How to switch from shell buffer to another - emacs

I learn to use emacs. When I enter M-x shell , I enter the shell mode, but I don't know how to exit shell mode. I want to be back to fundamental mode to continue to my editing work. I search this question Emacs switching out of terminal, but when I press C-c o , the input will be treated as a command, so how to exit ?

The shell will be running in a buffer. You can switch back to the buffer where you were doing your work using C-x b.

You can try shell-toggle.el for quick jump back and forth between your current buffer and a shell buffer.
You can also try my hacked version of shell-toggle, which let you open a shell in the path of your current buffer (file). See the following link:
http://zhangda.wordpress.com/2009/04/08/my-hack-on-shell-toggle/

Related

Emacs execute process continuously

There's a way to launch a process(continuously) in emacs?
For example, imagine ruby REPL, I expect launch the command "irb" in emacs and it should be in some some kinda of separated tab or buffer.
For the specific case of REPLs in Spacemacs you can start one for any supported language with SPC m s i then explore SPC m s prefix command for all the commands to interact with the REPL.
M-x shell
irb
This will cover simple use cases. To get previous commands, type M-p and M-n instead of up and down.
You can get a fancier version from #legoscia's link.
Can also do M-! to execute a single shell command and output to a new buffer.

Running python interpreter or language X in Emacs

Every time I start the interpreter for a programming language (lets consider python in this case) emacs opens the interpreter in the window which is not current. Note that I have two windows open, so the interpreter is always opening in the opposite window that I am currently in. This is annoying because then I always have to switch windows after I open an interpreter...
How can I get the python interpreter to open in the current window inside emacs?
Can I solve this problem generally for other programs/shells/buffers that do not open in the current window?
I note that this also happens frequently with other emacs commands (such as C-h v and the description of the variable opens in the window that is not current)
All help is greatly appreciated!
Interpreter-buffers connect with a process. If not already there, it must be a different one than the buffer called from - otherwise the current buffers contents is lost.
You might be interested in org-mode, org-babel, which provides a way to insert results in current buffer when executing source-code.
With python-mode.el, set py-switch-buffers-on-execute-p to non-nil. After M-x py-shell, cursor is in new shell.
If py-split-windows-on-execute-p is nil, M-x py-shell should switch to Python shell without splitting the window. See more options if re-using an existing py-shell etc.
With python.el, M-x run-python switches into the Python-shell.
See also customizable variable pop-up-windows.

Perl debugger on Emacs: Clear screen (buffer)?

Say I have long debugging session in Perl with perldb on Emacs (M-x perldb). The output piles up, and at some point it becomes difficult to navigate through it.
I can restart the debugger with R, but that doesn't clear up the previous output. Is there a command to clear up the output of the buffer of the Perl debugger without having to kill the debugger and starting a new session?
You can run comint-truncate-buffer. This will remove all but the last 1024 lines from the buffer. The size can be customized by changing comint-buffer-maximum-size.
If you'd like to have the buffer truncated automatically, run this snippet of elisp:
(add-hook 'comint-output-filter-functions 'comint-truncate-buffer)
Debugger input and output is buffer contents like any other — if you want to delete it, just do it. For example, C-x h C-w (mark-whole-buffer followed by kill-region) works in perldb buffers just fine, and is the closest equivalent to a "clear screen" command in a text terminal.

How can I keep my putty scrollback buffer when using emacs -nw and gnu screen?

Here's my problem - hopefully I can explain this well enough:
I use Putty on Windows, and then start a gnu screen session. I may run several shell commands in putty, and then in the same screen, run emacs -nw. The problem is that when I exit emacs, the scrollback buffer (in putty) is messed up. What was on the screen when I started emacs is gone, and if I scroll upward I see various artifacts of screen (e.g. the screen "bar" at the bottom, etc.).
If I don't use screen and just open emacs -nw directly from putty, all my history is still there in the buffer when I exit emacs.
Likewise, if I do use screen, and use vi within a screen instead of emacs, when I exit vi, everything is there.
Is this just some weird interaction with putty and emacs? Is there a way to fix it?
Have you tried setting scrollback buffer size to something else than default? scrollback
In .screenrc put this line:
defscrollback 10000
Here's my config .screenrc. Tried to reproduce this problem but no luck... you can try if it fixes for you:
termcapinfo xterm* ti#:te#
startup_message off
vbell off
autodetach on
altscreen on
shelltitle "$ |bash"
defscrollback 10000
defutf8 on
nonblock on
hardstatus alwayslastline
hardstatus string '%{= kw}[ %{= kb}%H%{= kw} ][%= %{= kw}%?%-Lw%?%{= kW}%n*%f %t%?%?%{= kw}%?%+Lw%?%?%= ][ %{r}%l%{w} ]%{w}[%{r} %d/%m/%y %C %A %{w}]%{w}'
bind 'q' quit
Just at the end I would as well suggest you getting familiar with tmux -> http://tmux.sourceforge.net/
BTW. hopefully you're using newest version of PuTTy right? :) - > http://puttytray.goeswhere.com/
This sounds like Emacs and Screen are stepping on each others toes over the alternate screen feature of your terminal.
I cannot reproduce this issue, but maybe putting the following in your ~/.screenrc would help:
altscreen on
Have you considered using tmux as an alternative to GNU screen?

Would it be possible to jump between prev/next Terminal command prompts?

I'm using zsh in OS X Terminal.app and for quite a while, I've been longing for a way to jump back and forth between prev/next prompts in the terminal's output.
One convenience with this would be to be able to review (and track errors at) the end of each command's output; eg. when you building stuff from source with ./configure; make; make install. Note: I'm obviously not referring to jumping back and forth in the command-history, but for a way to take a peek at the endings of each command's output.
Has anyone heard of such functionality in the *nix (preferrably also Mac) world? Would it require some sort of OS-centric Terminal plugin, or can it be programmatically done via a shell script which can be tied to a keyboard shortcut? Maybe I'm the only one thinking about this? :)
Edit: Here's an example scenario: Let's say I want to compile and install some program (using standard ./configure && make && make install procedure) and after the make command, I run into some errors. Now, the way I understand it (I may be completely wrong), the crucial error causing the make command to fail usually shows up in the last line(s) in the output, no? Anyway, at this point, I might do something like cat INSTALL to read up on the INSTALL document to check whether there's something I've missed. NOW, if I want to go back to see what the error was, that caused my initial make command to fail, I then have to manually scroll up to that position again, since my cat INSTALL command printed a ton of text after it.
I don't know if this scenario is the most elucidative – but there are many other situations where I wish I could just "jump" back to previous prompt lines and check up on previous command output; whether it was a simple ls command, make, git status, or whatever it was – swapping positions in the window by means of using prompt lines as "bookmark" positions seems an interesting idea to me.
command + left or right goes between tabs in iterm. is this what you are asking?
Emacs has a shell-mode that runs a shell inside the Emacs editor, providing a rich environment of additional commands for navigating and working with shell commands. This includes commands for going to the previous/next prompt, and deleting the output from commands so you can "clean up" and issue another command.
If you aren't familiar with Emacs: to start a shell inside Emacs, run emacs from the shell, then type Esc-x (or Meta-x, if you have "Use option as meta key" enabled in Terminal > Preferences > Settings > [profile] > Keyboard). This will ask for a command to execute. Enter shell.
To see a list of commands you can use in Shell Mode, enter Control-h m. Here are the ones for moving the cursor to the previous/next prompt:
C-c C-n comint-next-prompt
C-c C-p comint-previous-prompt
These commands would also be useful:
C-c C-r comint-show-output
C-c C-o comint-delete-output