Environment Variables

The absolute path of the directory containing the Julia executable, which sets the global variable Sys.BINDIR. If $JULIA_BINDIR is not set, then Julia determines the value Sys.BINDIR at run-time.

The executable itself is one of

by default.

The global variable Base.DATAROOTDIR determines a relative path from Sys.BINDIR to the data directory associated with Julia. Then the path

determines the directory in which Julia initially searches for source files (via Base.find_source_file()).

Likewise, the global variable Base.SYSCONFDIR determines a relative path to the configuration file directory. Then Julia searches for a startup.jl file at

by default (via Base.load_julia_startup()).

For example, a Linux installation with a Julia executable located at /bin/julia, a DATAROOTDIR of ../share, and a SYSCONFDIR of ../etc will have JULIA_BINDIR set to /bin, a source-file search path of

and a global configuration search path of

A directory path that indicates which project should be the initial active project. Setting this environment variable has the same effect as specifying the --project start-up option, but --project has higher precedence. If the variable is set to @. then Julia tries to find a project directory that contains Project.toml or JuliaProject.toml file from the current directory and its parents. See also the chapter on Code Loading.

The JULIA_LOAD_PATH environment variable is used to populate the global Julia LOAD_PATH variable, which determines which packages can be loaded via import and using (see Code Loading).

Unlike the shell PATH variable, empty entries in JULIA_LOAD_PATH are expanded to the default value of LOAD_PATH, ["@", "@v#.#", "@stdlib"] when populating LOAD_PATH. This allows easy appending, prepending, etc. of the load path value in shell scripts regardless of whether JULIA_LOAD_PATH is already set or not. For example, to prepend the directory /foo/bar to LOAD_PATH just do

If the JULIA_LOAD_PATH environment variable is already set, its old value will be prepended with /foo/bar. On the other hand, if JULIA_LOAD_PATH is not set, then it will be set to /foo/bar: which will expand to a LOAD_PATH value of ["/foo/bar", "@", "@v#.#", "@stdlib"]. If JULIA_LOAD_PATH is set to the empty string, it expands to an empty LOAD_PATH array. In other words, the empty string is interpreted as a zero-element array, not a one-element array of the empty string. This behavior was chosen so that it would be possible to set an empty load path via the environment variable. If you want the default load path, either unset the environment variable or if it must have a value, set it to the string :.

The JULIA_DEPOT_PATH environment variable is used to populate the global Julia DEPOT_PATH variable, which controls where the package manager, as well as Julia’s code loading mechanisms, look for package registries, installed packages, named environments, repo clones, cached compiled package images, configuration files, and the default location of the REPL’s history file.

Unlike the shell PATH variable but similar to JULIA_LOAD_PATH, empty entries in JULIA_DEPOT_PATH are expanded to the default value of DEPOT_PATH. This allows easy appending, prepending, etc. of the depot path value in shell scripts regardless of whether JULIA_DEPOT_PATH is already set or not. For example, to prepend the directory /foo/bar to DEPOT_PATH just do

If the JULIA_DEPOT_PATH environment variable is already set, its old value will be prepended with /foo/bar. On the other hand, if JULIA_DEPOT_PATH is not set, then it will be set to /foo/bar: which will have the effect of prepending /foo/bar to the default depot path. If JULIA_DEPOT_PATH is set to the empty string, it expands to an empty DEPOT_PATH array. In other words, the empty string is interpreted as a zero-element array, not a one-element array of the empty string. This behavior was chosen so that it would be possible to set an empty depot path via the environment variable. If you want the default depot path, either unset the environment variable or if it must have a value, set it to the string :.

The absolute path REPL.find_hist_file() of the REPL’s history file. If $JULIA_HISTORY is not set, then REPL.find_hist_file() defaults to

Sets the maximum number of different instances of a single package that are to be stored in the precompile cache (default = 10).

If set to true, linker commands will be displayed during precompilation.

If set to true, this indicates to the package server that any package operations are part of a continuous integration (CI) system for the purposes of gathering package usage statistics.

The number of parallel tasks to use when precompiling packages. See Pkg.precompile.

The default directory used by Pkg.develop for downloading packages.

If set to 1, this will ignore incorrect hashes in artifacts. This should be used carefully, as it disables verification of downloads, but can resolve issues when moving files across different types of file systems. See Pkg.jl issue #2317 for more details.

If set to true, this will enable offline mode: see Pkg.offline.

If set to 0, this will disable automatic precompilation by package actions which change the manifest. See Pkg.precompile.

Specifies the URL of the package registry to use. By default, Pkg uses https://pkg.julialang.org to fetch Julia packages. In addition, you can disable the use of the PkgServer protocol, and instead access the packages directly from their hosts (GitHub, GitLab, etc.) by setting: export JULIA_PKG_SERVER=""

Specifies the preferred registry flavor. Currently supported values are conservative (the default), which will only publish resources that have been processed by the storage server (and thereby have a higher probability of being available from the PkgServers), whereas eager will publish registries whose resources have not necessarily been processed by the storage servers. Users behind restrictive firewalls that do not allow downloading from arbitrary servers should not use the eager flavor.

If set to true, this will unpack the registry instead of storing it as a compressed tarball.

If set to true, Pkg operations which use the git protocol will use an external git executable instead of the default libgit2 library.

The accuracy of the package resolver. This should be a positive integer, the default is 1.

Specify hosts whose identity should or should not be verified for specific transport layers. See NetworkOptions.verify_host

Specify the file or directory containing the certificate authority roots. See NetworkOptions.ca_roots

The absolute path of the shell with which Julia should execute external commands (via Base.repl_cmd()). Defaults to the environment variable $SHELL, and falls back to /bin/sh if $SHELL is unset.

The editor returned by InteractiveUtils.editor() and used in, e.g., InteractiveUtils.edit, referring to the command of the preferred editor, for instance vim.

$JULIA_EDITOR takes precedence over $VISUAL, which in turn takes precedence over $EDITOR. If none of these environment variables is set, then the editor is taken to be open on Windows and OS X, or /etc/alternatives/editor if it exists, or emacs otherwise.

To use Visual Studio Code on Windows, set $JULIA_EDITOR to code.cmd.

Overrides the global variable Base.Sys.CPU_THREADS, the number of logical CPU cores available.

A Float64 that sets the value of Distributed.worker_timeout() (default: 60.0). This function gives the number of seconds a worker process will wait for a master process to establish a connection before dying.

An unsigned 64-bit integer (uint64_t) that sets the maximum number of threads available to Julia. If $JULIA_NUM_THREADS is not positive or is not set, or if the number of CPU threads cannot be determined through system calls, then the number of threads is set to 1.

If $JULIA_NUM_THREADS is set to auto, then the number of threads will be set to the number of CPU threads.

If set to a string that starts with the case-insensitive substring "infinite", then spinning threads never sleep. Otherwise, $JULIA_THREAD_SLEEP_THRESHOLD is interpreted as an unsigned 64-bit integer (uint64_t) and gives, in nanoseconds, the amount of time after which spinning threads should sleep.

If set to anything besides 0, then Julia’s thread policy is consistent with running on a dedicated machine: the master thread is on proc 0, and threads are affinitized. Otherwise, Julia lets the operating system handle thread policy.

The formatting Base.error_color() (default: light red, "\033[91m") that errors should have at the terminal.

The formatting Base.warn_color() (default: yellow, "\033[93m") that warnings should have at the terminal.

The formatting Base.info_color() (default: cyan, "\033[36m") that info should have at the terminal.

The formatting Base.input_color() (default: normal, "\033[0m") that input should have at the terminal.

The formatting Base.answer_color() (default: normal, "\033[0m") that output should have at the terminal.

Enable debug logging for a file or module, see Logging for more information.

If set, these environment variables take strings that optionally start with the character 'r', followed by a string interpolation of a colon-separated list of three signed 64-bit integers (int64_t). This triple of integers a:b:c represents the arithmetic sequence a, a + b, a + 2*b, …​ c.

If the value of the environment variable begins with the character 'r', then the interval between garbage collection events is randomized.

If set to anything besides 0, then the Julia garbage collector never performs "quick sweeps" of memory.

If set to anything besides 0, then the Julia garbage collector will wait for a debugger to attach instead of aborting whenever there’s a critical error.

If set to anything besides 0, then the compiler will create and register an event listener for just-in-time (JIT) profiling.

If set to anything besides 0 enables GDB registration of Julia code on release builds. On debug builds of Julia this is always enabled. Recommended to use with -g 2.

Arguments to be passed to the LLVM backend.