Entr overview

Today, I would like to introduce you to the projectentr.
I discovered this project randomly a while ago, but I had been searching for a tool
like this for a while.

The goal of this tool is to provide a simple command which can launch
a specified command when some files are modified.
Concretely, this tool can be useful if you are searching for an alternative to
livereload, but not related to a specific language and not related to a full
blownIDE

Example

I often use it to automatically launch tests forGolang projects I am
developping.

Imagine, I wish to test the following function in the
pkg.go file:

// Inc returns the op1 integer incremented by one unitfuncInc(op1int)int{returnop1+1}

I wish to test it, with this test inpkg_test.go:

funcTest_Inc(t*testing.T){actual:=Inc(1)ifactual!=2{t.Errorf("Expecting: <2>, got <%d>",actual)}}

I would launch my tests continuously with the following command:

find*.go | entr-c-s"go test ."

Here is a live preview of the result (using asciinema):

At first, the test is not working, but as soon as the test file is updated, the
test is launched again.
The specificity here, is to use the-c flag, in order to clear the screen
before launching the new command.

You can find the full list of optionshere

How does it work ?

In order to avoidpolling,
entr uses file system events
(kqueue with BSD,
inotify with Linux).

The full source code is available here:

How to get it ?

If you wish to install it, it's really easy, just use your Linux distribution package:

Ubuntu, Debian, Mint, ... :

$ apt install entr

Centos, ... :

$ yum install entr

MacOS :

$ brew install entr