DEV Community: Emili Parreno

Smoother Fonts for Alacritty on macOS

Emili Parreno — Sat, 23 Nov 2024 21:51:26 +0000

The font rendering in Alacritty is not as smooth as it is in iTerm. If your OCD is getting the best of you, just run this command to get smooth fonts in Alacritty.

defaults write org.alacritty AppleFontSmoothing -int 0

Voilà!

You can revert this change just deleting the default.

defaults delete org.alacritty AppleFontSmoothing

A curated list of shell commands and tools specific to macOS

Emili Parreno — Tue, 08 Mar 2022 12:42:23 +0000

https://git.herrbischoff.com/awesome-macos-command-line/about/

Development in Apple M1

Emili Parreno — Wed, 15 Dec 2021 12:03:36 +0000

I got a new laptop one week ago and I've been investigating different ways of setting up our dev environment. Here are my findings

Virtual Machines

There are different options

Virtual Box doesn't work as of today in Apple M1
Parallels, nice but you have to buy a license
UTM, very nice UI on top of QEMU. My preferred choice

If you run ARM virtual machines, it's fast as hell, feels like a native app, probably having a M1 Max with 10 cores and 64Gb of RAM helps bit :) but I wanted to use mainly x86 VMs and they are not so fast. I'll definitely use UTM in the future for running ARM based VMs.

Docker

If you run everything inside Docker, it works out of the box. I didn't experience any issues.

Apple's Rosetta

It turns out that the best virtualisation software comes already with you default MacOS installation and it's called Rosetta!

Here's how I set up my dev laptop

Duplicate your Terminal or iTerm app and give it a different name

I ended up with

In the x86 terminal, get info details (CMD + i) and check "Open using Rosetta"

That's it. Yes, really, that's all you need. Open your x86 terminal and you have an emulated x86 environment that just works.

If you install Hombrew in both envs it will be installed in different folders, the traditional /usr/local/Cellar for Intel based and the new one opt/hombrew/Cellar

I have a check in my .zshrc to load paths based on the arch. With that approach you need to be mindful about the arch you are running and loading the proper paths or executing the right code after login.

if [ $(arch) = 'arm64' ]; then
  ...
else
  ...
fi

I also added $(arch) to my prompt to know in which environment I am

Caveats

If you install the same app or library in both environments they may clash. Let's say you install MySQL in both ARM and x86 using Homebrew and you want to link the binary, you should choose on what env you do it. Just be careful about that.
For me hasn't been a problem because I mainly use x86 so I didn't install anything in the ARM env. Just avoid installing the same stuff in both envs.
If you really need to use both arches, an alternative could be using Rosetta to emulate x86 and UTM to run ARM based VMs so you don't risk messing with duplicated libraries or apps.

Calling system commands from within Ruby

Emili Parreno — Thu, 23 Sep 2021 16:41:22 +0000

Sometimes we need to execute system commands from within a Ruby app or script. You can find some methods in the Kernel module to accomplish this, but they behave slightly different. Let's take a look at all those methods and see what are their main differences.

`exec("command")`

This is the least common and least useful method for running external commands. exec replaces the current process (your Ruby script) by running the external command.

> exec('ls')

We rarely want this behaviour so let's see different ways to run system commands.

`command` or `%x{ command }`

Backticks are the easiest and quickest way to run a command. Simply enclose the command you want to run in backticks like this:

> `ls`
=> "bin\ncode\n"

If you prefer, you can get the same exact result using %x

> %x{ ls }
=> "bin\ncode\n"

Both return the standard output of running the command in a subshell.

`system("command")`

If you want to explicitly check if the command was found and ran successfully, you can use the system command. Unlike the backtick or %x method, system will execute the command and return true if the command was successful (exit status 0), false if it was unsuccessful (exit status 1) or nil if the command execution failed.

> system('ls')
bin          code
=> true

> system('ls x')
ls: x: No such file or directory
=> false

> system('foo')
=> nil

Special variables

For all of those methods mentioned above, you can access the PID and exit status of the unix process via the $? variable:

> system('ls')
bin       code
=> true

> $?.pid
=> 123

> $?.exitstatus
=> 0

`IO#popen`

This method executes the specified command as a subprocess, as a result it will return an IO object containing both input and output, allowing you to use some convenient methods to access the output and the PID.

> command = IO.popen("ls -l")
> command.pid
=> 123
> command.readlines
=> ["total 8\n",
 "-rwxr-xr-x  1 emili  staff   40 Feb 11 20:25 hello.rb\n",
 "drwxr-xr-x  4 emili  staff  136 Jan 30 13:16 foo.rb\n"]