Am I crazy in thinking that bash is good enough for production?
Am I crazy in thinking that bash is good enough for production?
This may make some people pull their hair out, but I’d love to hear some arguments. I’ve had the impression that people really don’t like bash, not from here, but just from people I’ve worked with.
There was a task at work where we wanted something that’ll run on a regular basis, and doesn’t do anything complex aside from reading from the database and sending the output to some web API. Pretty common these days.
I can’t think of a simpler scripting language to use than bash. Here are my reasons:
- Reading from the environment is easy, and so is falling back to some value; just do
${VAR:-fallback}; no need to write another if-statement to check for nullity. Wanna check if a variable’s set to something expected?if [[ <test goes here> ]]; then <handle>; fi - Reading from arguments is also straightforward; instead of a
import os; os.args[1]in Python, you just do$1. - Sending a file via HTTP as part of an
application/x-www-form-urlencodedrequest is super easy withcurl. In most programming languages, you’d have to manually open the file, read them into bytes, before putting it into your request for the http library that you need to import.curlalready does all that. - Need to read from a
curlresponse and it’s JSON? Reach forjq. - Instead of having to set up a connection object/instance to your database, give
sqlite,psql,duckdbor whichever cli db client a connection string with your query and be on your way. - Shipping is… fairly easy? Especially if docker is common in your infrastructure. Pull
Ubuntuordebianoralpine, install your dependencies through the package manager, and you’re good to go. If you stay within Linux and don’t have to deal with differences in bash and core utilities between different OSes (looking at you macOS), and assuming you tried to not to do anything too crazy and bring in necessary dependencies in the form of calling them, it should be fairly portable.
Sure, there can be security vulnerability concerns, but you’d still have to deal with the same problems with your Pythons your Rubies etc.
For most bash gotchas, shellcheck does a great job at warning you about them, and telling how to address those gotchas.
There are probably a bunch of other considerations but I can’t think of them off the top of my head, but I’ve addressed a bunch before.
So what’s the dealeo? What am I missing that may not actually be addressable?
We are not taking about use of Bash in dev vs use Bash in production. This is imho incorrect question that skirts around the real problem in software development. We talk about use of Bash for simple enough tasks where code is rarely changed ( if not written once and thrown away ) and where every primitive language or DSL is ok, where when it comes to building of medium or complex size software systems where decomposition, complex data structures support, unit tests, error handling, concurrency, etc is a big of a deal - Bash really sucks because it does not allow one to deal with scaling challenges, by scaling I mean where you need rapidly change huge code base according changes of requirements and still maintain good quality of entire code. Bash is just not designed for that.
But not everything needs to scale, at least, if you don’t buy into the doctrine that everything has to be designed and written to live forever. If robust, scalable solutions is the nature of your work and there’s nothing else that can exist, then yeah, Bash likely have no place in that world. If you need any kind of handling more complicated than just getting an error and doing something else, then Bash is not it.
Just because Bash isn’t designed for something you want to do, doesn’t mean it sucks. It’s just not the right tool. Just because you don’t practice law, doesn’t mean you suck; you just don’t do law. You can say that you suck at law though.
Yep. Like said - "We talk about use of Bash for simple enough tasks ... where every primitive language or DSL is ok", so Bash does not suck in general and I myself use it a lot in proper domains, but I just do not use it for tasks / domains with complexity ( in all senses, including, but not limited to team work ) growing over time ...
Honestly, if a script grows to more than a few tens of lines I'm off to a different scripting language because I've written enough shell script to know that it's hard to get right.
Shellcheck is great, but what's greater is a language that doesn't have as many gotchas from the get go.
What gave you the impression that this was just for development? Bash is widely used in production environments for scripting all over enterprises. The people you work with just don’t have much experience at lots of shops I would think.
It’s just not wise to write an entire system in bash. Just simple little tasks to do quick things. Yes, in production. The devops world runs on bash scripts.
Bash is widely used in production environments for scripting all over enterprises.
But it shouldn't be.
The people you work with just don’t have much experience at lots of shops I would think.
More likely they do have experience of it and have learnt that it's a bad idea.
I’ve never had that impression, and I know that even large enterprises have Bash scripts essentially supporting a lot of the work of a lot of their employees. But there are also many very loud voices that seems to like screaming that you shouldn’t use Bash almost at all.
You can take a look at the other comments to see how some are entirely turned off by even the idea of using bash, and there aren’t just a few of them.
One thing that I don't think anyone else has mentioned is data structures. Bash does have arrays and hashmaps at least but I've found that working with them is significantly more awkward than in e.g. python. This is one of several reasons for why bash doesn't scale up well, but sure for small enough scripts it can be fine (if you don't care about windows)
I think I mentioned it, but inverse: The only data type I'm comfortable with in bash are simple string scalars; plus some simple integer handling I suppose. Once I have to think about stuff like
"${foo[@]}"and the like I feel like I should've switched languages already.Plus I rarely actually want arrays, it's way more likely I want something in the shape of
@dataclass(frozen=True) class Foo: # … foos: set[Foo] = …That’s definitely worth mentioning indeed. Bash variables, aside from arrays and hashmaps that you get with
declare, are just strings. Any time you need to start capturing a group of data and do stuff with them, it’s a sign to move on. But there are many many times where that’s unnecessary.
I've worked in bash. I've written tools in bash that ended up having a significant lifetime.
Personally, you lost me at
reading from the database
Database drivers exist for a reason. Shelling out to a database cli interface is full of potential pitfalls that don't exist in any language with a programmatic interface to the database. Dealing with query parameterization in bash sounds un-fun and that's table stakes, security-wise.
Same with making web API calls. Error handling in particular is going to require a lot of boilerplate code that you would get mostly for free in languages like Python or Ruby or Go, especially if there's an existing library that wraps the API you want to use in native language constructs.
This is almost a strawman argument.
You don’t have to shell out to a db cli. Most of them will gladly take some SQL and spit out some output. Now that output might be in some tabular format with some pretty borders around them that you have to deal with, if you are about the output within your script, but that’s your choice and so deal with it if it’s within your comfort zone to do so. Now if you don’t care about the output and just want it in some file, that’s pretty straightforward, and it’s not too different from just some cli that spits something out and you’ve redirected that output to a file.
I’ve mentioned in another comment where if you need to accept input and use that for your queries, psql is absolutely not the tool to use. If you can’t do it properly in bash and tools, just don’t. That’s fine.
With web API calls, same story really; you may not be all that concerned about the response. Calling a webhook? They’re designed to be a fire and forget, where we’re fine with losing failed connections. Some APIs don’t really follow strict rules with REST, and will gladly include an “ok” as a value in their response to tell you if a request was successful. If knowing that is important to the needs of the program, then, well, there you have it. Otherwise, there are still ways you can get the HTTP code and handle appropriately. If you need to do anything complex with the contents of the response, then you should probably look elsewhere.
My entire post is not to say that “you can do everything in bash and you should”. My point is that there are many cases where bash seems like a good sufficient tool to get that simple job done, and it can do it more easily with less boilerplate than, say, Python or Ruby.
I'm afraid your colleagues are completely right and you are wrong, but it sounds like you genuinely are curious so I'll try to answer.
I think the fundamental thing you're forgetting is robustness. Yes Bash is convenient for making something that works once, in the same way that duct tape is convenient for fixes that work for a bit. But for production use you want something reliable and robust that is going to work all the time.
I suspect you just haven't used Bash enough to hit some of the many many footguns. Or maybe when you did hit them you thought "oops I made a mistake", rather than "this is dumb; I wouldn't have had this issue in a proper programming language".
The main footguns are:
- Quoting. Trust me you've got this wrong even with
shellcheck. I have too. That's not a criticism. It's basically impossible to get quoting completely right in any vaguely complex Bash script. - Error handling. Sure you can
set -e, but then that breaks pipelines and conditionals, and you end up with really monstrous pipelines full ofpipefailnoise. It's also extremely easy to forgetset -e. - General robustness. Bash silently does the wrong thing a lot.
instead of a
import os; os.args[1]in Python, you just do$1No. If it's missing
$1will silently become an empty string.os.args[1]will throw an error. Much more robust.Sure, there can be security vulnerability concerns, but you’d still have to deal with the same problems with your Pythons your Rubies etc.
Absolutely not. Python is strongly typed, and even statically typed if you want. Light years ahead of Bash's mess. Quoting is pretty easy to get right in Python.
I actually started keeping a list of bugs at work that were caused directly by people using Bash. I'll dig it out tomorrow and give you some real world examples.
Agreed.
Also gtfobins is a great resource in addition to shellcheck to try to make secure scripts.
For instance I felt upon a script like this recently:
#!/bin/bash # ... some stuff ... tar -caf archive.tar.bz2 "$@"Quotes are OK, shellcheck is happy, but, according to gtfobins, you can abuse tar, so running the script like this:
./test.sh /dev/null --checkpoint=1 --checkpoint-action=exec=/bin/shends up spawning an interactive shell...So you can add up binaries insanity on top of bash's mess.
I imagine adding
--so it becomestar -caf archive.tar.bz2 -- "$@"would fix that specific caseBut yeah, putting bash in a position where it has more rights than the user providing the input is a really bad idea
Quotes are OK, shellcheck is happy, but, according to gtfobins, you can abuse tar, so running the script like this: ./test.sh /dev/null --checkpoint=1 --checkpoint-action=exec=/bin/sh ends up spawning an interactive shell…
This runs into a part of the unix philosophy about doing one thing and doing it well: Extending programs to have more (absolutely useful) functionality winds up becoming a security risk. The shell is generally geared towards being a collection of shortcuts rather than a normal, predictable but tedious API.
For a script like that you'd generally want to validate that the input is actually what you expect if it needs to handle hostile users, though. It'll likely help the sleepy users too.
gtfobins
Meh, most in that list are just "if it has the SUID bit set, it can be used to break out of your security context".
I don't disagree with your point, but how does
set -ebreak conditionals? I use it all the time without issuesPipefail I don't use as much so perhaps that's the issue?
It means that all commands that return a non-zero exit code will fail the script. The problem is that exit codes are a bit overloaded and sometimes non-zero values don't indicate failure, they indicate some kind of status. For example in
git diff --exit-codeorgrep.I think I was actually thinking of
pipefailthough. If you don't set it then errors in pipelines are ignored, which is obviously bad. If you do then you can't usegrepin pipelines.
I honestly don’t care about being right or wrong. Our trade focuses on what works and what doesn’t and what can make things work reliably as we maintain them, if we even need to maintain them. I’m not proposing for bash to replace our web servers. And I certainly am not proposing that we can abandon robustness. What I am suggesting that we think about here, is that when you do not really need that robustness, for something that may perhaps live in your production system outside of user paths, perhaps something that you, your team, and the stakeholders of the particular project understand that the solution is temporary in nature, why would Bash not be sufficient?
I suspect you just haven’t used Bash enough to hit some of the many many footguns.
Wrong assumption. I’ve been writing Bash for 5-6 years now.
Maybe it’s the way I’ve been structuring my code, or the problems I’ve been solving with it, in the last few years after using
shellcheckandbash-language-serverthat I’ve not ran into issues where I get fucked over by quotes.But I can assure you that I know when to dip and just use a “proper programming language” while thinking that Bash wouldn’t cut it. You seem to have an image of me just being a “bash glorifier”, and I’m not sure if it’ll convince you (and I would encourage you to read my other replies if you aren’t), but I certainly don’t think bash should be used for everything.
No. If it's missing
$1will silently become an empty string.os.args[1]will throw an error. Much more robust.You’ll probably hate this, but you can use
set -uto catch unassigned variables. You should also use fallbacks wherever sensible.Absolutely not. Python is strongly typed, and even statically typed if you want. Light years ahead of Bash's mess. Quoting is pretty easy to get right in Python.
Not a good argument imo. It eliminates a good class of problems sure. But you can’t eliminate their dependence on shared libraries that many commands also use, and that’s what my point was about.
And I’m sure you can find a whole dictionary’s worth of cases where people shoot themselves in the foot with bash. I don’t deny that’s the case. Bash is not a good language where the programmer is guarded from shooting themselves in the foot as much as possible. The guardrails are loose, and it’s the script writer’s job to guard themselves against it. Is that good for an enterprise scenario, where you may either blow something up, drop a database table, lead to the lost of lives or jobs, etc? Absolutely not. Just want to copy some files around and maybe send it to an internal chat for regular reporting? I don’t see why not.
Bash is not your hammer to hit every possible nail out there. That’s not what I’m proposing at all.
And I certainly am not proposing that we can abandon robustness.
If you're proposing Bash, then yes you are.
You’ll probably hate this, but you can use set -u to catch unassigned variables.
I actually didn't know that, thanks for the hint! I am forced to use Bash occasionally due to misguided coworkers so this will help at least.
But you can’t eliminate their dependence on shared libraries that many commands also use, and that’s what my point was about.
Not sure what you mean here?
Just want to copy some files around and maybe send it to an internal chat for regular reporting? I don’t see why not.
Well if it's just for a temporary hack and it doesn't matter if it breaks then it's probably fine. Not really what is implied by "production" though.
Also even in that situation I wouldn't use it for two reasons:
- "Temporary small script" tends to smoothly morph into "10k line monstrosity that the entire system depends on" with no chance for rewrites. It's best to start in a language that can cope with it.
- It isn't really any nicer to use Bash over something like Deno. Like... I don't know why you ever would, given the choice. When you take bug fixing into account Bash is going to be slower and more painful.
- Quoting. Trust me you've got this wrong even with
I just don't think bash is good for maintaining the code, debugging, growing the code over time, adding automated tests, or exception handling
If you need anything that complex and that it’s critical for, say, customers, or people doing things directly for customers, you probably shouldn’t use bash. Anything that needs to grow? Definitely not bash. I’m not saying bash is what you should use if you want it to grow into, say, a web server, but that it’s good enough for small tasks that you don’t expect to grow in complexity.
it’s (bash) good enough for small tasks that you don’t expect to grow in complexity.
I don't think you'll get a lot of disagreement on that, here. As mention elsewhere, my team prefers bash for simple use cases (and as their bash-hating boss, I support and agree with how and when they use bash.)
But a bunch of us draw the line at database access.
Any database is going to throw a lot of weird shit at the bash script.
So, to me, a bash script has grown to unacceptable complexity on the first day that it accesses a database.
small tasks that you don’t expect to grow in complexity
On one conference I heard saying: "There is no such thing as temporary solution and there is no such thing as proof of concept". It's an overexaguration of course but it has some truth to it - there's a high chance that your "small change" or PoC will be used for the next 20 years so write it as robust and resilient as possible and document it. In other words everything will be extended, everything will be maintained, everything will change hands.
So to your point - is bash production ready? Well, depends. Do you have it in git? Is it part of some automation pipeline? Is it properly documented? Do you by chance have some tests for it? Then yes, it's production ready.
If you just "write this quick script and run it in cron" then no. Because in 10 years people will pull their hair screaming "what the hell is hapenning?!"
Edit: or worse, they'll scream it during the next incident that'll happen at 2 AM on Sunday
"Use the best tool for the job, that the person doing the job is best at." That's my approach.
I will use bash or python dart or whatever the project uses.
Over the last ten - fifteen years, I've written lots of scripts for production in bash. They've all served their purposes (after thorough testing) and not failed. Pretty sure one of my oldest (and biggest) is called
temporary_fixes.shand is still in use today. Another one (admittedly not in production) was partially responsible for getting me my current job, I guess because the interviewers wanted to see what kind of person would solve a coding challenge in bash.However, I would generally agree that - while bash is good for many things and perhaps even "good enough" - any moderately complex problem is probably better solved using a different language.
As I've matured in my career, I write more and more bash. It is absolutely appropriate for production in the right scenarios. Just make sure the people who might have to maintain it in the future won't come knocking down your door with torches and pitchforks...
That’s my take on the use of bash too. If it’s something that people think it’s worth bring their pitchforks out for, then it’s something you should probably not write in bash.
At the level you're describing it's fine. Preferably use shellcheck and
set -euo pipefailto make it more normal.But once I have any of:
- nested control structures, or
- multiple functions, or
- have to think about handling anything else than simple strings that other programs manipulate (including thinking about bash arrays or IFS), or
- bash scoping,
- producing my own formatted logs at different log levels,
I'm on to Python or something else. It's better to get off bash before you have to juggle complexity in it.
Set don't forget set -E as well to exit on failed subshells.
If you're writing a lot of shell scripts and checking them with Shellcheck, and you're still convinced that it's totally safe... I tip my hat to you.
-e is great until there's a command that you want to allow to fail in some scenario.
I know OP is talking about bash specifically but pipefail isn't portable and I'm not always on a system with bash installed.
-e is great until there’s a command that you want to allow to fail in some scenario.
Yeah, I sometimes do
set +e do_stuff set -eIt's sort of the bash equivalent of a
try { do_stuff() } catch { /* intentionally bare catch for any exception and error */ /* usually a noop, but you could try some stuff with if and $? */ }I know OP is talking about bash specifically but pipefail isn’t portable and I’m not always on a system with bash installed.
Yeah, I'm happy I don't really have to deal with that. My worst-case is having to ship to some developer machines running macos which has bash from the stone ages, but I can still do stuff like rely on
[[rather than have to deal with[. I don't have a particular fondness for usingbashas anything but a sort of config file (withexport SETTING1=...etc) and some light handling of other applications, but I have even less fondness for POSIXsh. At that point I'm liable to rewrite it in Python, or if that's not availaible in a user-friendly manner either, build a small static binary.
A few responses for you:
- I deeply despise
bash(edit: this was hyperbole. I also deeply appreciate bash, as is appropriate for something that has made my life better for free!). That Linux shell defaults settled on it is an embarrassment to the entire open source community. (Edit: but Lexers and Parsers are hard! You don't see me fixing it, so yes, I'll give it a break. I still have to be discerning for production use, of course.) - Yes, Bash is good enough for production. It is the world's current default shell. As long as we avoid it's fancier features (which all suck for production use), a quick bash script is often the most reasonable choice.
- For the love of all that is holy, put your own personal phone number and no one else's in the script, if you choose to use
bashto access a datatbase. There's thousands of routine ways that database access can hiccup, and bash is suitable to help you diagnose approximately 0% of them. - If I found out a colleague had used bash for database access in a context that I would be expected to co-maintain, I would start by plotting their demise, and then talk myself down to having a severe conversation with them - after I changed it immediately to something else, in production, ignoring all change protocols. (Invoking emergency change protocols.)
Edit: I can't even respond to the security concerns aspect of this. Choice of security tool affects the quality of protection. In this unfortunate analogy, Bash is "the pull out method". Don't do that anywhere that it matters, or anywhere that one can be fired for security violations.
(Edit 2: Others have mentioned invoking SQL DB cleanup scripts from bash. I have no problem with that. Letting bash or cron tell the DB and a static bit of SQL to do their usual thing has been fine for me, as well. The nightmare scenario I was imagining was
bashgathering various inputs to the SQL and then invoking them. I've had that pattern blow up in my face, and had a devil of a time putting together what went wrong. It also comes with security concerns, as bash is normally a completely trusted running environment, and database input often come from untrusted sources.)Why internet man hate Bash? Bash do many thing. Make computer work.
I actually (also) love
bash, and use it like crazy.What I really hate is that
bashis so locked in legacy that it's bad features (on a scripting language scale, which isn't fair) (and of which there are too many to enumerate) are now locked in permanently.I also hate how convention has kept other shells from replacing bash's worst features with better modern alternatives.
To some extent, I'm railing against how hard it is to write a good Lexer and a Parser, honestly. Now that bash is stable, there's little interest in improving it. Particularly since one can just invoke a better scripting language for complex work.
I mourn the sweet spot that Perl occupies, that Bash and Python sit on either side of, looking longingly across the gap that separated their practical use cases.
I have lost hope that Python will achieve shell script levels of pragmatism. Although the
invokelibrary is a frigging cool attempt.But I hold on to my sorrow and anger that Bash hasn't bridged the gap, and never will, because whatever it can invoke, it's methods of responding to that invocation are trapped in messes like "if...fi".
Could you explain those db connection hiccups you’ve seen?
Sure.
I'll pick on
postgresbecause it's popular. But I have found that most databases have a similar number of error codes.https://www.postgresql.org/docs/current/errcodes-appendix.html
It's not an specific error that's the issue, it's the sheer variety of ways things can go wrong, combined with bash not having been architected with the database access use case in mind.
- I deeply despise
Wanna check if a variable’s set to something expected?
if [[ <test goes here> ]]; then <handle>; fiHey, you can't just leave out "test goes here". That's worst part by a long shot.
The rest of the syntax, I will have to look up every time I try to write it, but at least I can mostly guess what it does when reading. The test syntax on the other hand is just impossible to read without looking it up.I also don't actually know how to look that up for the double brackets, so that's fun. For the single bracket, it took me years to learn that that's actually a command and you can do
man [to view the documentation.To be fair, you don’t always have to use the
[[syntax. I know I don’t, e.g. if I’m just looking for a command that returns 1 or 0, which happens quite a bit if you get to usegrep.That said,
man testis my friend.But I’ve also gotten so used to using it that I remember
-zand-nby heart :PIf you need to use bash a lot just to learn 2 "keywords", then it's not a good language.
I have looked at bash scripts in the past, and even written some (small amount). I had to look up
-zand-nevery time. I've written a lot more python than bash, that's for sure. But even if I don't write python for a year, when needed I can just write an entire python script without minimal doc lookups. I just need to search if the function I want is part ofsyd,osorpath.The first time I want to do an
else ifmy IDE will mark it red and I'll writeeliffrom then on, same thing if I try to use{}.If a bash script requires at least one array and one if statement, I can write the entire thing in python faster than I can search how to do those 2 things in bash.
Well then you guys will love what this guy (by tha name "icitry") did with bash https://www.youtube.com/watch?v=b_WGoPaNPMY
He created a youtube clone with Bash
That is definitely not something I would do… for work (totally not implying that I miiiight do it outside of work for shits and giggles :P).
I didn’t create this post trying to be like “y’all should just use Bash”, nor is it an attempt to say that I like Bash, but I guess that’s how people boil others down to these days. Fanatics only. Normalcy is dead. (I’m exaggerating ofc)
Basically, If you are crazy enough, you csn make anything with any language<br> Hence, me sharing the video
It's ok for very small scripts that are easy to reason through. I've used it extensively in CI/CD, just because we were using Jenkins for that and it was the path of least resistance. I do not like the language though.
I don't disagree with this, and honestly I would probably support just using bash like you said if I was in a team where this was suggested.
I think no matter how simple a task is there are always a few things people will eventually want to do with it:
- Reproduce it locally
- Run unit tests, integration tests, smoke tests, whatever tests
- Expand it to do more complex things or make it more dynamic
- Monitor it in tools like Datadog
If you have a whole project already written in Python, Go, Rust, Java, etc, then just writing more code in this project might be simpler, because all the tooling and methodology is already integrated. A script might not be so present for many developers who focus more on the code base, and as such out of sight out of mind sets in, and no one even knows about the script.
There is also the consideration that many people simply dislike bash since it's an odd language and many feel it's difficult to do simple things with it.
due to these reasons, although I would agree with making the script, I would also be inclined to have the script temporarily while another solution is being implemented.
I don’t necessarily agree that all simple tasks will lead to the need for a test suite to accommodate more complex requirements. If it does reach that point,
- Your simple bash script has and is already providing basic value.
- You can (and should) move onto a more robust language to do more complicated things and bring in a test suite, all while you have something functional and delivering value.
I also don’t agree that you can just solder on whatever small task you have to whatever systems you already have up and running. That’s how you make a Frankenstein. Someone at some point will have to come do something about your little section because it started breaking, or causing other things to break. It could be throwing error messages because somebody changed the underlying db schema. It could be calling and retrying a network call and due to, perhaps, poorly configured backoff strategy, you’re tripping up monitoring alerts.
That said, I do agree on it suitable for temporary tasks.
Bash is perfectly good for what you’re describing.
Serious question (as a bash complainer):
Have I missed an amazing bash library for secure database access that justifies a "perfectly good" here?
Run checkbashisms over your $PATH (grep for #!/bin/sh). That's the problem with Bash.
#!/bin/shis for POSIX compliant shell scripts only, use#!/bin/bashif you use bash syntax.Btw, i quite like yash.
Always welcome a new shell. I’ve not heard of yash but I’ll check it out.
Any reason to use
#!/bin/shover#!/usr/bin/env sh?#!/usr/bin/env sh
You want to use a
/usr/bincommand to find a/bincommand?Do you know why
/usr/binand/binaren't the same, and why you should never rely on a/usr/{s,}binwhere you'd be selecting for a/{s,}bincommand? (and how, in trying to eradicate/usr, Lennart proved his reach exceeded his grasp?)
Dude, pihole is bash.
I'm fine with bash for ci/cd activities, for what you're talking about I'd maybe use bash to control/schedule running of a script in something like python to query and push to an api but I do totally get using the tools you have available.
I use bash a lot for automation but PowerShell is really nice for tasks like this and has been available in linux for a while. Seen it deployed into production for more or less this task, grabbing data from a sql server table and passing to SharePoint. It's more powerful than a shell language probably needs to be, but it's legitimately one of the nicer products MS has done.
End of the day, use the right tool for the job at hand and be aware of risks. You can totally make web requests from sql server using ole automation procedures, set up a trigger to fire on update and send data to an api from a stored proc, if I recall there's a reason they're disabled by default (it's been a very long time) but you can do it.
People have really been singing praises of Powershell huh. I should give that a try some time.
But yeah, we wield tools that each come with their own risks and caveats, and none of them are perfect for everything, but some are easier (including writing it and addressing fallovers for it) to use in certain situations than others.
It’s just hard to tell if people’s fear/disdain/disgust/insert-negative-reaction towards bash is rational or more… tribal, and why I decided to ask. It’s hard to shake away the feeling of “this shouldn’t just be me, right?”
The nice thing about Powershell is that it was built basically now after learning all the things that previous shells left out. I'm not fluent in it, but as a Bash aficionado, I marveled at how nice it was at a previous job where we used it.
That said, I love Bash and use it for lots of fun automation. I think you're right to appreciate it as you do. I have no opinion on the rest.
In your own description you added a bunch of considerations, requirements of following specific practices, having specific knowledge, and a ton of environmental requirements.
For simple scripts or duck tape schedules all of that is fine. For anything else, I would be at least mindful if not skeptical of bash being a good tool for the job.
Bash is installed on all linux systems. I would not be very concerned about some dependencies like sqlite, if that is what you're using. But very concerned about others, like jq, which is an additional tool and requirement where you or others will eventually struggle with diffuse dependencies or managing a managed environment.
Even if you query sqlite or whatever tool with the command line query tool, you have to be aware that getting a value like that into bash means you lose a lot of typing and structure information. That's fine if you get only one or very few values. But I would have strong aversions when it goes beyond that.
You seem to be familiar with Bash syntax. But others may not be. It's not a simple syntax to get into and intuitively understand without mistakes. There's too many alternatives of if-ing and comparing values. It ends up as magic. In your example, if you read code, you may guess that
:-means fallback, but it's not necessarily obvious. And certainly not other magic flags and operators.
As an anecdote, I guess the most complex thing I have done with Bash was scripting a deployment and starting test-runs onto a distributed system (and I think collecting results? I don't remember). Bash was available and copying and starting processes via ssh was simple and robust enough. Notably, the scope and env requirements were very limited.
You seem to be familiar with Bash syntax. But others may not be.
If by this you mean that the Bash syntax for doing certain things is horrible and that it could be expressed more clearly in something else, then yes, I agree, otherwise I'm not sure this is a problem on the same level as others.
OP could pick any language and have the same problem. Except maybe Python, but even that strays into symbolic line noise once a project gets big enough.
Either way, comments can be helpful when strange constructs are used. There are comments in my own Bash scripts that say what a line is doing rather than just why precisely because of this.
But I think the main issue with Bash (and maybe other shells), is that it's parsed and run line by line. There's nothing like a full script syntax check before the script is run, which most other languages provide as a bare minimum.
OP could pick any language and have the same problem. Except maybe Python, but even that strays into symbolic line noise once a project gets big enough.
Personally, I don't see python far off from bash. Decent for small scripts, bad for anything bigger. While not necessarily natively available, it's readily available and more portable (Windows), and has a rich library ecosystem.
Personally, I dislike the indent syntax. And the various tooling and complexities don't feel approachable or stable, and structuring not good.
But maybe that's me. Many people seem to enjoy or reach for python even for complex systems.
More structured and stable programming languages do not have these issues.
As one other comment mentioned, unfamiliarity with a particular language isn’t restricted to just bash. I could say the same for someone who only dabbles in C being made to read through Python. What’s this
@decoratorthing? Or what’sf"Some string: {variable}"supposed to do, and how’s memory being allocated here? It’s a domain, and we aren’t expected to know every single domain out there.And your mention of losing typing and structure information is… ehh… somewhat of a weird argument. There are many cases where you don’t care about the contents of an output and only care about the process of spitting out that output being a success or failure, and that’s bread and butter in shell scripts. Need to move some files, either locally or over a network, bash is good for most cases. If you do need something just a teeny bit more, like whether some key string or pattern exists in the output, there’s grep. Need to do basic string replacements? sed or awk. Of course, all that depends on how familiar you or your teammates are with each of those tools. If nearly half the team are not, stop using bash right there and write it in something else the team’s familiar with, no questions there.
This is somewhat of an aside, but jq is actually pretty well-known and rather heavily relied upon at this point. Not to the point of say sqlite, but definitely more than, say, grep alternatives like ripgrep. I’ve seen it used quite often in deployment scripts, especially when interfaced with some system that replies with a json output, which seems like an increasingly common data format that’s available in shell scripting.
Yes, every unfamiliar language requires some learning. But I don't think the bash syntax is particularly approachable.
I searched and picked the first result, but this seems to present what I mean pretty well https://unix.stackexchange.com/questions/248164/bash-if-syntax-confusion which doesn't even include the alternative if parens https://stackoverflow.com/questions/12765340/difference-between-parentheses-and-brackets-in-bash-conditionals
I find other languages syntaxes much more approachable.
I also mentioned the magic variable expansion operators. https://www.gnu.org/software/bash/manual/html_node/Shell-Parameter-Expansion.html
Most other languages are more expressive.
I've only ever used bash.
May I introduce you to rust script? Basically a wrapper to run rust scripts right from the command line. They can access the rust stdlib, crates, and so on, plus do error handling and much more.
Yeah, sometimes I'll use that just to have the sane control flow of Rust, while still performing most tasks via commands.
You can throw down a function like this to reduce the boilerplate for calling commands:
fn run(command: &str) { let status = Command::new("sh") .arg("-c") .arg(command) .status() .unwrap(); assert!(status.success()); }Then you can just write
run("echo 'hello world' > test.txt");to run your command.Defining
runis definitely the quick way to do it 👍 I'd love to have a proc macro that takes a bash like syntax e.gsomeCommand | readsStdin | processesStdIn > someFileand builds the necessary rust to use. xonsh does it using a superset of python, but I never really got into it.
Basically a wrapper to run rust scripts right from the command line.
Isn't that just Python? :v
How easily can you start parsing arguments and read env vars? Do people import clap and such to provide support for those sorts of needs?
I'd use clap, yeah. And env vars
std::env::var("MY_VAR")?You can of course start writing your own macro crate. I wouldn't be surprised if someone already did write a proc macro crate that introduces its own syntax to make calling subprocesses easier. The shell is.. your oyster 😜
Pretty much all languages are middleware, and most of the original code was shell/bash. All new employees in platform/devops want to immediately push their preferred language, they want java and rust environments. It's a pretty safe bet if they insist on using a specific language; then they don't know how awk or sed. Bash has all the tools you need, but good developers understand you write libraries for functionality that's missing. Modern languages like Python have been widely adopted and has a friendlier onboarding and will save you time though.
Saw this guy's post in another thread, he's strawmanning because of lack of knowledge.
Pretty much all languages are middleware, and most of the original code was shell/bash.
What? I genuinely do not know what you mean by this.
2 parts:
- All languages are middleware. Unless you write in assembly, whatever you write isn't directly being executed, they are being run through a compiler and being translated from your "middle language" or into 0s and 1s the computer can understand. Middleware is code used in between libraries to duplicate their functionality.
https://azure.microsoft.com/en-us/resources/cloud-computing-dictionary/what-is-middleware/ - Most original code was written in shell. Most scripting is done in the cli or shell language and stored as a
script.shfile, containing instructions to execute tasks. Before python was invented you used the basic shell because nothing else existed yet
- All languages are middleware. Unless you write in assembly, whatever you write isn't directly being executed, they are being run through a compiler and being translated from your "middle language" or into 0s and 1s the computer can understand. Middleware is code used in between libraries to duplicate their functionality.
Can I slap a decorator on a Bash function? I love my
@retry(...)(viatenacity, even if it's a bit wordy).I’m going to read this with a big “/s” at the end there xD