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Questions tagged [subprocess]

52 questions
15
votes
2 answers

How to prevent slow-down when an inferior processes generates long lines?

I use Emacs with Geiser to hack on some Scheme code. As I'm playing around in the REPL I sometimes evaluate expressions that result in a lot of output, often all on one line. For example, I just played with SRFI-41 (streams) and created a character…
user2005
13
votes
1 answer

Asynchronously wait for output from a comint process

First of all, a disclaimer. I have researched this many times, and I am pretty sure that I have already found the answer one way or another, but I just don't understand it. My problem is the following: I have a process running through comint I want…
T. Verron
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10
votes
1 answer

How do I prevent one subprocess from starving others?

To be clear, I'm not talking about anything that should require emacs to be multithreaded (though that would probably also solve this). To reproduce: emacs -Q # I'm running 24.4.1 Make a second frame Switch back to first frame M-x shell M-x…
Joseph Garvin
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10
votes
2 answers

Run ssh-add from Emacs and enter a passphrase

I want to call the ssh-add shell command. So I invoke M-x shell-command RET, and in the minibuffer, I type: ssh-add .ssh/id_rsa The only thing I get is: ssh_askpass: exec(/usr/bin/ssh-askpass): No such file or directory^M How can I make Emacs give…
Nsukami _
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9
votes
1 answer

Process input seems buggy in Emacs on OS X

I have a process that I'm trying to send input to on OS X. I'm using Emacs' builtin functions for doing this: process-send-string and process-send-region. However, it seems that there are issues when doing this on OS X. Specifically, it seems that I…
GDP2
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9
votes
3 answers

Persistent environment for M-x compile

When I run M-x compile it spawns a new subshell to execute my compile command. As soon as the compile command returns, the shell process is killed. I can see why this would be desirable in most cases, but I am currently in a situation where it is…
nispio
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8
votes
3 answers

Set environment variables for spawned subprocesses

I would like to set the environment variables for a spawned subprocess only. They are controlled by process-environment. The documentation says: binding that variable with let is also reasonable practice. In this example I try to unset HOME…
antonio
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8
votes
1 answer

Read process output line by line

If there a way to read the output of a subprocess line by line, or at least to get it in small batches? I have a subprocess doing work in the background, and printing a line every time it completes a task. There are many such small tasks, so I…
Clément
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6
votes
2 answers

Temporarily set the `default-directory` for `start-process`

Is it possible to set the default-directory temporarily (e.g., let-bound) when using start-process? If so, how please. (let ((default-directory "/Users/HOME/Desktop/tmp")) (start-process "touch-file" nil "touch" "test.txt")) start-process…
lawlist
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5
votes
1 answer

How to run a custom formatting tool on save?

While there are packages that format on save, I'd like to be able to run a custom command that auto-formats a file on save. Upon saving it runs an external process that: Takes the buffer as stdin. Outputs to a temporary file. After that: The…
ideasman42
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5
votes
1 answer

Asynchronous version of shell-command-on-region?

I have a problem which is very similar to this one. I have some text that I'd like to listen to with macOS's say utility. Unfortunately, Emacs locks up when I use shell-command-on-region because it is not asynchronous. In other words, Emacs waits…
GDP2
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5
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1 answer

How to attach/connect two subprocesses?

The general case: Simply put, given that I start two processes (Aand B) with, e.g., async-start-process, what is best way of killing B if A terminates? My specific usecase: I'm debugging embedded software on an external chip and launch a GDB server…
thomsten
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5
votes
1 answer

Capturing stderr of subprocesses

I'm trying to capture stderr separately from stdout for a (synchronous) process run from emacs. I've found one way of doing it based on some code copied from emacs' shell-command function (I don't want to use shell-command directly because there is…
dshepherd
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4
votes
2 answers

What is the syntax for a subshell in eshell?

How to write the analogue of a bash-command like: (cd ../repo && git fast-export master) | darcs convert import repo_master in eshell? Here a subshell is employed to restrict the effect of cd.
imz -- Ivan Zakharyaschev
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4
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1 answer

How to partially block user input while Emacs subprocess is running

I have a custom function that updates the etags file before prompting the user to input a desired tag to be located. Although I am pretty good about setting the current buffer to read-only before going about other activities, sometimes I forget and…
lawlist
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