Don’t Ever Use Zsh

Seriously, It will Destroy You

"Bash is the only shell scripting language permitted for executables." ([Google Style Guide](Bash is the only shell scripting language permitted for executables.))

What you are actually saying is,“I’m an inexperienced, uninformed, probably Mac cultist who has trouble with basic spelling and prioritizes gaudy command prompts over professional effectiveness” like these, uninformed, people.

Here is a list of some of the advantages they claim. These four advantages are copied verbatim from Anthony Heddings surprisingly high-SEO-ranked write-up on HowToGeek, a publication that has lost serious credibility for allowing this. Even though Anthony is probably a great dude these ideas are completely stupid.

1. Automatic cd: Just type the name of the directory
2. Recursive path expansion: For example “/u/lo/b” expands to “/usr/local/bin”
3. Spelling correction and approximate completion: If you make a minor mistake typing a directory name, ZSH will fix it for you
4. Plugin and theme support: ZSH includes many different plugin frameworks

Brain-Dead Muscle Memory

All of these “advantages” are actually horrible flaws any engineer who values productivity on all Linux and Unix systems will immediately identify. The main reason you learned Vi properly was the same reason you should absolutely shun Zsh.

“But cd is Easier”

This shows you don’t even know Bash because setting a CDPATH does the same thing.

“But I Can Do /u/lo/b”

You can also just use tab completion which prompts when you get things wrong and is far faster, supported everywhere, and safer — especially if you have set -o vi. Usually you are doing this in conjunction with cd so CDPATH comes into play.

“It Fixes My Spelling”

Do you really need your shell interpreter to correct your spelling? Are you seriously openly admitting you are that pathetic? If you are then nothing is going to save you, least of which some broken, non-standard, dangerous shell that Apple prefers. At least we all now know that about you. And yes, we are openly judging you. Apparently you don’t prioritize accuracy or cross-platform productivity in your production work. “Yeah — sure — we’d love to have you join our pentesting or systems operations team. Umhummm.”

“It has Plugins and Pretty Themes”

“Zsh is the new hotness. Well newer and hotter than Bash anyway, since the first version of Bash was released in June 1989, while the young and peppy Zsh was released in December 1990. In large parts thanks to the configuration “skin” oh-my-zsh, Zsh has gained a lot of popularity during the last year or so. I have used it for a few months myself and could not be happier, unless it produced chocolate ice cream note to shell developers.

This is a guide on why you need it and how you install, configure and use it. Sometimes just with links to the relevant sites.

This is written partly for my colleagues, who I think would benefit from using Zsh instead of Bash on their desktops and on our servers.

Smacks forehead. Hey Fendrich, we all pity your “colleagues” and want to remind you that https (not http) is actually a thing in 2020. Did you seriously just recommend swapping out Bash on “servers” as well as desktops?

Using Oh-My-Zsh is almost immediately the first advantage most Zsh users cite. Some of them have learned not to lead with that because any actual engineer is laughing his or her ass off when they list this.

This has nothing to do with color and customization. We all love it and do it. We just don’t depend on a bloated, broken, insecure plugin system for it.

Plugins are for lazy, incompetent Mac users and junior Linux engineers who don’t know how to minimally customize their own shell — let alone write any actual shell code in any language. Besides, if they did know how to write enough shell to customize without using a plugin they would quickly realize all of Zsh’s other massive engineering and design flaws.

Official Shell of Apple

Zsh is now the official shell of Apple. You know. The company that removed the Escape key because their technical design team is just that completely brain dead. “What’s Vi?” shakes head We know they are stupid because they were practically forced to add it back the same year Apple lost a massive class-action lawsuit for actually selling such a completely broken keyboard.

Why did they remove it? Because they preferred a super pretty, battery-draining piece of colorful crap in its place.

“I’m sure Apple has their reasons. Their engineers are geniuses! How dare you besmirch the memory of the great Steve Jobs! Apple support centers are filled with geniuses just like him!”

Okkkkaaay.

Apple Hates Giving Back

The true reason Apple picked Zsh is because they are a heartless greedy company that never gives anything back to the open source community but loves to take and take and take claiming all the credit for itself. The idea that a license might require them to do the right thing terrifies them — again, because Apple simply has no soul at all.

Bash has Been Default for Decades

Bash continues to be the official default shell of all Linux systems. Ask yourself, do you want to learn some broken new default shell from a company that removed the Escape key and just wants to avoid GPLv3 or do you want to learn and use the Linux shell available on millions of systems by default? It’s as simple as that.

But if you are still here and care about some objective and selfish reasons not to ever look at zsh then keep reading.

Zsh Actually Adds Nothing

Zsh provides no additional value over Bash, period. That is the biggest reason of all. The burden of proof is on Zsh to prove it is worth throwing out the default shell on all Linux systems for over two decades.

No Exported Functions

Zsh handicaps you by preventing you from using critical Bash functionality such as exported functions (which is how all Bash completion on every Linux system is created in /etc/bash_completion.d).

No Support for Variable Name References

Another amazing thing Bash has that Zsh throws up on for no good reason is something called Variable Name References.

Did you know that Bash has pointers? Well, effectively that’s what they are. They are almost unheard of in the wild despite their incredible power. Here’s how they work:

#!/bin/bash

  declare -n avar
  some=thing
  avar=some
  echo $avar # prints "thing"

There are so many applications of this it would be a full article just to describe them, passing names of variables to a function, saving a case with an associative array lookup containing the name of a function instead, the list could to on and on. Knowing nameref exists in Bash and don’t exist in Zsh is almost enough by itself to kick Zsh off your computer.

Dangerous Floating Point Support

Zsh tempts you with floating point math in $((3/2)) arithmetic variable expansion — which seems great at first — until you realize that people will attempt to use scripts code on other Linux and Unix systems where /bin/sh is not Zsh and you scripts will horribly and disastrously fail. The safest way to use floating point has always been and continues to be the bc command. Always assume any shell script is not floating point safe.

Encourages Bad Practices

There are a lot of little bad practices that Zsh users begin to adopt without even realizing they are destroying their ability to work on a default Linux system.

For example, some YouTubers have encouraged users to use < instead of cat to output a file confusing beginners who didn’t know this was never supported in any other shell but Zsh. (It’s actually a bug that should never have worked in the first place.)

# WRONG!
  < somefile

Use cat instead.

cat somefile

Failure to Meet POSIX Compliance

Zsh is not POSIX compliant as people claim. Use of that broken redirection suggestion is proof of that. The floating point math is another. If you are going to learn non-POSIX things they should be for the default Linux shell, not some broken upstart that can’t decide what it wants to be. If you want POSIX use /bin/dash instead, which is what /bin/sh is linked to on all Debian-based systems.