Bash variables: A subshell cannot write back variables to its parent shell.
I want to get a variable AA back anyway and tried:
1. in the subshell: declare -p AA >./tmp/somefile
2. in the parent shell: source ./tmp/somefile
Can this fail? Well (2) is run in a function, so the 'declare ...' we source only declares a local variable. As soon as leaving the function, the AA is gone.
There does not seem to be a version of 'declare -p' which adds "-g" to the output.
Struggling with shell script arguments? Our guide breaks down positional parameters step by step! From $0 to ${10}, we've got you covered with practical examples.
Read: Mastering Positional Parameters in Linux at: https://www.spsanderson.com/steveondata/posts/2025-04-18/
Tracing the #!: How the Linux Kernel Handles the Shebang - One of the delights in Bash, zsh, or whichever shell tickles your fancy in your OS... - https://hackaday.com/2025/04/11/tracing-the-how-the-linux-kernel-handles-the-shebang/ #linuxkernel #shellscript #linuxhacks
A 6502, In The Shell - Shell scripting is an often forgotten programming environment, relegated to simple... - https://hackaday.com/2025/03/17/a-6502-in-the-shell/ #microcontrollers #softwarehacks #shellscript #linuxhacks #shell
How To Replace Text In Multiple Files Using A Bash Script In Linux #Bash #ShellScript #Linux #Linuxcommands #Linuxhowto #Linuxbasics
https://ostechnix.com/replace-text-in-multiple-files-using-bash-script/
Linux Fu: Use the Source (Command), Luke - You can argue if bash is a good programming language or not, but you can’t argue t... - https://hackaday.com/2025/03/13/linux-fu-use-the-source-command-luke/ #hackadaycolumns #shellscript #linuxhacks #linux #bash
@jutty I sometimes *do* enjoy writing #shellscript. Kind of similar to how I sometimes even enjoy writing #Javascript.
First of all, I think the only sane way to write shell scripts is to aim for strict #POSIX compliance. Sure, if you write "internal" scripts for some OS or distribution, it's fine to target specifically the shell coming with that system, but that's a special case. For everything else, if your script has an extra dependency on a specific shell, it would most likely make more sense to use a more powerful language with possibly a *different* runtime dependency.
That said, sure, you will use an "obscure" language. The trick is: Think about the right tool for the job upfront. The #shell can be very powerful for a certain class of problems, e.g. as an orchestration layer for separate tools offering "shell-friendly" interfaces like flexible commandline arguments and a stdin/stdout format that's easy to parse for a shell script.
Here's my latest non-trivial work in shellscript and I'd use shellscript again for the same job:
https://github.com/Zirias/dos2ansi/blob/master/src/bin/showansi/showansi.in.tmpl
In a nutshell, it orchestrates xterm, less and my own dos2ansi tool to build an ansi-art viewer. It might be a bit "borderline" because it contains obscure functions to parse some string character by character (something a shell can't do in a sane way), but I think that was a fair price for avoiding to depend on some other interpreter, it's still a relatively short script.
Gotta say, I wish #bash had local / lexically-scoped functions, rather than having to rely on hacks like:
function widget {
function ___widget_parse {
...
}
...
unset ___widget_parse
}
Something like this (which does not currently work) would be lovely:
function widget {
local function parse {
...
}
}
Bashing Out A Simple Battery Status Script In Bash
https://eggflix.foolbazar.eu/videos/watch/4bd22c77-42ea-4d69-92cf-c486d63158fb
SQUEAKEY: The Essential Linux Cleanup Script for Secure File Deletion
In the world of Linux administration, maintaining a clean system is crucial for performance and security. Enter SQUEAKEY, a powerful script designed to streamline your cleanup process while ensuring y...
https://news.lavx.hu/article/squeakey-the-essential-linux-cleanup-script-for-secure-file-deletion
How to Use the declare Command in Bash Scripts #declare #Bashscripting #Shellscript #Bash #Linux #Linuxcommands #Linuxhowto #Variables #Functions
https://ostechnix.com/bash-declare-command-usage/
@NOISEBOB #HowTo run #ShellScript when sound in mic
Here is a #bash function "getvol" which uses #SoX to listen for 0.1 second and then tells you peak volume, between 0 and 1:
function getvol {
rec -p trim 0 .1 stat 2>&1 >/dev/null | grep -Po "(?<=Maximum amplitude:).*" | grep -Po "\S+"
}
You can loop the function and do something if the volume is high enough.
#genuary7 in the bash mountains... #bash #shellscript #genuary #genuary2025 - software not intended to create art.
Oil updates are always as interesting read for shell nerds https://www.oilshell.org/blog/2024/12/objects.html
Qiita - 人気の記事 
sed: https://pubs.opengroup.org/onlinepubs/9699919799/utilities/sed.html$( ... ) for command replacement instead of only backticks. #FreeBSD's /bin/sh is (AFAIK) POSIX compliant, but I'd assume even this shell can do a few things not specified in POSIX. For testing, I found shells/bosh very useful, it contains a few flavors of minimal shells, one of them a POSIX shell.sh doesn't know them with the single exception of the "argv" array (both for the main script and any shell function), which you can also modify using set, but that of course has other implications. What's always available is word splitting, any variable can contain a list separated by whatever $IFS is set to. It defaults to whitespace. You may override $IFS, but that can be tricky as well, word splitting is used a lot, so expect surprising effects. 
Another week another backlog project release! Another Git extension, and with git-activity (my cross-repo Git log / standup-prep tool) and git-random (my Git tree building tool) one I use a lot:
git-commit-message-summary-length measures the length of a commit message's first line, and compares that to soft and hard limits.
Pythonのshというライブラリを使うと、`sh.ls("-la")`みたいな感じにPythonプログラムからコマンドが実行できる。これ、いいですね #python #shellscript
sh — sh 2.0.6 documentation: https://sh.readthedocs.io/en/latest/
