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NAME

flox-activate - activate environments

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SYNOPSIS

flox [<general-options>] activate
     [-d=<path> | -r=<owner>/<name>]
     [-t]
     [--print-script]
     [--start-services | --no-start-services]
     [-m=(dev|run)]
     [-g=<generation>]
     [-c=<shell command> | -- <exec command>...]

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DESCRIPTION

Configures a shell with everything defined by the environment:
  • Downloads packages and adds their bin directories to your $PATH.
  • Sets environment variables and aliases.
  • Runs hooks.
  • Starts services (if --start-services is specified).
flox activate may run in one of four modes:
  • interactive: flox activate when invoked from an interactive shell
    Launches an interactive sub-shell. The shell to be launched is determined by $FLOX_SHELL or $SHELL.
  • shell command: flox activate -c CMD
    Runs CMD in the same environment as if run inside an interactive shell produced by an interactive flox activate. The shell CMD is run by is determined by $FLOX_SHELL or $SHELL. Because CMD is passed to a shell, shell features like running multiple commands with && can be used.
  • exec command: flox activate -- CMD
    Execs CMD directly after performing all parts of activation except for running scripts in [profile].
  • in-place: flox activate when invoked from a non-interactive shell with its stdout redirected e.g. eval "$(flox activate)"
    Produces commands to be sourced by the parent shell. Flox will determine the parent shell from $FLOX_SHELL or otherwise automatically determine the parent shell and fall back to $SHELL.
flox activate currently supports bash, fish, tcsh, and zsh shells for any of the detection mechanisms described above. When invoked interactively, the shell prompt will be modified to display the active environments, as shown below: 
flox [env1 env2 env3] <normal prompt>
When multiple environments are activated each of their shell hooks (profile and hook scripts) are executed in the context of the environment that they come from. This means that for each shell hook various environment variables such as PATH, MANPATH, PKG_CONFIG_PATH, PYTHONPATH, etc, are set to the appropriate values for the environment in which the shell hook was defined. See manifest.toml for more details on shell hooks. To reverse activation, run flox-deactivate. Inside a flox activate subshell, flox deactivate is equivalent to exit.

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AUTO-ACTIVATION

Experimental: Auto-activation is experimental and behind a feature flag, and its behavior is subject to change. Enable it by setting FLOX_FEATURES_AUTO_ACTIVATE=true in your environment, or by running flox config --set features.auto_activate true. See the AUTO-ACTIVATION section of flox-activate(1) for details.
Auto-activation activates an environment automatically when you enter a directory that contains it, and deactivates it when you leave, so you do not have to run flox activate or flox deactivate by hand.

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Enabling auto-activation

Two things are required:
  1. The Flox prompt hook must be installed in your shell. The hook is installed by any in-place activation, so add a line such as eval "$(flox activate -D)" to your shell’s startup file (for example ~/.bashrc, ~/.zshrc, ~/.config/fish/config.fish, or ~/.tcshrc). If you already activate a default or other environment in-place at startup, the hook is already installed. The hook ships with Flox and stays dormant until the feature flag below is set. Run flox config --set disable_hook true to opt out of the hook entirely.
  2. The auto_activate feature flag must be enabled, either with FLOX_FEATURES_AUTO_ACTIVATE=true in your environment or with flox config --set features.auto_activate true.

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How it works

On each prompt the hook looks for .flox environments at or above the current directory. An environment is auto-activated only if you have allowed it. Allowed environments are activated outermost-first; when you leave their directory they are deactivated again. Services are not started unless auto-start = true is set in the manifest’s [services] section.

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Allowing and denying environments

The first time you enter a directory with an environment that you have neither allowed nor denied, and auto_activate is set to prompt (the default), Flox asks before activating it: 
Auto-activate the environment in '/path/to/project'? [y/N]
Answering y allows the environment and activates it immediately, and records the choice so you are not asked again. Answering N (or pressing Enter) skips the environment for the current shell session only; you are asked again in a new shell or when you re-enter the directory. To stop being asked for this directory, run flox-activate-deny: 
flox activate deny
Set the auto_activate config option to allowed to skip the prompt entirely and auto-activate only environments you have already allowed. Manage these decisions ahead of time with the flox-activate-allow and flox-activate-deny subcommands. Decisions are stored in the user config file under auto_activate_environments. See flox-config for the auto_activate, auto_activate_environments, auto_activate_fish_mode, and disable_hook options.

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OPTIONS

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Activate Options

-c <command>, --command <command>
Shell command string to run in a subshell started in the activated environment -- <command> [<arguments>]
Command to exec in the activated environment. This does not run any profile scripts -t, --trust
Trust a remote environment for this activation. Activating an environment executes a shell hook which may execute arbitrary code. This presents a security risk, so you will be prompted whether to trust the environment. Environments owned by the current user and Flox are always trusted. You may set certain environments to always be trusted using the config key trusted_environments."<owner/name>" = (trust | deny), or via the following command: flox config --set trusted_environments.\"<owner/name>\" trust. --print-script
Prints an activation script to stdout that’s suitable for sourcing in a shell rather than activation via creating a subshell. flox automatically knows when to print the activation script to stdout, so this command is just a debugging aid for users. -s, --start-services
Start the services listed in the manifest when activating the environment. If no services are running, the services from the manifest will be started, otherwise a warning will be displayed and activation will continue. To start services by default without requiring -s, set services.auto-start = true in the manifest. The services started with this flag will be cleaned up once the last activation of this environment terminates. A remote environment can only have a single set of running services, regardless of how many times the environment is activated concurrently. --no-start-services
Don’t start services even if configured in the manifest with auto-start = true. -m (dev|run), --mode (dev|run)
Activate the environment in either “dev” or “run” mode. Overrides the options.activate.mode setting in the manifest. See manifest.toml for more details on activation modes. -g <generation>, --generation <generation>
Activate a FloxHub environment at a specific generation.

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Environment Options

If no environment is specified for an environment command, the environment in the current directory or the active environment that was last activated is used. -d, --dir
Path containing a .flox/ directory. -r, --reference
A FloxHub environment, specified in the form <owner>/<name>. -D, --default
Use your default environment (<your-user>/default). When unauthenticated in an interactive context, you will be prompted to log in. In non-interactive contexts (e.g., scripts or CI), this flag will fail with an error when authentication is missing.

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General Options

-h, --help
Prints help information. The following options can be passed when running any flox subcommand but must be specified before the subcommand. -v, --verbose
Increase logging verbosity. Invoke multiple times for increasing detail. -q, --quiet
Silence logs except for errors.

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ENVIRONMENT VARIABLES

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Variables set by flox activate

$FLOX_ENV
Contains the path to the built environment. This directory contains a merged set of bin, lib, etc directories for all the packages in the environment. $FLOX_PROMPT_ENVIRONMENTS
Contains a space-delimited list of the active environments, e.g. owner1/foo owner2/bar local_env. If hide_default_prompt is set to true, environments named default are excluded. $FLOX_ENV_CACHE
activate sets this variable to a directory that can be used by an environment’s hook to store transient files. These files will persist for environments used locally, but they will not be pushed, and they will not persist when using a remote environment with -r. $FLOX_ENV_PROJECT
activate sets this variable to the directory of the project using the Flox environment. For environments stored locally, this is the directory containing the environment. When running flox activate -r, this is set to the current working directory. This variable can be used to find project files in environment hooks. $FLOX_ENV_DESCRIPTION
activate sets this variable to the project name of the environment. It can be used to identify or construct messages about the environment. $_FLOX_ACTIVE_ENVIRONMENTS
A JSON array containing one object per active environment. This is currently an implementation detail and its contents are subject to change. $FLOX_ACTIVATE_START_SERVICES
"true" if this activation started services, "false" otherwise.

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Variables used by flox activate

$FLOX_SHELL, $SHELL
When activating an environment Flox will either launch a sub-shell or emit commands to configure an already-running (parent) shell. In both of these cases Flox needs to know which shell to use, and these variables are used to control the selection process.
  • interactive and command modes: When launching a sub-shell Flox will invoke the shell specified in $FLOX_SHELL if set or fall back to invoke $SHELL by default.
  • in-place mode: When performing an “in place” activation Flox will attempt to detect its parent shell type unless overridden by the $FLOX_SHELL variable, and if it cannot detect its parent shell type then will produce a script with syntax determined by $SHELL.
$FLOX_PROMPT_COLOR_{1,2}
Flox adds text to the beginning of the shell prompt to indicate which environments are active. A set of default colors are used to color this prompt, but the colors may be overridden with the $FLOX_PROMPT_COLOR_1 and $FLOX_PROMPT_COLOR_2 environment variables. The values of these variables should be integers chosen from the 256-color palette as described in the xterm-256color chart.

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EXAMPLES

Activate an environment stored in the current directory: 
flox activate
Activate an environment some_user/myenv that’s been pushed to FloxHub: 
flox activate -r some_user/myenv
Invoke a command inside an environment without entering its subshell: 
flox activate -- cmd --some-arg arg1 arg2
Activate default Flox environment only within the current shell (add to the relevant “rc” file, e.g. ~/.bashrc or ~/.zprofile): 
eval "$(flox activate)"

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SEE ALSO

flox-deactivate, flox-push, flox-pull, flox-edit, flox-delete