on a long line that takes too much time. There must be a way to search and jump directly to the part I need to modify, e.g. option25?
To be clear, you don't want a "fast way to move the cursor on a terminal command line".
What you actually want is a fast way to navigate over command line in you shell program.
Bash is very common shell, for example.
It uses Readline library to implement command line input. And so to say, it is very convenient to know Readline bindings since it is used not only in bash. For example, gdb also uses Readline to process input.
In Readline documentation you can find all navigation related bindings (and more):
http://www.gnu.org/software/bash/manual/bash.html#Readline-Interaction
Short copy-paste if the link above goes down:
Bare Essentials
Ctrl-b Move back one character.
Ctrl-f Move forward one character.
[DEL] or [Backspace] Delete the character to the left of the cursor.
Ctrl-d Delete the character underneath the cursor.
Ctrl-_ or C-x C-u Undo the last editing command. You can undo all the way back to an empty line.
Movement
Ctrl-a Move to the start of the line.
Ctrl-e Move to the end of the line.
Meta-f Move forward a word, where a word is composed of letters and digits.
Meta-b Move backward a word.
Ctrl-l Clear the screen, reprinting the current line at the top.
Kill and yank
Ctrl-k Kill the text from the current cursor position to the end of the line.
M-d Kill from the cursor to the end of the current word, or, if between words, to the end of the next word. Word boundaries are the same as those used by M-f.
M-[DEL] Kill from the cursor the start of the current word, or, if between words, to the start of the previous word. Word boundaries are the same as those used by M-b.
Ctrl-w Kill from the cursor to the previous whitespace. This is different than M- because the word boundaries differ.
Ctrl-y Yank the most recently killed text back into the buffer at the cursor.
M-y Rotate the kill-ring, and yank the new top. You can only do this if the prior command is C-y or M-y.
M is Meta key.
For Max OS X Terminal you can enable "Use option as meta key" in Settings/Keyboard for that.
For Linux its more complicated.
Update
Also note, that Readline can operate in two modes:
emacs mode (which is the default)
vi mode
To switch Bash to use vi mode:
$ set -o vi
Personaly I prefer vi mode since I use vim for text editing.
Bonus
In macOS Terminal app (and in iTerm too) you can Option-Click to move the cursor (cursor will move to clicked position). This even works inside vim.
Since this hasn't been closed yet, here are a few more options.
Use Ctrl+x followed by Ctrl+e to open the current line in the editor specified by $FCEDIT or $EDITOR or emacs (tried in that order).
If you ran the command earlier, hit Ctrl+r for a reverse history search and type option25 (in this case). The line will be displayed. Hit Tab to start editing at this point.
Use history expansion with the s/// modifier. E.g. !-2:s/--option25/--newoption/ would rerun the second-to-last command, but replace option25. To modify the last ./cmd command, use the !string syntax: !./cmd:s/--option25/--newoption/
Any delimiter may be used in place of / in the substitution.
If editing the previous line, you can use quick substitution: ^--option25^--newoption
Character search. This was mentioned by Pax, and can be done in regular emacs-mode with Ctrl+] for forward search, and Ctrl+Alt+] for backward search.
I recommend the second option. Ctrl+r is really handy and fast, no mucking about with editors, and you see the results before the command is run (unlike the history expansions).
Hold down the Option key and click where you'd like the cursor to move, and Terminal rushes the cursor that precise spot.
I tend to prefer vi editing mode (since those keystrokes are embedded into my spinal cord now (the brain's not used at all), along with the CTRL-K, CTRL-X from WordStar 3.3 :-). You can use the command line set -o vi to activate it (and set -o emacs to revert).
In Vi, it would be (ESC-K to get the line up first of course) "f5;;B" (without the double quotes).
Of course, you have to understand what's on the line to get away with this. Basically, it's
f5 to find the first occurrence of "5" (in --option5).
; to find the next one (in --option15).
; to find the next one (in --option25).
B to back up to the start of the word.
Let's see if the emacs aficionados can come up with a better solution, less than 5 keystrokes (although I don't want to start a religious war).
Have you thought about whether you'd maybe like to put this horrendously long command into a script? :-)
Actually, I can go one better than that: "3f5B" to find the third occurrence of "5" then back up to the start of the word.
Use Meta-b / Meta-f to move backward/forward by a word respectively.
In OSX, Meta translates as ESC, which sucks.
But alternatively, you can open terminal preferences -> settings -> profile -> keyboard and check "use option as meta key"
After running the command once, run fc
It will launch $EDITOR with the previous command, then you can use your regular editor to modify the command. When you save and exit, the file will be executed.
..but, as Pax said - the command line isn't particularly good for editing absurdly long lines - why not make the command into a script?
If you want to move forward a certain number of words, hit M-<n> (M- is for Meta and its usually the escape key) then hit a number. This sends a repeat argument to readline, so you can repeat whatever command you want - if you want to go forward then hit M-<n> M-f and the cursor will move forward <n> number of words.
E.g.
$|echo "two three four five six seven"
$ M-4
(arg: 4) echo "two three four five six seven"
$ M-f
$ echo "two three four| five six seven"
So for your example from the cursor at the beginning of the line you would hit, M-26 M-f and your cursor would be at --option25| -or- from the end of the line M-26 M-b would put your cursor at --|option25
Incremental history searching
in terminal enter:
gedit ~/.inputrc
then copy paste and save
"\e[A": history-search-backward
"\e[B": history-search-forward
"\e[C": forward-char
"\e[D": backward-char
all you need to do to find a previous command is to enter say the first 2 or 3 letters and upward arrow will take you there quickly say i want:
for f in *.mid ; do timidity "$f"; done
all i need to do is enter
fo
and hit upward arrow command will soon appear
It might not be the fastest, but this need to be here, some reading about ANSI cursor movements
ANSI escape sequences allow you to move the cursor around the screen at will. This is more useful for full screen user interfaces generated by shell scripts, but can also be used in prompts. The movement escape sequences are as follows:
- Position the Cursor:
\033[<L>;<C>H
Or
\033[<L>;<C>f
puts the cursor at line L and column C.
- Move the cursor up N lines:
\033[<N>A
- Move the cursor down N lines:
\033[<N>B
- Move the cursor forward N columns:
\033[<N>C
- Move the cursor backward N columns:
\033[<N>D
- Clear the screen, move to (0,0):
\033[2J or \033c
- Erase to end of line:
\033[K
- Save cursor position:
\033[s
- Restore cursor position:
\033[u
(...)
Try putting in the following line of code at the prompt (it's a little clearer what it does if the prompt is several lines down the terminal when you put this in): echo -en "\033[7A\033[1;35m BASH \033[7B\033[6D" This should move the cursor seven lines up screen, print the word " BASH ", and then return to where it started to produce a normal prompt.
Examples:
Move the cursor back 7 lines:
echo -e "\033[7A"
Move the cursor to line 10, column 5:
echo -e "\033[10;5H"
Quickly echo colors codes, to colorize a program:
echo -e "\033[35;42m" ; ifconfig
using option key and using a click the place you want to place the cursor with mouse or touchpad is you are using Mac build-in terminal.
One option is to use M-x shell in emacs. That provides all editing facilities and keystrokes that emacs has, so C-s can be used to search the text option25, for example.
(But I'd still prefer to be in the real terminal shell instead if someone can point me to good search and edit facilities.)
Use the mouse
Sometimes, the easiest way to edit a commandline is using a mouse. Some previous answers give a command to open your current line in your $EDITOR. For me (zhs with grml config) that combination is Alt+e. If you enable mouse in your editor, you can make use of it.
To enable mouse in Vim, add this to your ~/.vimrc
set mouse=a
set ttymouse=xterm2
If you then want to do a text selection in terminal (instead of passing the mouseclick to vim), hold Shift when you click; this is terminal specific, of course.
Sysadmins should not be afraid of the mouse.
In Cygwin, you can activate such feature by right-clicking the window. In the pop-up window, select Options... -> Mouse -> activate Clicks place command line cursor -> Apply.
From now on, simply clicking the left mouse button at some position within the command line will place the cursor there.
first:
export EDITOR='nano -m'
then:
CTRL+X CTRL+E in sequence.
You current line will open in nano editor with mouse enable. You can click in any part of text and edit
then CTRL+X to exit and y to confirm saving.
I made a script to make the command line cursor move on mouse click :
Enable xterm mouse tracking reporting
Set readline bindings to consume the escape sequence generated by clicks
It can be found on github
More info on another post
Will work if echo -e "\e[?1000;1006;1015h" # Enable tracking print escape sequences on terminal when clicking with mouse