# Custom flags to Jupyter

**URL:** <https://discourse.julialang.org/t/custom-flags-to-jupyter/4852>\
**Category:** General Usage\
**Tags:** jupyter\
**Created:** [July 14, 2017, 1:42pm UTC](https://discourse.julialang.org/t/custom-flags-to-jupyter/4852 "2017-07-14T13:42:42Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![andreasnoack](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/andreasnoack/32/27_2.png) [@andreasnoack](https://discourse.julialang.org/u/andreasnoack)\
**Post date:** [July 14, 2017, 1:42pm UTC](https://discourse.julialang.org/t/custom-flags-to-jupyter/4852/1 "2017-07-14T13:42:42Z")

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Is there a way to launch the notebook with custom flags to the Julia instance? I.e. without changing the `kernel.json` file. In particular, I’d like to pass `--compilecache=no`.

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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 14, 2017, 1:45pm UTC](https://discourse.julialang.org/t/custom-flags-to-jupyter/4852/2 "2017-07-14T13:45:10Z")

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You could install your own `kernel.json` file?

IJulia could make this easier by adding an `IJulia.addkernel(name, options...)` function, I guess.

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**Author:** ![andreasnoack](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/andreasnoack/32/27_2.png) [@andreasnoack](https://discourse.julialang.org/u/andreasnoack)\
**Post date:** [July 14, 2017, 1:51pm UTC](https://discourse.julialang.org/t/custom-flags-to-jupyter/4852/3 "2017-07-14T13:51:37Z")

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Something like that would be useful. Right now, you’ll have to launch workers as well as the master process with `--compilecache=no` when then add workers on a system that doesn’t share file system with the system where your master process is running. Having a custom kernel for that would probably be fine if it could be constructed as easily as you suggest.

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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 14, 2017, 5:37pm UTC](https://discourse.julialang.org/t/custom-flags-to-jupyter/4852/4 "2017-07-14T17:37:16Z")

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I’ve [just added](https://github.com/JuliaLang/IJulia.jl/commit/92aedf945f127399c62f428c38147e75635dd727) this to the latest IJulia master. Now you can do

```julia
using IJulia
installkernel("Julia no-cache", "--compilecache=no")

```

to install a custom kernel that launches `julia` with the `--compilecache=no` option.

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<div class="post-metadata">

**Author:** ![andreasnoack](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/andreasnoack/32/27_2.png) [@andreasnoack](https://discourse.julialang.org/u/andreasnoack)\
**Post date:** [July 14, 2017, 5:57pm UTC](https://discourse.julialang.org/t/custom-flags-to-jupyter/4852/5 "2017-07-14T17:57:12Z")

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Great. Thanks.