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-urlencoded
request 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.curl
already does all that. - Need to read from a
curl
response and it’s JSON? Reach forjq
. - Instead of having to set up a connection object/instance to your database, give
sqlite
,psql
,duckdb
or 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
Ubuntu
ordebian
oralpine
, 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?
Can I slap a decorator on a Bash function? I love my
(via
tenacity
, even if it’s a bit wordy).I’m going to read this with a big “/s” at the end there xD
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.
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.
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
@decorator
thing? 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.
Your experiences are based on your familiarity with other languages. It may or may not apply to others. So to each their own I guess?
I do agree that the square bracket situation is not best though. But once you know it, you, well, know it. There’s also shellcheck to warn you of gotchas. Not the best to write in, but we have linters in most modern languages for a reason.
I actually like bash’s variable expansion. It’s very succinct (so easier to write and move onto your next thing) and handles many common cases. The handling is what I hope most stdlibs in languages would do with env vars by default, instead of having to write a whole function to do that handling. Falling back is very very commonly used in my experience.
There are cases where programming is an exercise of building something. Other times, it’s a language, and when we speak, we don’t necessarily want to think too much about syntax or grammar, and we’d even invent syntaxes to make what we have to say shorter and easier to say, so that we may speak at the speed of thought.
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.
At the level you’re describing it’s fine. Preferably use shellcheck and
set -euo pipefail
to 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.
-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 -e
It’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 usingbash
as 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.It’s nice to agree with someone on the Internet for once :)
Have a great day!
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.
“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.
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.
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.sh
file, containing instructions to execute tasks. Before python was invented you used the basic shell because nothing else existed yet
The first part is confusing what “middleware” means. Rather than “duplicating” functionality, it connects libraries (I’m guessing this is what you meant). But that has nothing to do with a language being compiled versus “directly executed”, because compilation doesn’t connect different services or libraries; it just transforms a higher-level description of execution into an executable binary. You could argue that an interpreter or managed runtime is a form of “middleware” between interpreted code and the operating system, but middleware typically doesn’t describe anything so critical to a piece of software that the software can’t run without it, so even that isn’t really a correct use of the term.
The second part is just…completely wrong. Lisp, Fortran, and other high-level languages predate terminal shells; C obviously predates the shell because most shells are written in C. “Most original code” is in an actual systems language like C.
(As a side note, Python wasn’t the first scripting language, and it didn’t become popular very quickly. Perl and Tcl preceded it; Lua, php, and R were invented later but grew in popularity much earlier.)
- 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.
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.
Wanna check if a variable’s set to something expected?
if [[ <test goes here> ]]; then <handle>; fi
Hey, 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 test
is my friend.But I’ve also gotten so used to using it that I remember
-z
and-n
by 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
-z
and-n
every 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
,os
orpath
.The first time I want to do an
else if
my IDE will mark it red and I’ll writeelif
from 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.
To each their own really. You have what you’re familiar with, and I have mine. That said, I’m not proposing Bash as a good language. It is by no means that.
Now, to use Python for comparison. With a year of not using it, I’d be asking lots of questions. How do I
mkdir
? How do Imkdir -p
? What aboutcp
ormv
and their flags? Did I use to bring in some library to make this less painful?Cause look, I already use many of these commands in the terminal, basically all the time cause I work in it.
Fwiw, there’s a
bash-language-server
that can warn you of some syntactical errors.
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.
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 😜I can only imagine that macro crate being a nightmare to read and maintain given how macros are still insanely hard to debug last I heard (might be a few years ago now).
proc macros can be called in tests and debugged. They aren’t that horrible, but can be tedious to work with. A good IDE makes it a lot easier though, that’s for sure.
Check out @[email protected]’s comment with existing libraries. Someone already did the work! 🎉
I’m so glad we have madlads in rust land xD Thanks for referring me to that!
Basically a wrapper to run rust scripts right from the command line.
Isn’t that just Python? :v
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
run
is 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 > someFile
and builds the necessary rust to use. xonsh does it using a superset of python, but I never really got into it.Wow, that’s exactly what I was looking for! Thanks dude.
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] = …
I use the same heuristic… if I need a hashmap or more complex math, I need a different language
Also if the script grows beyond 100 lines, I stop and think about what I’m doing. Sometimes it’s OK, but it’s a warning flag
Yeah agreed on the 100 lines, or some other heuristic in the direction of “this script will likely continue to grow in complexity and I should switch to a language that’s better suited to handle that complexity”.
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.
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?
Every database I know comes with an SQL shell that takes commands from stdin and writes query results to stdout. Remember that “bash” never means bash alone, but all the command line tools from cut via jq to awk and beyond … so, that SQL shell would be what you call “bash library”.
Thank you. I wasn’t thinking about that. That’s a great point.
As long as any complex recovery logic fits inside the SQL, itself, I don’t have any issue invoking it from
bash
.It’s when there’s complicated follow-up that needs to happen in bash that I get anxious about it, due to past painful experiences.
Right, that’s when you should look for a driver language that’s better suited for the job, e. g. Python.
I’ve only ever used 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
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 ofpipefail
noise. 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$1
No. If it’s missing
$1
will 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.
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
shellcheck
andbash-language-server
that 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
$1
will 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 -u
to 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.
I’m going to downvote your comment based on that first quote reply, because I think that’s an extreme take that’s unwarranted. You’ve essentially dissed people who use it for CI/CD and suggested that their pipeline is not robust because of their choice of using Bash at all.
And judging by your second comment, I can see that you have very strong opinions against bash for reasons that I don’t find convincing, other than what seems to me like irrational hatred from being rather uninformed. It’s fine being uninformed, but I suggest you tame your opinions and expectations with that.
About shared libraries, many popular languages, Python being a pretty good example, do rely on these to get performance that would be really hard to get from their own interpreters / compilers, or if re-implementing it in the language would be pretty pointless given the existence of a shared library, which would be much better scrutinized, is audited, and is battle-tested. libcrypto is one example. Pandas depends on NumPy, which depends on, I believe, libblas and liblapack, both written in C, and I think one if not both of these offer a cli to get answers as well. libssh is depended upon by many programming languages with an ssh library (though there are also people who choose to implement their own libssh in their language of choice). Any vulnerabilities found in these shared libraries would affect all libraries that depend on them, regardless of the programming language you use.
If production only implies systems in a user’s path and not anything else about production data, then sure, my example is not production. That said though, I wouldn’t use bash for anything that’s in a user’s path. Those need to stay around, possible change frequently, and not go down. Bash is not your language for that and that’s fine. You’re attacking a strawman that you’ve constructed here though.
If your temporary small script morphs into a monster and you’re still using bash, bash isn’t at fault. You and your team are. You’ve all failed to anticipate that change and misunderstood the “temporary” nature of your script, and allowed your “temporary thing” to become permanent. That’s a management issue, not a language choice. You’ve moved that goalpost and failed to change your strategy to hit that goal.
You could use Deno, but then my point stands. You have to write a function to handle the case where an env var isn’t provided, that’s boilerplate. You have to get a library for, say, accessing contents in Azure or AWS, set that up, figure out how that api works, etc, while you could already do that with the awscli and probably already did it to check if you could get what you want. What’s the syntax for
mkdir
? What’s it formkdir -p
? What about other options? If you already use the terminal frequently, some of these are your basic bread and butter and you know them probably by heart. Unless you start doing that with Deno, you won’t reach the level of familiarity you can get with the shell (whichever shell you use ofc).And many argue against bash with regards to error handling. You don’t always need something that proper language has. You don’t always need to handle every possible error state differently, assuming you have multiple. Did it fail? Can you tolerate that failure? Yup? Good. No? Can you do something else to get what you want or make it tolerable? Yes? Good. No? Maybe you don’t want to use bash then.
You’ve essentially dissed people who use it for CI/CD and suggested that their pipeline is not robust because of their choice of using Bash at all.
Yes, because that is precisely the case. It’s not a personal attack, it’s just a fact that Bash is not robust.
You’re trying to argue that your cardboard bridge is perfectly robust and then getting offended that I don’t think you should let people drive over it.
About shared libraries, many popular languages, Python being a pretty good example, do rely on these to get performance that would be really hard to get from their own interpreters / compilers, or if re-implementing it in the language would be pretty pointless given the existence of a shared library, which would be much better scrutinized, is audited, and is battle-tested. libcrypto is one example. Pandas depends on NumPy, which depends on, I believe, libblas and liblapack, both written in C, and I think one if not both of these offer a cli to get answers as well. libssh is depended upon by many programming languages with an ssh library (though there are also people who choose to implement their own libssh in their language of choice). Any vulnerabilities found in these shared libraries would affect all libraries that depend on them, regardless of the programming language you use.
You mean “third party libraries” not “shared libraries”. But anyway, so what? I don’t see what that has to do with this conversation. Do your Bash scripts not use third party code? You can’t do a lot with pure Bash.
If your temporary small script morphs into a monster and you’re still using bash, bash isn’t at fault. You and your team are.
Well that’s why I don’t use Bash. I’m not blaming it for existing, I’m just saying it’s shit so I don’t use it.
You could use Deno, but then my point stands. You have to write a function to handle the case where an env var isn’t provided, that’s boilerplate.
Handling errors correctly is slightly more code (“boilerplate”) than letting everything break when something unexpected happens. I hope you aren’t trying to use that as a reason not to handle errors properly. In any case the extra boilerplate is…
Deno.env.get("FOO")
. Wow.What’s the syntax for mkdir? What’s it for mkdir -p? What about other options?
await Deno.mkdir("foo"); await Deno.mkdir("foo", { recursive: true });
What’s the syntax for a dictionary in Bash? What about a list of lists of strings?
I don’t disagree with your point, but how does
set -e
break 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-code
orgrep
.I think I was actually thinking of
pipefail
though. If you don’t set it then errors in pipelines are ignored, which is obviously bad. If you do then you can’t usegrep
in pipelines.
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/sh
ends up spawning an interactive shell…So you can add up binaries insanity on top of bash’s mess.
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”.
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.
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
- Quoting. Trust me you’ve got this wrong even with
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?”
I have to wonder if some of it is comfort or familiarity, I had a negative reaction to python the first time I ever tried it for example, hated the indent syntax for whatever reason.
Creature comfort is a thing. You’re used to it. Familiarity. You know how something behaves when you interact with it. You feel… safe. Fuck that thing that I haven’t ever seen and don’t yet understand. I don’t wanna be there.
People who don’t just soak in that are said to be, maybe, adventurous?
It can also be a “Well, we’ve seen what can work. It ain’t perfect, but it’s pretty good. Now, is there something better we can do?”
The indent syntax is one of the obviously bad decisions in the design of python so it makes sense
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.