What do you advice for shell usage?
- Do you use bash? If not, which one do you use? zsh, fish? Why do you do it?
- Do you write
or
? Do you write fish exclusive scripts?
- Do you have two folders, one for proven commands and one for experimental?
- Do you publish/ share those commands?
- Do you sync the folder between your server and your workstation?
- What should’ve people told you what to do/ use?
- good practice?
- general advice?
- is it bad practice to create a handful of commands like
podup
andpoddown
that replacepodman compose up -d
andpodman compose down
orpodlog
aspodman logs -f --tail 20 $1
orpodenter
forpodman exec -it "$1" /bin/sh
?
Background
I started bookmarking every somewhat useful website. Whenever I search for something for a second time, it’ll popup as the first search result. I often search for the same linux commands as well. When I moved to atomic Fedora, I had to search for rpm-ostree
(POV: it was a horrible command for me, as a new user, to remember) or sudo ostree admin pin 0
. Usually, I bookmark the website and can get back to it. One day, I started putting everything into a .bashrc
file. Sooner rather than later I discovered that I could simply add ~/bin
to my $PATH
variable and put many useful scripts or commands into it.
For the most part I simply used bash. I knew that you could somehow extend it but I never did. Recently, I switched to fish because it has tab completion. It is awesome and I should’ve had completion years ago. This is a game changer for me.
I hated that bash would write the whole path and I was annoyed by it. I added PS1="$ "
to my ~/.bashrc
file. When I need to know the path, I simply type pwd
. Recently, I found starship which has themes and adds another line just for the path. It colorizes the output and highlights whenever I’m in a toolbox/distrobox. It is awesome.
#!/usr/bin/env bash
A folder
dotfiles
as git repository and adotfiles/install
that soft links all configurations into their places.Two files,
~/.zshrc
(without secrets, could be shared) and another for secrets (sourced by.zshrc
if exist secrets).This is the way!
why?
because bash isn’t always in
/usr/bin/bash
.On macOS the version on
/usr/bin/bash
is very old (bash 3 I think?), so many users install a newer version with homebrew which ends up in PATH, which/usr/bin/env
looks at.Protip: I start every bash script with the following two lines:
#!/usr/bin/env bash set -euo pipefail
set -e makes the script exit if any command (that’s not part of things like if-statements) exits with a non-zero exit code
set -u makes the script exit when it tries to use undefined variables
set -o pipefail will make the exit code of the pipeline have the rightmost non-zero exit status of the pipeline, instead of always the rightmost command.
Nice, thx!
/bin/sh
is always/bin/sh
.
!/usr/bin/env
will look inPATH
forbash
, andbash
is not always in/bin
, particularly on non-Linux systems. For example, on OpenBSD it’s in /usr/local/bin, as it’s an optional package.If you are sure
bash
is in/bin
and this won’t change, there’s no harm in putting it directly in your shebang.
dotfiles
Thanks! I’ll check them out. I knew the cooncept existed but so far I didn’t dig deep into managing them. This is my start I guess https://wiki.archlinux.org/title/Dotfiles
Instead of a install skript, check out GNU stow. It does exactly that and you can interqctively choose which things to install/symlink.
Use
shellcheck
I use Bash for scripts, though my interactive shell is Fish.
Usually I use
as shebang. This has the advantage of searching your PATH for Bash instead of hardcoding it.
My folders are only differentiated by those in my PATH and those not.
Most of my scripts can be found here. They are purely desktop use, no syncing to any servers. Most would be useless there.
For good practice, I’d recommend using
set -euo pipefail
to make Bash slightly less insane and use shellcheck to check for issues.
This is personal preference, but you could avoid Bashisms like [[ and stick to POSIX sh. (Usethen.)
With shortened commands the risk is that you might forget how the full command works. How reliant you want to be on those commands being present is up to you. I wouldn’t implement them as scripts though, just simple aliases instead.
Scripts only make sense if you want to do something slightly more complex over multiple lines for readability.#/usr/bin/env bash typo?
thx for the tips!
I prefer single files over aliases since I can more easily manage each command.
You’re right, it’s
#!
Use
set -x
For debugging
Good to know!
Several things
- write bash and nothing else (except posix sh)
- find a good way to take notes. It shouldn’t be in your bashrc
- only write fish for fish config
- use $!/usr/bin/env bash
Good idea I added a “iwish” command a while ago. Whenever I am pissed about gnome not being able to do something, or anything else that didn’t work as it should, I wrote “iwish gnome had only one extension app” and it would add a new line to my wishlist.md Maybe it would be good for notes too.
inote bla
I love thay idea im gonna implement it tonight
That’s the way I do it:
#!/usr/bin/env nix #! nix shell nixpkgs#nushell <optionally more dependencies> --command nu <script content>
But those scripts are only used by me
I use bash as my interactive shell. When ~20 years ago or so I encountered “smart” tab completion for the first time, I immediately disabled that and went back to dumb completion, because it caused multi-second freezes when it needed to load stuff from disk. I also saw it refuse to complete filenames because they had the wrong suffix. Maybe I should try to enable that again, see if it works any better now. It probably does go faster now with the SSDs.
I tried OpenBSD at some point, and it came with some version of ksh. Seems about equivalent to bash, but I had to modify some of my .bashrc so it would work on ksh. I would just stick to the default shell, whatever it is, it’s fine.
I try to stick to POSIX shell for scripts. I find that I don’t need bashisms very often, and I’ve used systems without bash on them. Most bash-only syntax has an equivalent that will work on POSIX sh. I do use bash if I really need some bash feature (I recently wanted to
set -o pipefail
, which dash cannot do apparently, and the workaround is really annoying).Do not use
if you’re writing bash-only scripts. This will break on Debian, Ubuntu, BSD, busybox etc. because /bin/sh is not bash on those systems.
Do not use #!/bin/sh if you’re not writing bash-only scripts
Actually
is for bourne shell compatible scripts. Bash is a superset of the bourne shell, so anything that works in bourne should work in bash as well as in other bourne compatible shells, but not vice versa. Bash specific syntax is often referred to as a “bashism”, because it’s not compatible with other shells. So you should not use bashisms in scripts that start with
.
The trouble is that it is very common for distros to links
/bin/sh
to/bin/bash
, and it used to be that bash being called as/bin/sh
would change its behavior so that bashisms would not work, but this doesn’t appear to be the case anymore. The result is that people often write what they think are bourne shell scripts but they unintentionally sneak in bashisms… and then when those supposed “bourne shell” scripts get run on a non-bash bourne compatible shell, they fail.Oh I wanted to say, “Do not use
if you’re
notwriting bash-only scripts”. I think I reformulated that sentence and forgot to remove the not. Sorry about the confusion. You’re exactly right of course. I have run into scripts that don’t work on Debian, because the author used bashisms but still specified /bin/sh as the interpreter.Oh I wanted to say, “Do not use #!/bin/sh if you’re not writing bash-only scripts”
Hah, I was wondering if that was wat you actually meant. The double negation made my head spin a bit.
I have run into scripts that don’t work on Debian, because the author used bashisms but still specified /bin/sh as the interpreter.
The weird thing is that
man bash
still says:When invoked as sh, bash enters posix mode after the startup files are read. ... --posix Change the behavior of bash where the default operation differs from the POSIX standard to match the standard (posix mode). See SEE ALSO below for a reference to a document that details how posix mode affects bash's behavior.
But if you create a file with a few well known bashisms, and a
shebang, it runs the bashisms just fine.
I primarily operate in strict standard compliance mode where I write against the shell specifications in the lastest Single Unix Specification and do not use a she-bang line since including one results in unspecified, implementation-defined behavior. Generally people seem to find this weird and annoying.
Sometimes I embrace using bash as a scripting language, and use one of the env-based she-bangs. In that case, I go whole-hog on bashisns. While I use zsh as my interactive shell, even I’m not mad enough to try to use it for scripts that need to run in more than one context (like other personal accounts/machines, even).
In ALL cases, use shellcheck and at least understand the diagnostics reported, even if you opt not to fix them. (I generally modify the script until I get a clean shellcheck run, but that can be quite involved… lists of files are pretty hard to deal with safely, actually.)
Do you use bash? If not, which one do you use? zsh, fish? Why do you do it?
Mostly fish, because it just feels much more modern than bash, it has good built-in autocomplete and I don’t have to install millions of plugins like of zsh.
Do you write #!/bin/bash or #!/bin/sh? Do you write fish exclusive scripts?
Occasionally I also write fish scripts. Just replace sh with fish.
What should’ve people told you what to do/ use?
general advice?
As @crispy_kilt@feddit.de already suggested, use shellcheck.
is it bad practice to create a handful of commands like podup and poddown that replace podman compose up -d and podman compose down or podlog as podman logs -f --tail 20 $1 or podenter for podman exec -it “$1” /bin/sh?
I don’t think so
- Fish. Much, much saner defaults.
- I am writing
for dead simple scripts, so they will be a tiny bit more portable and run a tiny bit faster. The lack of arrays causes too much pain in longer scripts. I would love to use Fish, but it lacks a strict mode.
- No, why would I?
- I used to share all my dotfiles, scripts included, but I was too afraid that I would publish some secrets someday, so I stopped doing that. For synchronizing commands, aliases and other stuff between computers I use Chezmoi.
- To use Fish instead of fighting with start up time of Zsh with hundreds of plugins
- Always use the so-called “strict mode” in Bash, that is, the
set -euo pipefail
line. It will make Bash error on non-zero exit code, undefined variables and non-zero exit codes in commands in pipe. Also, always use shellcheck. It’s extremely easy to make a mistake in Bash. If you want to check the single command exit code manually, just wrap it inset +e
andset -e
. - Consider writing your scripts in Python. Like Bash, it also has some warts, but is multiplatform and easy to read. I have a snippet which contains some boilerplate like a
main
function definition withArgumentParser
instantiated. Then at the end of the script themain
function is called wrapped intry … except KeyboardInterrupt: exit(130)
which should be a default behavior. - Absolutely not a bad practice. If you need to use them on a remote server and can’t remember what they stand for, you can always execute
type some_command
. Oh, and read about abbreviations in Fish. It always expands the abbreviation, so you see what you execute.
- I usually use bash/python/perl if I can be sure that it will be available on all systems I intend to run the scripts. A notable exception for this would be alpine based containers, there it’s nearly exclusively
.
- Depending on the complexity I will either have a git repository for all random scripts I need and not test them, or a single repo per script with Integrationtests.
- Depends, if they are specific to my setup, no, otherwise the git repository is public on my git server.
- Usually no, because the servers are not always under my direct control, so the scripts that are on servers are specific to that server/the server fleet.
- Regarding your last question in the list: You do you, I personally don’t, partly because of my previous point. A lot of servers are “cattle” provisioned and destroyed on a whim. I would have to sync those modifications to all machines to effectively use them, which is not always possible. So I also don’t do this on any personal devices, because I don’t want to build muscle memory that doesn’t apply everywhere.
- I usually use bash/python/perl if I can be sure that it will be available on all systems I intend to run the scripts. A notable exception for this would be alpine based containers, there it’s nearly exclusively
A good idea i have been spreading around relevant people lately is to use ShellCheck as you code in Bash, integrate it in your workflow, editor or IDE as relevant to you (there’s a commandline tool as well as being available for editors in various forms), and pass your scripts through it, trying to get the warnings to go away. That should fix many obvious errors and clean up your code a bit.
I use fish shell only now. Used to only write bash, but I’ve started writing some fish scripts. I wouldn’t try to plan too much WRT shell scripting up front. Just fix your pain points as you go.
I use
sh
to attempt to keep it compatible with POSIX systems.I use pain bash. Never really tried zsh and fish, since most of my Linux work is on servers and I don’t really care for extra features.
I try and write idempotent scripts when possible.
I wouldn’t create those aliases on a fleet because writing them to the configuration file of your shell in an idempotent fashion is hacky and my VMs are like cattle.
You are way over thinking it.