# File system notifications for Go

[![GoDoc](https://godoc.org/github.com/howeyc/fsnotify?status.png)](http://godoc.org/github.com/howeyc/fsnotify)

Cross platform: Windows, Linux, BSD and OS X.

## Moving Notice

There is a fork being actively developed with a new API in preparation for the Go Standard Library:
[github.com/go-fsnotify/fsnotify](https://github.com/go-fsnotify/fsnotify)

## Example:

```go
package main

import (
	"log"

	"github.com/howeyc/fsnotify"
)

func main() {
	watcher, err := fsnotify.NewWatcher()
	if err != nil {
		log.Fatal(err)
	}

	done := make(chan bool)

	// Process events
	go func() {
		for {
			select {
			case ev := <-watcher.Event:
				log.Println("event:", ev)
			case err := <-watcher.Error:
				log.Println("error:", err)
			}
		}
	}()

	err = watcher.Watch("testDir")
	if err != nil {
		log.Fatal(err)
	}
	
	// Hang so program doesn't exit
	<-done

	/* ... do stuff ... */
	watcher.Close()
}
```

For each event:
* Name
* IsCreate()
* IsDelete()
* IsModify()
* IsRename()

## FAQ

**When a file is moved to another directory is it still being watched?**

No (it shouldn't be, unless you are watching where it was moved to).

**When I watch a directory, are all subdirectories watched as well?**

No, you must add watches for any directory you want to watch (a recursive watcher is in the works [#56][]).

**Do I have to watch the Error and Event channels in a separate goroutine?**

As of now, yes. Looking into making this single-thread friendly (see [#7][])

**Why am I receiving multiple events for the same file on OS X?**

Spotlight indexing on OS X can result in multiple events (see [#62][]). A temporary workaround is to add your folder(s) to the *Spotlight Privacy settings* until we have a native FSEvents implementation (see [#54][]).

**How many files can be watched at once?**

There are OS-specific limits as to how many watches can be created:
* Linux: /proc/sys/fs/inotify/max_user_watches contains the limit,
reaching this limit results in a "no space left on device" error.
* BSD / OSX: sysctl variables "kern.maxfiles" and "kern.maxfilesperproc", reaching these limits results in a "too many open files" error.


[#62]: https://github.com/howeyc/fsnotify/issues/62
[#56]: https://github.com/howeyc/fsnotify/issues/56
[#54]: https://github.com/howeyc/fsnotify/issues/54
[#7]: https://github.com/howeyc/fsnotify/issues/7