# Where to store .jl files

**URL:** <https://discourse.julialang.org/t/where-to-store-jl-files/101055>\
**Category:** New to Julia\
**Tags:** question\
**Created:** [July 1, 2023, 4:11pm UTC](https://discourse.julialang.org/t/where-to-store-jl-files/101055 "2023-07-01T16:11:21Z")\
**Posts on this page:** 12\
**Page:** 1

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**Author:** ![alan](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/alan/32/15970_2.png) [@alan](https://discourse.julialang.org/u/alan)\
**Post date:** [July 1, 2023, 4:11pm UTC](https://discourse.julialang.org/t/where-to-store-jl-files/101055/1 "2023-07-01T16:11:21Z")

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Julians seem to keep their .jl files under ~/.julia/dev. Why is this? Is this location used somehow by “import”, “using”, or “include”?

In C, I’m used to keeping source files under ~/src, then copying executables into ~/bin and libraries into ~/lib. Then I can use the executables and libraries from anywhere. In Julia, I have not yet discovered a similar system.

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**Author:** ![kellertuer](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/kellertuer/32/220707_2.png) [@kellertuer](https://discourse.julialang.org/u/kellertuer)\
**Post date:** [July 1, 2023, 4:18pm UTC](https://discourse.julialang.org/t/where-to-store-jl-files/101055/2 "2023-07-01T16:18:13Z")

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I have my source files either in a package, that is the package‘s `src/` folder or a specific repository/folder with example scripts (usually then either Pluto or Quarto notebooks).  
And I usually start (at least a local) package as soon as I want to share common code between notebooks. But the package would still be in my Julia Code default folder (`Repositories/Julia`).

> [@alan](#):
>
> Julians seem to keep their .jl files under ~/.julia/dev.

So could you maybe state where your assumption is from? I would feel strange storing generic stuff I use in a hidden folder.

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**Author:** ![lostella](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/lostella/32/356_2.png) [@lostella](https://discourse.julialang.org/u/lostella)\
**Post date:** [July 1, 2023, 6:07pm UTC](https://discourse.julialang.org/t/where-to-store-jl-files/101055/3 "2023-07-01T18:07:04Z")

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> [@alan](#):
>
> Julians seem to keep their .jl files under ~/.julia/dev

That’s where Pkg, the package manager, by default stores registered packages you `dev` (install for development).

[This section](https://docs.julialang.org/en/v1/manual/code-loading/) of the documentation explains how Julia code can be loaded, implying how one could go about organizing it. One generally wants to use environments, which are covered [here](https://docs.julialang.org/en/v1/manual/code-loading/#Environments). See also [the section](https://pkgdocs.julialang.org/v1/environments/) in Pkg’s documentation about managing environments.

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**Author:** ![goerz](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/goerz/32/3269_2.png) [@goerz](https://discourse.julialang.org/u/goerz)\
**Post date:** [July 1, 2023, 7:10pm UTC](https://discourse.julialang.org/t/where-to-store-jl-files/101055/4 "2023-07-01T19:10:52Z")

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`] dev name_of_package` always seemed like a bad feature to me.

If I want to dev-install something, I’ll manually clone its repository to `~/Documents/Programming` and the do `Pkg.develop(path="~/Documents/Programming/name_of_package")`. The `~/.julia` folder is best kept transient so that you can delete it without losing any important data.

I’m not sure if “keeping .jl files under `~/.julia/dev`” is all that common in the wider Julia community, but I’d certainly advise against it.

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<div class="post-metadata">

**Author:** ![kellertuer](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/kellertuer/32/220707_2.png) [@kellertuer](https://discourse.julialang.org/u/kellertuer)\
**Post date:** [July 1, 2023, 7:13pm UTC](https://discourse.julialang.org/t/where-to-store-jl-files/101055/5 "2023-07-01T19:13:26Z")

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When you start Julia in the base folder of your project `] dev .` is a nice shortcut to take a (locally checked out) package in development mode.

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**Author:** ![goerz](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/goerz/32/3269_2.png) [@goerz](https://discourse.julialang.org/u/goerz)\
**Post date:** [July 1, 2023, 7:24pm UTC](https://discourse.julialang.org/t/where-to-store-jl-files/101055/6 "2023-07-01T19:24:16Z")

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Sure, but that doesn’t put anything into `~/.julia/dev`, right? At least I think it’s equivalent to the more verbose `Pkg.develop(path=".")` which makes the current environment use the package implementation in the current working directory, and which I definitely use myself.

I’m not opposed to the shortcut `] dev path`, but `] dev name` for a package name that then gets cloned into `~/.julia/dev/` is not so great. Nor that `] dev something` is ambiguous whether `something` is a path or a name. That’s why, personally, I always use the explicit `Pkg.develop`, but it’s a separate gripe from whether or not to store code in `~/.julia/dev`.

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<div class="post-metadata">

**Author:** ![goerz](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/goerz/32/3269_2.png) [@goerz](https://discourse.julialang.org/u/goerz)\
**Post date:** [July 2, 2023, 4:29am UTC](https://discourse.julialang.org/t/where-to-store-jl-files/101055/7 "2023-07-02T04:29:05Z")

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Actually, there is one use case where dev-installing into `~/.julia/dev` can be very useful: debugging. If there’s something weird going on in some random package that I’m not the developer of, it’s an easy way to make sure the weird behavior is still present in the `master` branch, and to add some debug-print statements. However, this is very temporary: I’ll delete `~/.julia/dev` and the `Manifest.toml` of my current environment when I’m done with debugging. And, if I’m interacting with that package over a longer period of time, it’s going to get cloned to a more permanent place in `~/Documents/Programming`.

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<div class="post-metadata">

**Author:** ![mkitti](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mkitti/32/12459_2.png) [@mkitti](https://discourse.julialang.org/u/mkitti)\
**Post date:** [July 2, 2023, 5:47am UTC](https://discourse.julialang.org/t/where-to-store-jl-files/101055/8 "2023-07-02T05:47:23Z")

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In short, you can put your Julia source files wherever you want. `~/.julia/dev` just happens to be a common default.

If you like to access them from `~/src`, you could always do `ln -s ~/.julia/dev ~/src/juliapkgs` on a \*nix system.

As others have explained, `Pkg.develop` and other tools such as `PkgTemplates.jl` default to populating `~/.julia/dev`. You can change this default by setting the environment variable [`JULIA_PKG_DEVDIR`](https://docs.julialang.org/en/v1/manual/environment-variables/#JULIA_PKG_DEVDIR).

You mentioned executables in `~/bin` and libraries in `~/lib`. Julia workflows usually do not involve producing a lot of files that would be appropriate to put there. One exception may be using [PakageCompiler.jl](https://julialang.github.io/PackageCompiler.jl/stable/) to produce apps, system images, or libraries.

As of Julia 1.9, Julia does produce native shared libraries (.so files) in `~/.julia/compiled/v1.9` but those are not really meant to be loaded outside of Julia.

Perhaps the most common workflow that may involve placing files in `~/bin` are executable scripts. I’ll show a minimal example of an “executable” project package.

```julia
$ tree -p src/HelloWorld.jl/
[drwxrwxr-x] src/HelloWorld.jl/
├── [drwxrwxr-x] bin
│ └── [-rwxrwxr-x] helloworld.jl
├── [-rw-rw-r--] Project.toml
└── [drwxrwxr-x] src
    └── [-rw-rw-r--] HelloWorld.jl

2 directories, 3 files

$ cat src/HelloWorld.jl/src/HelloWorld.jl 
module HelloWorld
    __init__ () = println("Hello World")
end

$ cat src/HelloWorld.jl/bin/helloworld.jl 
#!/bin/env julia
using Pkg
if length(ARGS) > 0 && ARGS[1] == "-q"
    io = devnull
else
    io = stdout
end
Pkg.activate(
    @ __FILE__ () |>
    x->(islink(x) ? readlink(x) : x) |>
    dirname |>
    dirname
    ; io
)

using HelloWorld

```

From Julia, one may load this package in the following way.

```julia
$ julia --project=src/HelloWorld.jl -e "using HelloWorld"
Hello World

```

If we just want a generic executable script, then we can use the `helloworld.jl` file.

```julia
$ src/HelloWorld.jl/bin/helloworld.jl 
  Activating project at `~/src/HelloWorld.jl`
Hello World

```

Now you may want this always on your shell’s path. Assuming that `~/bin` is on your shell’s path, you could then do the following.

```julia
$ ln -s ~/src/HelloWorld.jl/bin/helloworld.jl ~/bin

$ helloworld.jl 
  Activating project at `~/src/HelloWorld.jl`
Hello World

```

Additionally, I can also load this package into another Julia environment. Below I use `Pkg.develop` to incorporate it into a temporary Julia environment.

```julia
$ julia -e 'using Pkg; Pkg.activate(; temp=true); Pkg.develop(path="$(ENV["HOME"])/src/HelloWorld.jl"); using HelloWorld'
  Activating new project at `/tmp/jl_XxWuFq`
   Resolving package versions...
    Updating `/tmp/jl_XxWuFq/Project.toml`
  [ba1a46c8] + HelloWorld v0.0.0 `~/src/HelloWorld.jl`
    Updating `/tmp/jl_XxWuFq/Manifest.toml`
  [ba1a46c8] + HelloWorld v0.0.0 `~/src/HelloWorld.jl`
Hello World

```

Part of the reason I have the code arranged as a package is the because is the basic cacheable compilation unit in Julia.

```julia
$ ls ~/.julia/compiled/v1.9/HelloWorld
QoJsw_rFRaA.ji QoJsw_rFRaA.so

```

I hope that helps.

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<div class="post-metadata">

**Author:** ![alan](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/alan/32/15970_2.png) [@alan](https://discourse.julialang.org/u/alan)\
**Post date:** [July 2, 2023, 4:43pm UTC](https://discourse.julialang.org/t/where-to-store-jl-files/101055/9 "2023-07-02T16:43:41Z")

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Thanks to everyone who replied. These comments were extremely helpful.

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**Author:** ![stevengj](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/stevengj/32/71_2.png) [@stevengj](https://discourse.julialang.org/u/stevengj)\
**Post date:** [July 4, 2023, 1:31pm UTC](https://discourse.julialang.org/t/where-to-store-jl-files/101055/10 "2023-07-04T13:31:29Z")

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2 posts were split to a new topic: [Runtime arguments for **init**?](https://discourse.julialang.org/t/runtime-arguments-for-init/101170)

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**Author:** ![stevengj](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/stevengj/32/71_2.png) [@stevengj](https://discourse.julialang.org/u/stevengj)\
**Post date:** [July 4, 2023, 1:45pm UTC](https://discourse.julialang.org/t/where-to-store-jl-files/101055/11 "2023-07-04T13:45:55Z")

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A post was merged into an existing topic: [Runtime arguments for **init**?](https://discourse.julialang.org/t/runtime-arguments-for-init/101170/3)

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**Author:** ![stevengj](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/stevengj/32/71_2.png) [@stevengj](https://discourse.julialang.org/u/stevengj)\
**Post date:** [July 4, 2023, 1:50pm UTC](https://discourse.julialang.org/t/where-to-store-jl-files/101055/12 "2023-07-04T13:50:43Z")

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A post was merged into an existing topic: [Runtime arguments for **init**?](https://discourse.julialang.org/t/runtime-arguments-for-init/101170/5)