How do I map a certain input in bash to a command? - bash

So I was wondering if it is possible for me to map a certain input to a command in gnome terminal. For example, when I type "foo" in the command shell, it would automatically execute a certain command like going to a directory where a program is located and execute that program in a specific configuration.

Yes, it is called an alias:
A Bash alias is essentially nothing more than a keyboard shortcut, an
abbreviation, a means of avoiding typing a long command sequence. If,
for example, we include alias lm="ls -l | more" in the ~/.bashrc file,
then each lm [1] typed at the command-line will automatically be
replaced by a ls -l | more. This can save a great deal of typing at
the command-line and avoid having to remember complex combinations of
commands and options. Setting alias rm="rm -i" (interactive mode
delete) may save a good deal of grief, since it can prevent
inadvertently deleting important files.
So basically:
alias foo="cd /path/to/dir; ./myprogram; cd -"
cd - is following #Cyrus's suggestion - to return you to the directory you started from. This is safer and more expected of most commands, but of course, you can use whatever you like.

Related

How do I edit current shell command without executing it?

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

How can I make shell autocomplete the beginning of a filepath?

I have a project with a deeply nested folder structure. Most of the time I know the name of the file I want to work with, but the folder path is too long/complicated to type when I want to edit it, like:
vim folder/is/deep/down/there/myfile.js
Is there a way to make the shell auto populate the path for me if the filename is unique, with something like:
vim *myfile.js
press TAB -->
vim folder/is/deep/down/there/myfile.js
I mostly use bash, but I'm fine with zsh if it can solve the problem.
I think this is what you're looking for, vim will open all instances of myfile.js in the directory. Fish shell will allow me to tab through the different matching files but I'm not sure it that works with bash.
vim **/myfile.js
What could be a good idea would be to use locate utility in a bash script.
Calling your bash script passing filename as argument would be a smart move, and then using the previously named utility to find it.
Having done that you could simply find if there was 1 or more matches, and if there's just a match you can just use vim [match].
And obviously, the script could be called like ./openinvim.sh myfile.js

How to execute a script in zsh and then become interactive?

I want to run a predetermined set of commands after the invocation of zsh (i.e. after .zshrc is executed) that returns the user to an interactive shell when complete.
Things like this comes to my mind:
urxvt -e 'zsh -c ". scriptname"'
but instead of exiting zsh and the terminal once the script finishes, I want an interactive shell at the end. The idea is to simply save users from having to type ". scriptname" whenever they log in.
Application: Several users are using the same account (strange but true) and I want to help in adjusting user specific settings. Yes, I know that one could use different accounts for that :-)
Not really what you were asking for, but should have the desired result. You use an environment variable to pass the name of the user-specific script to source to .zshrc (or other appropriate startup file).
urxvt -e 'USERSCRIPT=scriptname zsh'
Then in .zshrc for the actual user, include
. $USERSCRIPT
(All of this is not to say that there isn't an option to run a command then remain in interactive mode; I just can't find a way to do it, so I offer this workaround.)

Bash alias autocompletion that considers only *.foo files

Whenever I want to start editing my LaTeX sources by launching, e.g., the command vim pdeOptAff.tex, I find that bash the (tab)-autocompletion is still tedious because the folder typically contains a bunch of files with the same name but different endings:
$ ls
pdaeOptAff.aux pdaeOptAff.out pdaeOptAff.tex.latexmain
pdaeOptAff.bbl pdaeOptAff.pdf pdaeOptAff.toc
pdaeOptAff.blg pdaeOptAff.synctex.gz
pdaeOptAff.log pdaeOptAff.tex
Since I always want to open the the ~.tex file, I would love to have a filter that makes autocomplete expand only the ~.tex files.
In addition, I have an alias defined: alias g='gvim --remote-silent'. So this filter, in particular, should work for the alias.
Try:
complete -f -X '!*.tex' g
Then, you can type:
g <TAB>
And get the completions. Note: this doesn't complete directories. Someone else may have a better solution using compgen.
There's a helpful autocomplete guide on The Linux Documentation Project too.

Can I use what I wrote on the shell (bash, cmd, irb, etc) in a script automatically?

The general idea is pretty simple, I want to make a script for a certain task, I do it in the shell (any shell), and then I want to copy the commands I have used.
If I copy all the stuff in the window, then I have a lot of stuff to delete and to correct. (and is not easy to copy from shell)
Resume: I want to take all the things I wrote...
Is there an easy way to do this easy task?
Update: Partial solution
In bash, the solution is pretty simple, there is a history command, and there are ports of the idea:
IRB: Tweaking IRB
Cmd: Use PowerShell -> Get-History (or use cygwin)
Another Update:
I found that doskey have a parameter history to do this:
cmd: Doskey /history >> history.cmd
Yes, you can use:
history -w filename.sh
This will save your command history to filename.sh. You may need to edit that to keep just the lines at the end that are part of your command sequence.
NOTE: This is a bash command and will not work with all shells.
script may help here. Typing script will throw you into a new shell and save
all input and output to a file called typescript. When you're done with your interaction,
exit the shell. The file typescript is then amenable to grep'ing. For example, you might
grep for your prompt and save the output to the file. If you're a clumsy typist like me, then you may need to do some cleanup work to remove backspaces. There used to be a program that did thisbut I don't seem to find it right now. Here is one I found on the
'net: http://www.cat.pdx.edu/tutors/files/fixts.cpp
This approach is especially useful if you want to track and post on the web an entire interactive session.

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