Is it possible to select part of a string in the bash terminal and delete it at once, rather than navigating to a point in the command and backspacing it all??
thanks!
I'm not 100% sure I understand your question.
If you are at the interactive command line:
ctrl-u: Deletes everything to the left of your cursor
ctrl-k: Deletes everything to the right of your cursor
I'm using emacs bindings and my favourite command line shortcuts, which were not included in the previously linked tutorial, are the following:
^W - delete last word
meta-b - move cursor back one word
^R - find a previously used command
!$ - last attribute of the last command
!! - last command
You can also manipulate the history with regexps, although that could quickly get quite messy. See "man zshexpn" for reference, mostly the same regexp syntax works for bash also.
Example:
1) If you execute the following command:
echo first second third fourth fifth
2) Then you could execute the same command and remove "first" by:
!!:s/first//
If this was not what you were after, please clarify on your question! :)
See this. Alternatively, set -o vi to have vim-like key bindings.
Note that the list given in the link is not full. You might read man bash for a good reference. Usually, ALT-x might be replaced by ESC, x if you run bash inside a terminal that uses Alt-letter shortcuts for windowing system.
Related
There seems to be quite a lot of information on how to edit and execute a command using your editor using "edit-and-execute-command (C-x C-e)", but what I would like to achieve is take the current shell command, apply certain filtering (using a script) and then return it to prompt for further approval/manual changes before execution. Is this possible with bash?
Latest update based on my experience
The part 0"+y$dd in the following mapping is really something that you should carefully think about and tailor it to your taste/workflow/experience.
For instance, very frequently I've found myself ending up with multiple lines in the buffer, where I only want to execute the one the cursor is on; in this case I can use 0"+y$dd:%d<CR> instead of 0"+y$dd.
And this is just one of the possible scenarios.
Final answer for those who like vim
Set vim as your EDITOR/VISUAL, so that when editing a command line, you will use vim to edit it.
Put au BufEnter /tmp/bash-fc.* nn <Leader>d 0"+y$dd:wq<CR> in your ~/.vimrc file to map Leaderd (which you will rarely use when editing a command) to the action "delete the current line into the + register without the trailing EOL".
you can use either the + or the * register in the mapping above; the ways to paste into the terminal will likely differ; you need the +clipboard option for these registers to be available.
When finished editing a command in the vim editor, hit EscapeLeaderd.
Paste the clipboard into the terminal (this is terminal-dependent).
Original answer
I often need to do the same, and I do it as follows. (I normally use the set -o vi in bash, so points 1 and 2 in the following are different if you use set -o emacs, the default; based on your question it looks like points 1 and 2 are unified in Ctrl+x followed by Ctrl+e, which is harder to type, imho.)
hit Escape to be in normal mode,
hit v to enter the editor to edit the command,
edit the command as I like,
(This is where you ask the question.)
hit Escape0"+y$dd:wq,
Note: 0"+y$, not simply "+yy, as the latter would copy the newline too, and this would result in executing the command upon pasting it in the command line,
paste the clipboard on the command line
how to do this depends on the terminal you are using, I guess; I hit Ctrl+Alt+v in URxvt.
proceed to approval/manual edit.
Clearly this is just a workaround, consisting in copying the edited command into the clipboard before deleting the whole command, so that nothing gets executed upon exiting the editor; however it's the best I can get for myself.
Update
As my EDITOR (and VISUAL) is equal to vim, when I edit the command, I edit it in vim.
In this respect, I have noticed that the buffer is named /tmp/bash-fc.random, where random is a 6-characters alphanumeric random string.
This gives space to a lot of possiblities, if you use vim as your editor, as you can define some mapping in your .vimrc to execute the whole sequence Escape0"+y$dd:wq. For instance, one command that you'd rarely use when editing a command line is Leaderd; therefore you can put the following mapping in your .vimrc file
au BufEnter /tmp/bash-fc.* nn <Leader>d 0"+y$dd:wq<CR>
so that step 4 in the above recipe becomes
hit EscapeLeaderd
It's not possible to do that in Bash/readline but it's possible in zsh
using edit-command-line command:
darkstar% autoload edit-command-line; zle -N edit-command-line
darkstar% bindkey "^X^E" edit-command-line
Now press Control-x Control-e to open your editor, edit line, leave the editor - you will see the updated command line but it will not be executed automatically.
Now that I think about it, maybe a variation of what #kenorb suggested in a comment is the best workaround (as it seems no solution exists), if we want to stick to bash.
What you can do is prepend a # (the comment character in bash) to the command, rather than echo. Then when you exit the editor, the command will be ineffective, and you will only have to press arrow up (or k, if you use set -o vi), remove the # and confirming.
Note that this strategy adds just a few keystrokes, so it can be fairly efficient, depending on your typing level.
These pieces might get you closer:
a) replace the the normal binding for newline newline (ctrl-M)
bind -x '"\C-M":date"
b) grab the current line from the history using !#
replace date with whatever script you want.
c) edit manually
d) if necessary, somehow tie in !!:p which prints the new command to the command line but does not execute it, thus letting you manually edit it.
e) using ctrl-J submit edited command rather than a newline
or they might not ....
There is an option in bash to modify command from history without executing it. I'm not sure it it's possible to use script for this, doesn't seem to be likely. Although, you can make modifications using history modifiers.
Enable option histverify to prevent execution of modified command
Use chain of modifiers to change last command
Use "!!" to put your result to command line for final edit
Here is how it looks:
$ shopt -s histverify
$ ls *.sh
script1.sh script2.sh script3.sh script-return.sh
$ !!:s/*/script1/:p
ls script1.sh
$ !!:s/1/2/:p
ls script2.sh
$ !!
$ ls script2.sh
script2.sh
I'd like to point you to the Composure framework for Bash (I'm not affiliated with it): https://github.com/erichs/composure
It provides draft and revise functions that sound like they could help with what you're trying to do. Here's a (long) quote from the project's readme file:
Composure helps by letting you quickly draft simple shell functions,
breaking down your long pipe filters and complex commands into
readable and reusable chunks.
Draft first, ask questions later
Once you've crafted your gem of a command, don't throw it away! Use
draft () and give it a good name. This stores your last command as a
function you can reuse later. Think of it like a rough draft.
$ cat servers.txt
bashful: up
doc: down
up-arrow
$ cat servers.txt | grep down
doc: down
$ draft finddown
$ finddown | mail -s "down server(s)" admin#here.com
Revise, revise, revise!
Now that you've got a minimal shell function, you may want to make it
better through refactoring and revision. Use the revise () command
to revise your shell function in your favorite editor.
generalize functions with input parameters
add or remove functionality
add supporting metadata for documentation
$ revise finddown
finddown ()
{
about finds servers marked 'down' in text file
group admin
cat $1 | grep down
}
$ finddown servers.txt
doc: down
It does not seem possible with a keyboard shortcut, at least:
$ bind -P | grep -e command -e edit
complete-command can be found on "\e!".
edit-and-execute-command can be found on "\C-x\C-e".
emacs-editing-mode is not bound to any keys
possible-command-completions can be found on "\C-x!".
vi-editing-mode is not bound to any keys
This can be done in native bash using readline specifically READLINE_LINE and READLINE_POINT variables. I use this functionality all the time though not through vim, you would need to get the value of $selected from your vim command and if not empty it takes your original line + your input and replaces your original line with the combination without executing. output as a variable
_main() {
selected="$(__coms_select__ "$#")"
origonal_text=$READLINE_LINE READLINE_LINE="${READLINE_LINE:0:$READLINE_POINT}$selected${READLINE_LINE:$READLINE_POINT}"
READLINE_POINT=$(( READLINE_POINT + ${#selected} ))
}
bind -m emacs-standard -x '"\C-e": _main '
bind -m vi-command -x '"\C-e": _main '
bind -m vi-insert -x '"\C-e": _main '
Edit
Just remembered these two utilities that will let you do this as well.
Vipe allows you to run your editor in the middle of a unix pipeline and edit the data that is being piped between programs.
vp, up, vipe, Neomux (upgrade of nvim terminal) you can do some pretty neat throwing buffers between the terminal and split window.
and Athame (full vim on the command line)
https://github.com/ardagnir/athame
careful with that one though plugins work on the cli and it can get funky if you got tons of plugins
There is an annoying difference between zsh and bash tab completion:
Imagine you write some command and want to add something at the beginning of the line:
$ compute --some --stuff
then you jump to the beginning of the line and line and start to write sudo (bad example - just to demonstrate)
$ sudcompute --some --stuff
^ <---cursor
bash would let you complete sud to sudo while zsh would try to complete sudcompute.
So in this case you would have to write a space, jump back one character and try to tab-complete.
In case you're still used to bash you would try to tab-complete after sud and render the command you started to write into something utterly useless.
So for short: is there an option to let zsh complete the phrase to the left of the cursor regardless whether or not it's terminated by a space?
Just looked around in my .zshrc file and I think this is what you want:
bindkey '^i' expand-or-complete-prefix
Where ^i is <Ctrl-I> which is usually tab.
While navigating in BASH using VI mode, I can jump back to a specific character (e.g. '-') of the current command line via the following command:
F-
How can I jump back to a specific string (e.g. '--path') in the current command line of BASH? I know navigating in VI but I did not understand how to perform regex search in current command line of BASH.
According to here, what you want doesn't seem possible. The ?word and /word bindings search in command history rather than in the current command line.
But in vi mode, you can press ESC v to open the current command line in an editor. Then you can edit & save the command and it will be executed (source).
Of course, as pointed out in nur-sh's answer, you can simply keep pressing B to get to the word.
You could use the find command which searches backwards from where you are
?word
or you could keep pressing B to get to the word
(this command goes back one Word at a time).
I've just started using Terminal (the CLI for Mac OS X).
When I run a command, get some information back, run another command, get more info etc., it is hard (on the eyes) to find a certain point on the screen (e.g. the output for the command before last).
Is there a way of adding a vertical empty space to the end of each output/ after each command is run that has no output?
Each new command that you enter is preceded by a "prompt", and these can be customized (though the exact way to customize depends on the shell). Since you mention Mac OS X I'm assuming you are using the default bash shell, in which case the absolute simplest way to add a blank line is like this: PROMPT_COMMAND=echo. You can run that command to try it out, or add it to a startup file (like .profile in your home folder) to have it done automatically each time.
If you use Bash 4.4 and you want a blank line after your prompt, you could set the PS0 prompt to a newline:
PS0="\n"
Now, this will be inserted every time you run a command:
$ echo "Hello"
Hello
Wondering this too, I've looked at the menu options in Terminal & most of the control characters one can type in and nothing does this on a keystroke. You can however enter an echo command, it alone to leave a single blank line below it before the next prompt. echo \n will add an extra blank line to that, echo \n\n to do 2 extra, ie. 3 blank lines, etc. (you can also do echo;echo;echo getting the same effect)
You can create a shell alias like alias b='echo;echo' (i couldn't seem to get the \n notation to work in a alias), then entering b on a prompt will leave a double-blank line, not bad. Then you gotta figure out how to save aliases in your .profile script.
I tried making an alias for the command ' ' ie. space character, which I though you could type like \ (hmm, stack overflow not formatting this well, that's backslash followed by a space, then return to execute it), but the bash shell doesn't seem to allow an alias with that name. It probably wouldn't allow a function named that either (similar to alias), though I didn't check.
I often use the fish shell, and I found that it does allow a function with that name! Created with function ' '; echo \n; end and indeed it works; at the shell prompt, typing the command \ (again backslash space) leaves a double blank line.
Cool, but.. I tried saving this function using funcsave ' ' (how you save functions in fish, no messing with startup scripts!) and afterwards the function no longer works :^( This is probably a bug in the fish shell. It's in active development right now though, I think I'll report this as a bug since I would kind of like this to work myself.
One could also send Apple a feature request through their bug reporter for an Insert Blank Line menu/keyboard command in Terminal. If someone pays attention to your request it might be implemented in a year maybe.
I wanted to solve exactly the same, and for anyone interested in doing the same, I used what tripleee said in his comment here - I created a .bash_profile (see details here) with the line export PS1="\n\n$ ".
Hopefully that helps someone else too!
I'd like to have a blank line after my bash prompt and before the output on my Mac. It should look like this would:
echo; ls
Can I add a newline to my bash prompt and then go back up one line to wait for user input? Is there something obvious I'm missing?
I know this is old but for someone like me who came across this while googling for it. This is how you do this...
It's actually pretty simple!
Check out this link --> Cursor Movement
Basically to move up N number of lines:
echo -e "\033[<N>A HELLO WORLD\n"
Just change the "< N >" to however many lines you want to go back...
For instance, to move up 5 lines it would be "/033[5A"
To my knowledge this is not possible unless you delve into more low-level stuff like full-screen emulators like curses.
This is a bit of a stab in the dark, but you may be able to use VT102 terminal codes to control the cursor without having to use Curses. The relevant VT102 commands that you'd be interested in all consist of sending ESC, then [, then the specific command parameters.
For instance, to move the cursor up one line, one needs to output:
ESC [ 1 A
0x1B 0x5B 0x31 0x41
Be warned that the VT102 documentation generally uses octal, so keep an ascii table handy if you're using hex.
All of this advice is given without having tested it -- I don't know if VT102 commands can be embedded into your bash prompt, but I thought it might be worth a shot.
Edit: Yeah -- looks like a lot of people use VT102 formatting codes in their bash prompts. To translate my above example into something Bash would recognize, putting:
\e[1A
into your prompt should move the cursor up one line.
This is very possible. If your bash has C-v set as the readline quoted-insert command, you can simply add the following to your ~/.inputrc:
RETURN: "\C-e\C-v\n\C-v\n\n"
This wil make bash (readline, actually) insert two verbatim newlines before a regular interpreted newline. By default, only one is inserted, which is what causes output to start on the line after the prompt.
You can test if C-v is set to quoted-insert by typing it in bash (that's Ctrl+V) followed by e.g. an up arrow. This should print ^[[A or something similar. If it doesn't, you can bind it in ~/.inputrc too:
C-v: quoted-insert
RETURN: "\C-e\C-v\n\C-v\n\n"
~/.inputrc can be created if it doesn't exist. The changes will not take effect in running bashes unless you issue a readline re-read-init-file command (by default on C-x C-r). Be careful though. If you do something wrong, enter will no longer issue commands, and fixing your mistake could prove to be difficult. If you should do something wrong, C-o will by default also accept the line.
Adding a newline followed by moving the cursor back to the regular prompt (like you described) is possible, but will not have the effect you intend. The newline you inserted would simply be overwritten by the application output, since you moved the cursor back in front of it.
This works:
trap echo DEBUG
It doesn't add an extra newline if you hit return at an empty prompt.
The command above will cause a newline to be output for every member of a pipeline or multi-command line such as:
$ echo foo; echo bar
\n
foo
\n
bar
To prevent that so that only one extra newline is output before all command output:
PROMPT_COMMAND='_nl=true'; trap -- '$_nl && [[ $BASH_COMMAND != $PROMPT_COMMAND ]] && echo; _nl=false' DEBUG
The DEBUG trap is performed before each command so before the first command it checks to see if the flag is true and, if so, outputs a newline. Then it sets the flag to false so each command afterwards on the line doesn't trigger an extra newline.
The contents of $PROMPT_COMMAND are executed before the prompt is output so the flag is set to true - ready for the next cycle.
Because pressing enter on an empty command line still triggers the execution of the contents of $PROMPT_COMMAND the test in the trap also checks for those contents as the current command and doesn't perform the echo if they match.
I believe (but haven't tried) if you put '\n\b' in the prompt string it would do that.
In general, if you want to find out the codes to do anything a terminal can do, read the terminfo man page.
In this case, the cursor up one line code can be determined by:
tput cuu1
If you redirect the tput output to a file, you can see what control characters are used.
Bash also supports the PROMPT_COMMAND variable, allowing you to run arbitrary commands before each prompt is issued.