Increasing the amount of inotify watchers

https://github.com/guard/listen/wiki/Increasing-the-amount-of-inotify-watchers
https://confluence.jetbrains.com/display/IDEADEV/Inotify+Watches+Limit



If you are not interested in the technical details and only want to get Listen to work:

- If you are running Debian, RedHat, or another similar Linux distribution, run the following in a terminal:

```bash
echo fs.inotify.max_user_watches=524288 | sudo tee -a /etc/sysctl.conf && sudo sysctl -p
```

- If you are running ArchLinux, run the following command instead (see [here][] for why):

```bash
echo fs.inotify.max_user_watches=524288 | sudo tee /etc/sysctl.d/40-max-user-watches.conf && sudo sysctl --system
```

[here]: https://www.archlinux.org/news/deprecation-of-etcsysctlconf/

Then paste it in your terminal and press on enter to run it. 

## The technical details 

Listen uses inotify by default on Linux to monitor directories for changes. It's not uncommon to encounter a system limit on the number of files you can monitor. For example, Ubuntu Lucid's (64bit) inotify limit is set to 8192.

You can get your current inotify file watch limit by executing:

```bash
$ cat /proc/sys/fs/inotify/max_user_watches
```

When this limit is not enough to monitor all files inside a directory, the limit must be increased for Listen to work properly. 

You can set a new limit temporary with:

```bash
$ sudo sysctl fs.inotify.max_user_watches=524288
$ sudo sysctl -p
```

If you like to make your limit permanent, use:

```bash
$ echo fs.inotify.max_user_watches=524288 | sudo tee -a /etc/sysctl.conf
$ sudo sysctl -p
```

You may also need to pay attention to the values of `max_queued_events` and `max_user_instances` if Listen keeps on complaining.

## More info

* Manual of [inotify(7)](http://linux.die.net/man/7/inotify)
* Blog post: [limit of inotify (archive.org)](https://web.archive.org/web/20161106193425/http://blog.sorah.jp/2012/01/24/inotify-limitation)