When comparing Bash (Bourne-Again SHell) vs Haskell, the Slant community recommends Haskell for most people. In the question“What is the best programming language to learn first?” Haskell is ranked 26th while Bash (Bourne-Again SHell) is ranked 34th. The most important reason people chose Haskell is:
Haskell's referential transparency, consistency, mathematics-oriented culture, and heavy amount of abstraction encourage problem solving at a very high level. The fact that this is all built upon little other than function application means that not only is the thought process, but even concrete solutions are very transferable to any other language. In fact, in Haskell, [it's quite common for a solution to simply be written as an interpreter that can then generate code in some other language](http://programmers.stackexchange.com/questions/242795/what-is-the-free-monad-interpreter-pattern). Many other languages employ language-specific features, or work around a lack of features with heavy-handed design patterns that discourage abstraction, meaning that a lot of what is learned, and a lot of code that is needed to solve a particular problem just isn't very applicable to any other language's ecosystem.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Default shell on most systems
Bash is the default shell on virtually every UNIX system. Making it very portable across different systems and once you get used to it, you can use it everywhere.
Pro Plenty of examples and tutorials
Since this is very mature shell there is a lot of great examples and other resources describing how to do almost everything.
Pro Rich scripting capabilities on a single line
Want to run something 5 times? Write a throw-away loop: for i in 1 2 3 4 5; do date; done
If you need it 100 times? Not a problem: for i in {1..100}; do date; done
or: for ((i=0; i<100; ++i)); do date; done
How about emailing yourself when remote server is back online? Sure thing: while ! ping -c1 example.com &>/dev/null; do date; sleep 5; done && mailx -s 'server is back!' me@myself.com
Pro POSIX compatible
Pro Emacs-like keyboard control
By default, BASH uses shortcuts and concepts very similar to Emacs, so learning one often results in familiarity with the other.
Pro Rich built-in features
By default, there are many built-in features. They make really complex and reliable programs possible. In comparison to dash, for example, you can do the same tasks in less time and fewer lines of code.
Pro Variables and aliases are listed the way they are built
alias
and set
will list aliases and variables in a format that can be run directly with no modifications. Even if the values contain \n.
This is handy if you want to modify a value.
Pro Recursive globbing
ls **/*.log
for example is supported by Bash if you set shopt -s globstar
.
Pro Man page is a trove of wonders
While the manual "page" is nearly a hundred pages long, it is actually surprisingly succinct and stuffed with good information. It is often better than Googling for answers when writing shell scripts. The way it is written makes it easy to stumble upon useful new programming features just by flipping through it .
NOTE: If you find it dense and hard to read at the command line, look for the PDF version.
Pro vi mode is more comprehensive than on other shells
Vi editing mode works without a glitch. "_" will print you the last argument of the latest command (zsh won't). VI mode is fast off the bat - You don't have to reset any variable (like "KEYTIMEOUT" in zsh) for that.
Pro Copyright license is GPL 3+
Bash is licensed under the GNU General Public License ≥3, which gives much stronger assurances that the right to use it can't be restricted.
For example, Microsoft would not be able to claim in court that, even though they've distributed Bash with the GPLv3, a license that explicitly grants people freedom, now Bash is essentially proprietary due to software patents and everyone who uses Bash owes them money. (This may sound ludicrous to those who were not alive when Microsoft tried a similar scheme against Linux fifteen years ago).
The GPLv3 is a license that reflects the genuine ethical issues that arise when people give their time and skills to collaboratively build software. While most people wouldn't insist that their UNIX shell is licensed under the GPLv3+, it does matter and is a big PRO for Bash.
Pro Built-in 'help'... helps a lot
Built-in 'help' provides quick and efficient help on builtins and keywords.
Pro Rich scripting capabilities
BASH scripting is a rich and robust language.
Pro Highly transferable concepts
Haskell's referential transparency, consistency, mathematics-oriented culture, and heavy amount of abstraction encourage problem solving at a very high level. The fact that this is all built upon little other than function application means that not only is the thought process, but even concrete solutions are very transferable to any other language. In fact, in Haskell, it's quite common for a solution to simply be written as an interpreter that can then generate code in some other language. Many other languages employ language-specific features, or work around a lack of features with heavy-handed design patterns that discourage abstraction, meaning that a lot of what is learned, and a lot of code that is needed to solve a particular problem just isn't very applicable to any other language's ecosystem.
Pro Forces you to learn pure functional programming
It is pure and does not mix other programming paradigms into the language. This forces you to learn functional programming in its most pure form. You avoid falling back on old habits and learn an entirely new way to program.
Pro Open source
All Haskell implementations are completely free and open source.
Pro Mathematical consistency
As Haskell lends itself exceedingly well to abstraction, and borrows heavily from the culture of pure mathematics, it means that a lot more code conforms to very high-level abstractions. You can expect code from vastly different libraries to follow the same rules, and to be incredibly self-consistent. It's not uncommon to find that a parser library works the same way as a string library, which works the same way as a window manager library. This often means that getting familiar and productive with new libraries is often much easier than in other languages.
Pro Referentially transparent
Haskell's Purely Functional approach means that code is referentially transparent. This means that to read a function, one only needs to know its arguments. Code works the same way that expressions work in Algebra class. There's no need to read the whole source code to determine if there's some subtle reference to some mutable state, and no worries about someone writing a "getter" that also mutates the object it's called on. Functions are all directly testable in the REPL, and there's no need to remember to call methods in a certain order to properly initialize an object. No breakage of encapsulation, and no leaky abstractions.
Pro Hand-writeable concise syntax
Conciseness of Haskell lets us to write the expression on the whiteboard or paper and discuss with others easily. This is a strong benefit to learn FP over other languages.
Pro Very few language constructs
The base language relies primarily on function application, with a very small amount of special-case syntax. Once you know the rules for function application, you know most of the language.
Pro Quick feedback
It's often said that, in Haskell, if it compiles, it works. This short feedback loop can speed up learning process, by making it clear exactly when and where mistakes are made.
Pro Functions curry automatically
Every function that expects more than one arguments is basically a function that returns a partially applied function. This is well-suited to function composition, elegance, and concision.
Pro Easy to read
Haskell is a very terse language, particularly due to its type inference. This means there's nothing to distract from the intent of the code, making it very readable. This is in sharp contrast to languages like Java, where skimming code requires learning which details can be ignored. Haskell's terseness also lends itself to very clear inline examples in textbooks, and makes it a pleasure to read through code even on a cellphone screen.
Pro Popular in teaching
Haskell is really popular in universities and academia as a tool to teach programming. A lot of books for people who don't know programming are written around Haskell. This means that there are a lot of resources for beginners in programming with which to learn Haskell and functional programming concepts.
Pro Easy syntax for people with a STEM degree
Since the basic syntax is very similar to mathematics, Haskell syntax should be easy for people who have taken higher math courses since they would be used to the symbols used in maths.
Pro Powerful categorical abstractions
Makes categorical higher order abstractions easy to use and natural to the language.
Cons
Con Extremely complicated and inconsistent rules
In Bash, exceptions are the rule, not even all being described by the main page.
There are a grand total of 5 different ways of quoting, sometimes even when one does not want to, for instance in command substitutions. These are all based around preserving the literal meaning of every character, with an exception list. There is even an exception list to the exception list in 4 of the 5, regarding how the backslash behaves! The behavior of the backslash is also one of the quoting rules, so naturally, it also has an exception in how it works when it stands before a newline as compared to other characters.
Bash has several layers of interpretations, all to be kept in mind:
The ~ expands to the home of the current user. So if you store it in a variable, can you use it that way? Nope: tilde expansion comes before variable expansion.
Aha, so that's how it works! Then, since applying quotation happens after redirections are set up, it must mean that redirecting within quotes works, right? Nope: there is an exception! If a redirection symbol is not quoted, quotation around the symbol is observed, but is not removed. So, since variable expansion also comes after setting up redirections, and no exceptions are described here in the man page, getting the name of a file from a variable and using it as a target should not work, right? No: redirection does not actually take place when the symbols are being read, the symbols are merely removed and are noted for later, right before when the actual command runs.
Apart from 5 types of quotation, there are basically 2 quoting phases, 2 word splitting phases (with only one being controllable), and a tokenization phase on top of that.
If you have a command, it could be an alias, a special built in, a non-special built in, a symbolic link to a file, a regular file, a function, with different rules regarding how they can be overridden, if redirection happens before or after arguments have been passed (what does "time my_command 2>&1 >log_file" do?), etc.
This list is admittedly long, but it doesn't even scratch the surface of the bloat, complexity and inconsistencies of Bash.
Con GPL3 is not compatible with Apple's lawyers
Apple, one of the largest distributors of UNIX systems, only ships an ancient version of bash that predates the iPhone.
No one knows why as Apple hasn't said, but the version Apple includes in MacOS is from right before the license was updated to version 3 of the GNU GPL (General Public License). Other major companies (IBM, Microsoft) have had no problem shipping the latest version of bash
, so it's unclear what Apple's lawyers are averse to. The GPL has always said that if you distributed a program, you granted everyone the right to use it freely. The biggest change in version 3 was the addition, "...and that includes software patents."
This was necessary because back in 2006 Microsoft was demanding that any company that uses Linux pay them or get sued for infringing on their patents. They even took some companies, like TomTom, to court. No software which can be restricted retroactively like that is truly free, so GPL 3+ includes a clause saying that if you distribute the program, then you are also granting license to any patents you own that are necessary to run it.
What patents Apple has that bash could possibly infringe on is a mystery, but the bigger question is, Why does Apple even care? So what if they are granting people the right to run bash without being sued by Apple. It's not like they were planning on doing that, right?
Even though it is not bash's fault that it is not Apple Lawyer-approved, this is a CON for it because a lot of people use Apple products. While there are methods like brew
to install a current version of bash, Apple does not make it obvious to their customers what they are missing.
Con Compatibility can be a curse
One of bash's claims to fame is compatibility with previous versions of itself and historic shells. But, doing that means that new features are often written in tortured, awkward syntax that is not easy to learn. For example, bash uses the POSIX way of doing arithmetic: to add 5+3 you must put the numbers in double parentheses with a dollar sign at the start: x=$((5+3)). It is true that many shells suffer from this same CON, but since bash is such an important shell, it has less wiggleroom to ditch clunky ideas that might break existing scripts.
Con Lags behind on features compared to ZSH and Fish
People who wants power features or to customize their shell experience use zsh or fish.
Con Filename expansion is not consistent
filename expansion is not consistent. "echo *" will print the names of the files in your current dir, if there are any... and will print "*" if there are none.
Con Non-intuitive shell expansion in for loops
If there are no .sh files, this will print mask itself:
for filename in *.sh; do
echo $filename
done
Con No out-of-the-box command autocompletion
To have command autocompletion in bash you need to install third-party plug-ins.
Con One of the most dangerous languages around
What it is mostly used for are file system operations. Guess what it is bad at? Operating on files. It automatically splits and carries out filename expansion on every single string resulting from variable expansion and command substitution unless quoted, by default on whitespace, whilst spaces are very common in filenames.
Before that, it even does pathname expansion, so woe to anywone who does not want to actually operate on files, but has a globbing metacharacter stored anywhere in a variable.
This means what you store in a variable is not going to be what will ACTUALLY be accessed.
If an empty variable is unquoted, it disappears completely due to word splitting, sometimes leading to applications signalling a missing parameter at a wrong position.
If quoted however, said variables cannot be iterated over in a loop, no matter what character one uses for word splitting.
If you use any globbing pattern with a command, be sure to use -- after the option arguments or if none are present, before starting the pattern with a mandatory ./
Otherwise, another Bash script run gone wrong or a hacker can create files named like an option ("-f", for instance) and your program will happily accept it as such, if it results from globbing.
For interactive use, it is convenient. For programming, it is a no-go.
Con Language extensions lead to unfamiliar code
Haskell's language extensions, while making the language incredibly flexible for experienced users, makes a lot of code incredibly unfamiliar for beginners. Some pragmas, like NoMonomorphismRestriction, have effects that seem completely transparent in code, leading beginners to wonder why it's there. Others, like ViewPatterns, and particularly TemplateHaskell, create completely new syntax rules that render code incomprehensible to beginners expecting vanilla function application.
Con Difficult learning curve
Haskell lends itself well to powerful abstractions - the result is that even basic, commonly used libraries, while easy to use, are implemened using a vocabularly that requires a lot of backround in abstract mathematics to understand. Even a concept as simple as "combine A and B" is often, both in code and in tutorials, described in terms of confusing and discouraging terms like "monad", "magma", "monoid", "groupoid", and "ring". This also occasionally bears its ugly head in the form of complicated error messages from type inference.
Con Package manager is unstable & lacking features
Cabal (There are other choices but this is the most popular) can not uninstall a package. Also working at a few locations it is difficult to have the same environment for each one be the same.
Con You have to learn more than just FP
Haskell is not only a functional language but also a lazy, and statically typed one. Not only that but it's almost necessary to learn about monads before you can do anything useful.
Con Symbols everywhere
Haskell allows users to define their own infix operators, even with their own precedence. The result is that some code is filled with foreign looking operators that are assumed to be special-case syntax. Even for programmers who know they're just functions, operators that change infix precedence can potentially break expectations of how an expression is evaluated, if not used with care.
Con Obscure ugly notation
0 = 1
Using "=" like this: <code>
-- Using recursion (with pattern matching)
factorial 0 = 1
factorial n = n * factorial (n - 1) </code> Example from https://en.wikipedia.org/wiki/Haskell_(programming_language)
is quite simply annoying aesthetics.
Con Documentation for most packages is short and lacking
A few Haskell packages are well documented but this is the exception, not the rule.
Most of the time a list of function signatures is what passes for documentation.
Con Too academic, hard to find "real world" code examples
Con You need some time to start seeing results
Haskell's static typing, while helpful when building a project, can be positively frustrating for beginners. Quick feedback for errors means delaying the dopamine hit of code actually running. While in some languages, a beginner's first experience may be their code printing "Hello World" and then crashing, in Haskell, similar code would more likely be met with an incomprehensible type error.
Con Lazily evaluated
Haskell's lazy evaluation implies a level of indirection - you're not passing a value, you're passing a thunk. This is often difficult to grasp not just for beginners, but for experienced programmers coming from strictly evaluated languages. This also means that, since for many, strict evaluation is their first instinct, initial expectations of a function's performance and complexity are often broken.
Con Only pure functional programming
Not proper functional programming but a subset of the style called pure functional programming.