Wrote a 6-line shell program which did the same thing. Program from scratch and invented a novel datastructure.
Someone is bound to mention the famous spar between Doug McIlroy andĭonald Knuth (much has been written regarding this: summary,ĭonald Knuth was asked to compute word frequencies from its input (“a”
#XONSH VS POWERSHELL CODE#
Lines of throwaway code is one of them - it’s nuts and we Shell programming at any volume above a few Some old-school Unix habits have persisted long past the point that Those userland dependencies on sed and tr and awk and even variants ofĮxpr(!) that get dragged in the second you try to get any actual work Portabilty problem, but (as Magnus implicitly points out) all It’s not so much the shell interpreters itself that are the Raymond, classic UNIX hacker, weighed in against shell:Īs a general scripting language shell sucks really badlyĬompared to anything new-school. Rewrite another one, hopefully in a real language this If anyone needs to tweak the task (including the original authorĪfter one month), they usually have to figure out what it does and Task in a stored procedure, this is the least maintainable As a one-offĬommand, I understand that’s a useful skill. I have a friend who says any system operation I can do in Python, heĬan do in an awk/ sed one-liner. Representations in Linux, and it is nearly impossible to take a consistent snapshot Unfortunately, over the years this has accumulated a plethora of different ad hoc Shell, which can’t define data structures, many Unices use the filesytem Kernel communicate complex datastructures to userspace? Influenced by People think about the rest of the system. The shell’s inability to natively represent datatypes affects how Often have an option to output structured data as JSON to losslesslyĮmit data for a real programming language. Plaintext, many newer tools ( kubectl, gcloud) But today, a plethora tools I use regularly do. The designers of shell did not envision so many tools requiring complexĭatatypes. Them between functions or compose them (no array of arrays). While Zsh and Bashĭo have arrays and associative arrays, there is no way to pass Good luck using a string in shell to hold non-trivial encodings orĬomplex datatypes are even more ad hoc. When creating a file–apparently the system prefers to silently fail Reserved character, but this reservation is (usually) not checked (the hostname and the path), but what if the filename contains a colon? Scp also uses a colon to separate two elements of a pair What if one of those strings needs to have a colon in it? ForĮxample, $PATH contains a colon-separated list-of-strings. The thorns of shell programming infect the rest of the system. Users for no good reason.” But there is a better way! Until we reach that point, computers will continue to frustrate their Shell says “We should strive to build our software… so thatĮxceptions like a filename with an odd character in it just don’t exist. ( a and b c) short of writing your own lexer in Overflow, there is no variant which expands to two arguments Then "$var" expands to oneĪrgument ( a "b c"), while $var expands to Quoting does not even solve the problem completely. Won’t notice until you try a specially-crafted string. While thisīehavior can be avoided with quotes around "$var", thisĭefault makes it easier to write shell scripts incorrectly in a way you Makeshift list) rather than command "name with space" byĭefault, when the programmer usually intends the latter. Representing complex datatypes is done on anĮven within simple datatypes, life is hard: ifĮxpands to command name with space ( $var is a Lists of lists of such can be represented as a line-separated list of Ls -l $file), or line-separated (like find). Space-separated (like shell arguments), tab-separated (like Lists of such can be colon-separated (like $PATH), After all, floats, ints, strings can all be encoded as strings. Interface.” Hence, it is not strongly typed it’s stringly Then there’s 50 feet of crap, and then there’s shell.”Ī cornerstone of UNIX wisdom is that “plaintext is the universal
As Billy Beane famously remarked, “There are strongly typed The distinguishing factor between these “real” programming languagesĪnd shell, for the purposes of this article, is the ability to defineĭatatypes. Need it to be maintainable, then shell scripts are a fine choice. If you can afford to baby-sit the task and don’t It is less maintainable than scripts written in real UNIX shell isn’t a real programming language, so stop using likeĭon’t get me wrong, shell is extremely useful and powerful.
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