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exec-path-from-shell
A GNU Emacs library to ensure environment variables inside Emacs look the same as in the user's shell.
Motivation
Ever find that a command works in your shell, but not in Emacs?
This happens a lot on OS X, where an Emacs instance launched as a GUI app inherits a
default minimal set of environment variables that are probably not the ones you see
in a terminal window. Similarly, if you start Emacs as a daemon from systemd
or launchd
,
it will run with a default set of environment variables.
This library solves this problem by copying important environment variables from the user's shell: it works by asking your shell to print out the variables of interest, then copying them into the Emacs environment.
Compatibility
Supported shells:
zsh
bash
tcsh
fish
nu
Note that shell variables which have not been exported as environment
variables (e.g. using the "export" keyword) may not be visible to
exec-path-from-shell
.
If you experience issues, enable the variable
exec-path-from-shell-debug
before runnin functions from the package:
this will produce detailed logging in *Messages*
about the shell
command line and output.
Installation
Installable packages are available via MELPA: do
M-x package-install RET exec-path-from-shell RET
.
Alternatively, download
the latest release or clone the repository, and install
exec-path-from-shell.el
with M-x package-install-file
.
Usage
Add the following to your init.el
(after calling package-initialize
):
(when (memq window-system '(mac ns x))
(exec-path-from-shell-initialize))
This sets $MANPATH
, $PATH
and exec-path
from your shell, but only
when executed in a GUI frame on OS X and Linux.
If you launch Emacs as a daemon from systemd
or similar, you
might like to use the following snippet:
(when (daemonp)
(exec-path-from-shell-initialize))
You can copy values of other environment variables by customizing
exec-path-from-shell-variables
before invoking
exec-path-from-shell-initialize
, or by calling
exec-path-from-shell-copy-env
, e.g.:
(exec-path-from-shell-copy-env "PYTHONPATH")
This function may also be called interactively.
The author uses the following configuration snippet before calling exec-path-from-shell-initialize
:
(require 'exec-path-from-shell)
(dolist (var '("SSH_AUTH_SOCK" "SSH_AGENT_PID" "GPG_AGENT_INFO" "LANG" "LC_CTYPE" "NIX_SSL_CERT_FILE" "NIX_PATH"))
(add-to-list 'exec-path-from-shell-variables var))
Setting up your shell startup files correctly
Note that your shell will inherit Emacs's environment variables when
it is run by exec-path-from-shell
-- to avoid surprises your config
files should therefore set the environment variables to their exact
desired final values, i.e. don't do this:
export PATH=/usr/local/bin:$PATH
but instead do this:
export PATH=/usr/local/bin:/usr/bin:/bin
To be safe, exec-path-from-shell
starts an interactive (and login)
shell by default, but this can be much slower than necessary.
Interactive shells often have fancy features enabled that are only
helpful when one interacts directly with the shell, and this can
frequently cause startup time to exceed 750ms. This can be avoided:
- Follow best practice by setting your environment variables so that
they are available to both interactive and non-interactive shells.
In practical terms, for most people this means setting them in
~/.profile
,~/.bash_profile
,~/.zshenv
instead of~/.bashrc
and~/.zshrc
. - Once a non-interactive shell sets your environment variables
correctly, adjust
exec-path-from-shell-arguments
appropriately (often tonil
) before callingexec-path-from-shell-initialize
so that it will start a non-interactive shell.
To learn more about how popular shells load start-up files, read this helpful article.
Making exec-path-from-shell
faster
If evaluation takes more than
exec-path-from-shell-warn-duration-millis
(500ms by default) then
exec-path-from-shell
will print a warning.
- Non-interactive shells start up faster. Follow the steps in the
section above so that you can run your shell without
-i
and still get the right environment variable settings. When"-i"
is then removed fromexec-path-from-shell-arguments
, this package becomes more efficient. - Invoking the shell has a non-trivial overhead in any case. Don't
call
exec-path-from-shell-copy-env
repeatedly, since each invocation starts a shell. Instead, setexec-path-from-shell-variables
to the full list of vars you want, and callexec-path-from-shell-initialize
once.
Further help
C-h f exec-path-from-shell-initialize
C-h f exec-path-from-shell-copy-env
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