I had a cleanup script that always started with the usual set -euo pipefail. One day it reported success while half the work hadn’t happened. Here’s a stripped-down version of what bit me:

#!/usr/bin/env bash
set -euo pipefail

cleanup_old() {
  rm "$1/old.log"        # fails if the file is missing
  echo "cleaned $1"
}

if cleanup_old /tmp/nope; then
  echo "all good"
fi

Output:

rm: cannot remove '/tmp/nope/old.log': No such file or directory
cleaned /tmp/nope
all good

The rm fails, but the function keeps going, and the echo at the end gives it a zero exit status. The bash manual says -e is ignored for any command in a context where the exit status is being tested (if, while, &&/|| lists, !). That also applies to everything inside a function called from such a context. set -e at the top of the file doesn’t help, and nothing warns you.

What I do now:

cleanup_old() {
  rm "$1/old.log" || return 1
  echo "cleaned $1"
}

The explicit || return is noisier, but it works regardless of how the function gets called. For anything where partial success is dangerous, I also stopped using functions as if conditions and run them as plain statements, checking $? or using || on the call site deliberately.

Related one that bit me the same week: local out=$(some_cmd) always returns the exit status of local, not some_cmd. Splitting it into local out; out=$(some_cmd) fixes it.

I’ve been reading a lot of generated and copy-pasted scripts lately, and nearly all of them treat set -euo pipefail as a safety net. After this, I think of it as a default that works in the simple cases and quietly stops working in exactly the places where functions get composed.

For those who write larger bash scripts: do you rely on set -e at all, or do you handle errors explicitly everywhere and keep -e only as a backstop?

I maintain jc, which converts command output and common file types to JSON so you can query them with jq instead of grep/awk/cut. A couple of newer parsers turned out to be handy in Bash scripts, so I wrote up some examples.

Why not just awk?

authorized_keys looks like a whitespace-delimited file, but it isn't. Lines can start with an optional, comma-separated options field, and option values can be quoted strings with spaces in them. So the field positions shift from line to line. Here's a sample file:

ssh-ed25519 AAAAC3Nza... kelly@laptop
command="/usr/bin/rsync --server --sender -logDtpre.iLsfxC . /srv/backup",no-port-forwarding,no-pty ssh-rsa AAAAB3Nza... backup@nas
from="10.0.8.0/24",no-agent-forwarding ecdsa-sha2-nistp256 AAAAE2Vj... ci-runner@build01
ssh-ed25519 AAAAC3Nza...

The obvious awk one-liner to print the key type and comment:

$ awk '{print $1, $3}' ~/.ssh/authorized_keys
ssh-ed25519 kelly@laptop
command="/usr/bin/rsync --sender
from="10.0.8.0/24",no-agent-forwarding AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlz...
ssh-ed25519

Only the first line is right. Looking for RSA keys with awk '$1=="ssh-rsa"' returns nothing, because the one RSA key has options in front of it.

grep has the opposite problem: it matches text anywhere on the line. grep -v 'command=' to find unrestricted keys also drops a key whose comment says "no command= needed". And grep ssh-rsa matches a restricted ed25519 key whose forced command happens to contain the string ssh-rsa.

With jc --authorized-keys, every line comes out with the same fields, so there's no guessing:

$ jc --authorized-keys < ~/.ssh/authorized_keys | jq -r '.[] | "\(.type) \(.comment // "(no comment)")"'
ssh-ed25519 kelly@laptop
ssh-rsa backup@nas
ecdsa-sha2-nistp256 ci-runner@build01
ssh-ed25519 (no comment)

options is always an array, quoted values like command="echo ssh-rsa disabled; exit" stay intact, and multi-word comments are kept whole.

Tag every key with its owner, then query the whole box

A loop adds a user field to each key and emits JSON Lines:

for f in /home/*/.ssh/authorized_keys; do
    u=$(echo "$f" | cut -d/ -f3)
    jc --authorized-keys < "$f" | jq -c --arg u "$u" '.[] | . + {user: $u}'
done > keys.jsonl

Now each question is just a different jq filter. Which keys have no from= or command= restriction?

jq -r 'select(any(.options[]; startswith("from=") or startswith("command=")) | not)
       | "\(.user)  \(.type)  \(.comment // "(no comment)")"' keys.jsonl

Because this checks the options array instead of the whole line, comments and key data can't cause false matches.

Is the same key authorized for more than one user?

jq -s -r 'group_by(.key)[] | select(length > 1)
          | "\(.[0].comment // "(no comment)"): \(map(.user) | join(", "))"' keys.jsonl

Which legacy RSA or DSA keys are still around?

jq -r 'select(.type == "ssh-rsa" or .type == "ssh-dss") | "\(.user)  \(.comment)"' keys.jsonl

(Run the loop with sudo if you need to read other users' files.)

Bonus: a change-freeze guard from a shared calendar

.ics files are worse for line tools: long lines get folded onto the next line, and parameters are jammed into property names (DTSTART;TZID=America/Los_Angeles:20261019T090000). The --ics parser unfolds all of that and normalizes timestamps to ISO 8601. That means jq's fromdateiso8601 and now can check whether you're inside a freeze window, and jq -e turns the result into an exit code:

if jc --ics < freeze.ics | jq -e '
    [.[] | select(.categories[]? == "Freeze")
         | select((.dtstart | fromdateiso8601) <= now and now < (.dtend | fromdateiso8601))]
    | length > 0' > /dev/null
then
    echo "Change freeze in effect. Aborting deploy." >&2
    exit 1
fi

(This works with UTC timestamps, the ones ending in Z. Events with a TZID come through as local time with a separate dtstart_tzid field.)

Full write-up, which also covers headerless CSV/TSV files: JC Tips and Tricks – Part 3

What file formats are you still parsing by hand in your scripts?

I took your feedback on bash2json, (wasted another year in local testing), and made: shelljq, new JSON parser for shell
it's built on bash2json's json_to_arr function as core for most operations, as well as:
- new name
- ZSH support (+ macOS)
- deeper integration inside scripts (including autogenerated functions documentation)
- own storing format for nested objects
- more powerful typechecking and JSON validation
- completely reworked `json_trim` for the best performance
- testing suite

shelljq is something I personally use in my projects (e.g. upcoming bashcord v2) and had high hopes for reliable tool which can be integrated into any script

shjq is cross-shell for both bash and zsh

I'm open to any critique, this project is still alpha and may still contain many bugs

let me know if i should provide usage examples, i wasn't sure on where to put them

New to Linux. Installed Ubuntu. Keep reloading youtube home page because recommendations suck. Want to to avoid shorts and other unneeded features by using Youtube solely through bash. Want to know if small quality of life changes can be made.

I'm wondering if it's possible to use the terminal to show a small number of videos from my home page, title with no thumbnail is enough, which shows dislike and like count, make it so that pressing not interested or don't recommend channel is a bit faster to click.

Sorry if this is a weird or absurd ask. I'm going cold turkey on AI overview, but want to see if there should be anything I need to know about starting a project like this.

So this is super weird. When I run the following in a script (or manually in the terminal), it does exactly what you'd expect.

```Bash declare -A myassoc myassoc[key]="Hello World"

unset myassoc declare -p myassoc echo "This should be empty: ${myassoc[@]}" OUTPUT: ./unsetLovalVar: line 9: declare: myassoc: not found This should be empty: ``

As expected, myassoc is unset and therefore undeclared

however if I wrap that code in a function, the myassoc becomes unset but not undeclared. ```Bash foo () { declare -A myassoc myassoc[key]="Hello World"

unset myassoc declare -p myassoc echo "This should be empty: ${myassoc[@]}" } foo OUTPUT: declare -- myassoc This should be empty: ```

This is very annoying since I use declare -p to test if variables exist regardless of their type and content.

I have tested this on two machines in Debian and Ubuntu on Bash 5.2.something with the same issue.

test is not a viable alternative, since it doesn't have the same behaviour for local myvar and declare myvar (vars without value return false, even if declared)

Does anyone have a workaround?

EDIT:

So I found this StackExchange topic which seems to conclude that this is simply not possible within the same scope.

Here is where it gets REALLY insane:

```Bash bar () { declare -A myassoc myassoc[key]="Hello World"

    declare -p myassoc
    echo "This should not be empty: ${myassoc[@]}"

    foo () {
            unset myassoc
            echo "In foo:"
            declare -p myassoc
            echo "This should be empty: ${myassoc[@]}"
    }
    foo

    echo "After foo:"
    declare -p myassoc
    echo "This should be empty: ${myassoc[@]}"

} bar ``` <sup>\</sup>please excuse the ridiculous indents, I havent gotten around to taming nvim yet))

THIS WORKS FOR ABSOLUTELY NO REASON: Bash OUTPUT: declare -A myassoc=([key]="Hello World" ) This should not be empty: Hello World In foo: ./unsetLocalVar: line 12: declare: myassoc: not found This should be empty: After foo: ./unsetLocalVar: line 17: declare: myassoc: not found This should be empty:

The solution is to wrap the unset in a nested function.

i made a script that actually works for most times to update brave browser, but for packages that change names its trivial. the idea is to place, update directory with a file with metadata that i can extract. here is the script :

updatePrograms() {
for dir in ~/Programs/*; do
#meta file structure
if [[ -f "$dir"/update/meta ]]; then
local metadata=$(cat "$dir"/update/meta)
local owner=$(  echo "$metadata" | grep "Owner"   | sed 's|Owner:||'  )
local project=$(echo "$metadata" | grep "Project" | sed 's|Project:||')
local output=$(curl -fsS "https://api.github.com/repos/$owner/$project/releases/latest")
[[ -z "$output" ]] && { echo "no response for $project"; continue; }
local checkVersion=$(jq -r '.tag_name' <<< "$output")
echo "updatable Project : $project"

[[ "$checkVersion" = "null" ]] || [[ -z "$checkVersion" ]] && { echo "couldn't fetch version for $project"; continue; }

local currentVersion=$(echo "$metadata" | grep "Version" | sed 's|Version:||')
[[ "$checkVersion" = "$currentVersion" ]] && { echo "$project is up to date : $checkVersion"; continue; }

while true; do
read -p "$project is on $currentVersion, latest is $checkVersion; do you want to request the latest Version? [y/n]: " response
case "$response" in
[Yy])
echo "Updating.."
local name
 name=$(echo "$metadata" | grep "AssetName" | sed 's|AssetName:||')

   local url=$(jq -r --arg name "$name" '.assets[] | select(.name == $name) | .browser_download_url' <<< "$output")

 if [[ -z "$url" ]] || [[ "$url" = "null" ]]; then
   echo "couldn't find asset matching $name"
   echo "you may need to change asset name version to $checkVersion"
        break
 fi

if  curl -fL -o "$dir/update/$name" "$url"  ; then
sed -i "s|Version:.*|Version:$checkVersion|" "$dir"/update/meta
else
echo "Downloading falied"
break
fi

break;;
[Nn])
echo "not Updating"
break;;
   *)
echo "choose y or n";;
esac
done
fi
done
}

For all those who want simple backups of their machines, I have created a tiny bash wrapper around Kopia: https://github.com/bderenzo/tinybackup

From a single minimal config file, it handles repository setup, retention, ignore rules and pre/post backup hooks, etc.

It can back up to a local disk, SFTP, S3 or any rclone remote, and lets you browse snapshots through CLI, a mount point or the Kopia web UI.

```bash

!/usr/bin/env bash

function main() {

# Phase 1: Setup and Run Dev Server
printf "%s\n" "Starting development server..."
cd "$HOME/Desktop/my-project-1" || exit 1

# Run the dev server in the background
rm -rf coverage dist && npm run lint && npm run coverage && npm run test && npx tsc || exit 1
npx tsx watch --env-file=.env.development  src/index.ts > "/tmp/server.log" 2>&1 &
DEV_PID=$! # Store the Process ID of the 'dev' server

# Monitor for "server is listening"
printf "%s\n" "Waiting for server startup message..."

while ! grep -q "Server is now listening" "/tmp/server.log"; do
    printf "%s\n" "Server not yet ready. Still waiting..."
    sleep 1 # Wait 5 seconds before checking the log again
done

printf "%s\n" "SUCCESS: Server is listening. Proceeding to Phase 2."

# Phase 2: API Call and Wait
printf "%s\n" "Executing API call..."
rm -rf /tmp/test_app && curl -X POST http://localhost:3003/job/node/express/basic/generator

# Monitor for "downloading..." message in logs...
printf "%s\n" "Waiting for download completion..."

# Wait for the download confirmation
while ! grep -q "downloading docker container files completed successfully" "/tmp/server.log"; do
    printf "%s\n" "Waiting for download confirmation..."
    sleep 1
done

# Phase 3: Cleanup
printf "%s\n" "Shutting down services..."
kill ${DEV_PID} # Use the stored PID to gracefully stop the server process

printf "%s\n" "Moving into generated code..."
cd "/tmp/test_app" && npm install && code "/tmp/test_app" && cd "$HOME" || exit 1

}

main "$@"

```

I wrote a ~1500-line bash file manager. fzf for the picker, eza for listing, Kitty's graphics protocol for inline image/video/PDF previews. Everything else is stock coreutils.


Repo: https://github.com/eHab-codeX/fm

Why post it here

r/commandline got the "here's a tool" version last week. The bash bits are probably more interesting to this crowd, so here they are.

The bash-specific parts

Double-click detection without EPOCHREALTIME getting in the way. EPOCHREALTIME returns a locale-formatted decimal — . in en_US, , in de_DE. Strip the separator before comparing:

now=${EPOCHREALTIME/[.,]/}
(( idx == last_idx && now - last_t < 400000 ))   # 400ms

A hand-rolled CSI/SS3 parser for the gallery grid. The full-screen grid needs arrow keys, PgUp/PgDn, Home/End, and SGR mouse events. Rather than depend on a helper, it reads bytes into a buffer and dispatches on the final byte:

case "$final" in
  A) KEY=up ;; B) KEY=down ;;
  C) KEY=right ;; D) KEY=left ;;
  '~') case "${seq%%;*}" in
         5) KEY=pgup ;; 6) KEY=pgdn ;;
       esac ;;
esac

The tricky part is not swallowing stray bytes: an unknown CSI sequence (\e[1;5H for Ctrl+Home, for example) has to be fully consumed or it leaks into the next read as literal characters.

**stty -g around the alternate screen.** The grid switches to cbreak mode (stty -icanon -echo min 1 time 0). Saving the previous state and restoring it in the EXIT trap is what keeps Ctrl-C from leaving the terminal in a broken state:

STTY_SAVED=$(stty -g </dev/tty) || STTY_SAVED=""
trap '[[ -n "$STTY_SAVED" ]] && stty "$STTY_SAVED" </dev/tty' EXIT

Two-phase rename so swaps work. A naive mv old new loop breaks a→b, b→a. First move every source to a temp name, then move temps to final names:

for k in "${!ro[@]}"; do
    mv -T -- "${ro[k]}" "${ro[k]}.fm-tmp.$$"
done
for k in "${!ro[@]}"; do
    mv -T -- "${ro[k]}.fm-tmp.$$" "${rn[k]}"
done

Parallel thumbnails by self-invocation. The thumbnail builder is the same script with --thumb-any:

printf '%s\0' "${slice[@]}" | \
    xargs -0 -r -n1 -P"$(nproc)" bash "$SELF" --thumb-any

Bash dispatches; ImageMagick/ffmpeg/pdftoppm do the work.

GNU vs BSD head. head -z is GNU-only. A contributor on macOS sent a PR that falls back to ghead, then to a pure-bash reader:

while ((count < $1)) && IFS= read -r -d '' record; do
    printf '%s\0' "$record"
    ((++count))
done

What I'd want reviewed

• The escape parser in _g_readkey — there are terminals that emit sequences it might mis-handle (Konsole? older tmux?).
• The _fm_list sort pipeline — it does one batched stat and one awk pass, then sort -V. I'm not 100% sure the tie-breaking behavior for identical timestamps is stable.
• Anything in _trash_and_record — I'm handling the Freedesktop .trashinfo format's Path= percent-encoding with a bash-only encoder, which is probably slower than it should be.

Requirements

Bash 5+ (uses EPOCHREALTIME and ${var,,}). Linux is the primary target; macOS works with GNU coreutils installed (the _head0 helper falls back to bash-only if ghead isn't present).

git clone https://github.com/eHab-codeX/fm.git ~/.local/share/fm
ln -sf ~/.local/share/fm/fm ~/.local/bin/fm

MIT.

I made this bash script for quickly doing chmod +x on sh files, uses zenity. Tell me if its any good or not

#!/bin/bash

zenity --info --title=".sh-executabler" --text="Welcome to the .sh-executabler" --ok-label="Next"

status=$?

if [ $status -ne 0 ]; then

zenity --info --title=".sh-executabler" --text="Wizard cancelled."

exit 0

fi

# Select which .sh file to chmod +x

target_dir=$(zenity --file-selection --title=".sh-executabler" --file-filter="Shell scripts | *.sh")

status=$?

if [ $status -ne 0 ]; then

zenity --info --title=".sh-executabler" --text="No file chosen."

exit 0

fi

# Check if file doesnt exist. Its kinda redundant since im already using file selection which you cant select files that dont exist but i keep it here anyways

if [ -f "$target_dir" ]; then

true

else

zenity --error --title=".sh-executabler" --text="The file doesnt exist."

exit 0

fi

chmod +x "$target_dir"

zenity --info --title=".sh-executabler" --text="The file has successfully been made executable." --ok-label="Finish"

exit 0

You don’t want to know what hoops I’ve jumped through to implement FPATH in bash. Then today I innocently asked GPT how it would implement FPATH in bash and it introduced me to this hook.

Now have to go home now get rid of a lot of needless code. Oh well. Less code is the best code!

When I run ls ~/Music/ | shuf | tail -1 | read file && echo $file it gives a random output as expected, but every time I run this script it plays a file labeled "3S.mp3" exclusively, which just so happens to be the first one in the list when I run ls

Does anyone know what could be causing this?

When I was new to Bash/Shell I really didn't understand how to select or remove different parts of strings, and only used examples from forums without understanding at all how they worked. But then I read the man page for Bash (go figure...) and finally understood. I'd like to share in hope that it will be helpful to anyone starting out with Bash scripting. The examples work in POSIX shell also.

Example: select everything after the last _ in the string str='first_second_third_fourth'

```

Selecting everything after the last '_' is the same as removing everything

before the last '' and the '' itself.

So check 'Remove matching prefix pattern' in 'man bash'.

${str##_} will remove the longest match of the pattern '_' starting

from the beginning of string and leave us with just 'fourth'.

str='firstsecond_third_fourth' echo "${str##*}" ```

Example: pick out second from the string str='first_second_third_fourth'

```

We need to remove everything before the first '_' so we'll use

'second=${str#*_}' to remove the shortest match from the beginning.

Variable 'second' now contains 'second_third_fourth' so we need to

get rid of everything after the first '_'.

See 'Remove matching suffix pattern' in the manual.

We want to remove the longest match of pattern '_*' starting

from the end of the string. So '${second%%_*}' is what we need.

All in all:

str='firstsecond_third_fourth' second="${str#*}" second="${second%%_*}" echo "$second" ```

Example: find the file extension (with the dot) of /home/user/Pictures/test.webp ```

The extension is the thing after the last '.'. So use '${f##*.}'

This will delete the '.' also, so let's add that back in

f='/home/user/Pictures/test.webp' ext=".${f##*.}" echo "$ext" ```

Example: convert a png to jpg ``` pngfile='original.png'

We need to replace the .png with a .jpg. I.e. delete .png and add .jpg

jpgfile="${pngfile%.png}.jpg" echo convert "$pngfile" "$jpgfile"

Notice that if pngfile doesn't end in .png, jpgfile will at least not

be the same file, so pngfile will not be overwritten.

```

Example: Remember to escape characters that are special in pattern matching ```

Remove the first sentence in this string

str='Hello? Anybody there?'

This will not work since '?' is a pattern matching exactly one character,

This will only remove the beginning 'H' ('*' matches nothing in this case)

echo "${str#*?}"

The solution is to make the '?' literal by escaping it or quoting it

echo "${str#\?}" echo "${str#'?'}"

The same goes for '*', '[' and ']'. And probably a few more as well,

especially if extglob is turned on

```

We create applications and output debugging and status information to stdout. Then when these are run in the background that all ends up in the bit bucket.

But when you need to debug something and you don't want to disturb the process what do you do? I could kill it and then run it in the foreground. But that disturbs things too much.

Okay, so what if `stdout` gets logged to a `stdout.log file`? Since I own the OS that was a light-weight change. It works. And I can use `CAT -M stdout.log` which is my equivalent to `tail -f stdout.log`.

Okay, but then I have a unit that is running 5 applications. One of which the author is always very verbose in the foreground (sounds like a personal/personnel problem). That overwhelms the log. Those age to BAK and monitoring the log sucks.

So here is my solution. Your thoughts?

\--------------

Here is what I have implemented for this. By default background processes will **not** log `stdout` output unless if already has the log file. So there would be no net change from JANOS v2.5.3.

If you want to log background process output generally, you can use the following command:

touch stdout.log

All `stdout` from all background processes will then be captured in this file. The `stdout.log` file must first exist before it will collect `stdout` stream data.

This will age to `stdout.log.bak` as any other log file would.

You can stop logging by removing (or renaming) this file.

When there are multiple applications running. You may optionally create an application specific `stdout` log file also using the `TOUCH` command. This file must be named using the specific application name. For example:

touch stdout-tasker.log

The application name is everything after the last '/' in the process name reported by `PS`. If that includes `.jar` then the stdout file name should also. I tend to not include the `.jar` in `Run` keys as that will be carried to the process name. It is unnecessary.

This will route output from the application to that specific file which will age accordingly. Meanwhile, if it exists, other applications would still log to `stdout.log`.

So this lets you enable `stdout` capture for a specific process and then monitor it.

spent a while chasing a bug that wasn't there, so here's the tell.

i had a polling script running in the background and edited it while it was going. started getting s: command not found and pr: unbound variable. nothing in the file looked like that. i went and "fixed" a couple of things that were never broken.

bash doesn't read the whole file up front, it reads as it goes by byte offset. edit the file and it resumes at whatever byte it was at, which is now the middle of some other line. s and pr were fragments of words that used to be somewhere else.

quick way to rule it in or out: if the error says line 214 and the file only has 190 lines, it's this, not a real bug.

fixes: cp the script and run the copy, or put everything in a main() and end the file with main "$@"; exit on one line, so bash never reads past it.

edit: thanks to the comments, bash reads the file in blocks (up to 8192 bytes), not literally byte by byte, and calling main alone isn't enough, the exit has to be on the same line.

hi! it’s my first time using bash can someone help me with this and explain what’s missing

#!/bin/bash

for i in “/data/folder”/*; do

/folder/munge_sumstats.py \

- -sumstats “$i” \

- -chunksize 500000 \

- -snp rsID \
etc..

- -out another/folder/ (i dont know what to puT here)

done

Thank you so much !

Hello! I'm new to Linux and Bash. This script is supposed to be a part of a GitHub workflow for publishing my Bevy game to GitHub pages.

It's supposed to do this: (Each list entry corresponds to a STAGE in the script.)

1. Identifies what distribution is being used, currently supports only Arch, CachyOS and Ubuntu (GitHub actions use Ubuntu). Updates the system and installs dependencies needed for compilation.
2. Updates the Rust installation using rustup update install the nightly tool-chain, set it as default and install the wasm32-unknown-unknown target.
3. Checks if wasm-bindgen-cli isn't already installed, if it isn't it installs it.
4. Compiles the project in release mode with the above mentioned target.
5. Generates the dist/ folder by first creating dist/ and dist/assets then copies contents of the web/ folder, which now contains only index.html, to dist/ also copies contents of assets/ to dist/assets/ and finally uses wasm-bindgen to generate bindings for the project.

Here's the script:

#!/bin/bash



# Variables.


. /etc/os-release # Bring needed variables to scope.


PROJECT_NAME="comfort-3d"; # Name.
HUMAN_PROJECT_NAME="Comfort 3D"; # Human readable name.


WASM_BINDGEN_BIN="wasm-bindgen"; # Name of wasm-bindgen-cli executable.


DIST_FOLDER=dist/; # Distribution folder.
DIST_ASSETS_FOLDER=dist/assets/; # Distrubution assets folder.
WEB_FOLDER=web/.; # Web folder.
ASSETS_FOLDER=assets/.; # Assets folder.


RUST_TOOLCHAIN="nightly-x86_64-unknown-linux-gnu"; # Nightly Rust toolchain.
RUST_TARGET="wasm32-unknown-unknown"; # Rust wasm target.


# Dependencies for Arch and Arch derived distros.
DEPENDENCIES_ARCH="libx11 pkgconf alsa-lib libxcursor libxrandr libxi gcc git pipewire-alsa pulseaudio-alsa vulkan-intel vulkan-radeon mold";


# Dependencies for Ubuntu.
DEPENDENCIES_UBUNTU="g++ mold clang git pkg-config libx11-dev libasound2-dev libudev-dev libxkbcommon-x11-0 vulkan-radeon vulkan-intel mesa-vulkan-drivers";


# File needed for wasm-bindgen.
WASM_FILE=target/wasm32-unknown-unknown/release/${PROJECT_NAME}.wasm;


# Color and format variables.
BOLD="\e[1m";
RESET_FORMAT="\e[0m";
RED="\e[91m";
GREEN="\e[92m";
CYAN="\e[96m";



# STAGE 1: Update system, Install needed dependencies, Install toolchain and target.


case $ID in # Variable comes from ". /etc/os-release"!
  ubuntu)
      echo -e "${CYAN}This is Ubuntu! Updating system...${RESET_FORMAT}";

      # Update system.


      if sudo apt-update && sudo apt-upgrade 2>&1; then
        echo -e "${GREEN}Successfully updated system!${RESET_FORMAT}";
      else
        echo -e "${BOLD}${RED}There was an error updating the system! Aborting...${RESET_FORMAT}";
        exit 1;
      fi


      # Install dependencies, make sure gcc and mold is installed.


      echo -e "${CYAN}Installing dependencies...${RESET_FORMAT}";


      if sudo apt-get install $DEPENDENCIES_UBUNTU 2>&1; then
        echo -e "${GREEN}Successfully installed dependencies!${RESET_FORMAT}";
      else
        echo -e "${BOLD}${RED}There was an error installing dependencies! Aborting...${RESET_FORMAT}";
        exit 1;
      fi
    ;;


  arch) 
      echo -e "${CYAN}This is Arch! Updating system...${RESET_FORMAT}";


      # Update system.


      if sudo pacman -Syu 2>&1; then
        echo -e "${GREEN}Successfully updated system!${RESET_FORMAT}";
      else
        echo -e "${BOLD}${RED}There was an error updating the system! Aborting...${RESET_FORMAT}";
        exit 1;
      fi


      # Install dependencies, make sure gcc and mold is installed.


      echo -e "${CYAN}Installing dependencies...${RESET_FORMAT}";


      if sudo pacman -S $DEPENDENCIES_ARCH 2>&1; then
        echo -e "${GREEN}Successfully installed dependencies!${RESET_FORMAT}";
      else
        echo -e "${BOLD}${RED}There was an error installing dependencies! Aborting...${RESET_FORMAT}";
        exit 1;
      fi
    ;;


  cachyos)
      echo -e "${CYAN}This is CachyOS! Updating system...${RESET_FORMAT}";


      # Update system.


      if sudo pacman -Syu 2>&1; then
        echo -e "${GREEN}Successfully updated system!${RESET_FORMAT}";
      else
        echo -e "${BOLD}${RED}There was an error updating the system! Aborting...${RESET_FORMAT}";
        exit 1;
      fi


      # Install dependencies, make sure gcc and mold is installed.


      echo -e "${CYAN}Installing dependencies...${RESET_FORMAT}";


      if sudo pacman -S $DEPENDENCIES_ARCH 2>&1; then
        echo -e "${GREEN}Successfully installed dependencies!${RESET_FORMAT}";
      else
        echo -e "${BOLD}${RED}There was an error installing dependencies! Aborting...${RESET_FORMAT}";
        exit 1;
      fi
    ;;


  *)
      echo -e "${BOLD}${RED}This is an unknown distribution! Aborting...${RESET_FORMAT}";
      exit 1;
      ;;
esac



# STAGE 2: Update Rust, Install toolchain, Set toolchain as default, Install target wasm32-unknown-unknown.


echo -e "${CYAN}Updating Rust with rustup...${RESET_FORMAT}";


if rustup update 2>&1; then
  echo -e "${GREEN}Successfully updated Rust using rustup!${RESET_FORMAT}";


  echo -e "${CYAN}Installing Rust toolchain...${RESET_FORMAT}";


  if rustup toolchain install "$RUST_TOOLCHAIN" 2>&1; then
    echo -e "${GREEN}Sucessfully installed ${RUST_TOOLCHAIN}!${RESET_FORMAT}";


    echo -e "${CYAN}Setting $RUST_TOOLCHAIN as default...${RESET_FORMAT}";


    if rustup default "$RUST_TOOLCHAIN" 2>&1; then
      echo -e "${GREEN}Sucessfully set $RUST_TOOLCHAIN as default!${RESET_FORMAT}";


      echo -e "${CYAN}Installing target ${RUST_TARGET}${RESET_FORMAT}";


      if rustup target add $RUST_TARGET >/dev/null 2>&1; then
        echo -e "${GREEN}Sucessfully installed target ${RUST_TARGET}${RESET_FORMAT}";
      else
        echo -e "${RED}${BOLD}There was an error installing target ${RUST_TARGET}! Aborting...${RESET_FORMAT}";
        exit 1;
      fi
    else
      echo -e "${BOLD}${RED}There was an error setting $RUST_TOOLCHAIN as default! Aborting...${RESET_FORMAT}";
      exit 1;
    fi
  else
    echo -e "${BOLD}${RED}There was an error installing ${RUST_TOOLCHAIN}! Aborting...${RESET_FORMAT}";
    exit 1;
  fi
else
  echo -e "${BOLD}${RED}There was an error updating Rust using rustup! Aborting...${RESET_FORMAT}";
  exit 1;
fi



# STAGE 3: Check for wasm-bindgen-cli, if missing install it.


if command -v "$WASM_BINDGEN_BIN" >/dev/null 2>&1; then
    echo -e "${GREEN}Binary $WASM_BINDGEN_BIN is intalled!${RESET_FORMAT}";
else
    echo -e "${BOLD}${RED}Binary $WASM_BINDGEN_BIN could not be found! Installing...${RESET_FORMAT}"

    if ! cargo install wasm-bindgen-cli >/dev/null 2>&1; then
      echo -e "${BOLD}${RED}There was an error installing wasm-bindgen-cli! Aborting...${RESET_FORMAT}";
      exit 1;
    fi
fi



# STAGE 4: Compile project with target wasm32-unknown-unknown.


echo -e "${CYAN}Compiling project with target ${RUST_TARGET}${RESET_FORMAT}";


if cargo build --release --target $RUST_TARGET >/dev/null 2>&1; then
  echo -e "${GREEN}Sucessfully compiled project with target ${RUST_TARGET}${RESET_FORMAT}";
else
  echo -e "${RED}${BOLD}There was an error compiling project with target ${RUST_TARGET}! Aborting...${RESET_FORMAT}";
  exit 1;
fi



# STAGE 5: Assemble dist folder.


echo -e "${CYAN}Generating $DIST_FOLDER folder...${RESET_FORMAT}";


if mkdir -p $DIST_FOLDER >/dev/null 2>&1; then # Create dist/.
  if mkdir -p $DIST_ASSETS_FOLDER >/dev/null 2>&1; then # Create dist/assets/.
    if cp -a $WEB_FOLDER $DIST_FOLDER >/dev/null 2>&1; then # Copy web/ contents to dist/.
      if cp -a $ASSETS_FOLDER $DIST_ASSETS_FOLDER >/dev/null 2>&1; then # Copy assets/ contents to dist/assets.
        if wasm-bindgen --out-name $PROJECT_NAME --out-dir $DIST_FOLDER --target web $WASM_FILE 2>&1; then # Use wasm-bindgen to generate files.
          echo -e "${GREEN}Sucessfully generated ${DIST_FOLDER} folder!${RESET_FORMAT}";
        else
          echo -e "${RED}${BOLD}There was an error generating ${DIST_FOLDER}! Aborting...${RESET_FORMAT}";
          exit 1;
        fi
      else
        echo -e "${RED}${BOLD}There was an error copying files from $ASSETS_FOLDER to ${DIST_ASSETS_FOLDER}! Aborting...${RESET_FORMAT}";
        exit 1;
      fi
    else
      echo -e "${RED}${BOLD}There was an error copying files from $WEB_FOLDER to ${DIST_FOLDER}! Aborting...${RESET_FORMAT}";
      exit 1;
    fi
  else
    echo -e "${RED}${BOLD}There was an error creating ${$DIST_ASSETS_FOLDER}! Aborting...${RESET_FORMAT}";
    exit 1;
  fi


else
  echo -e "${RED}${BOLD}There was an error creating ${DIST_FOLDER}! Aborting...${RESET_FORMAT}";
  exit 1;
fi

The script works as expected but I don't know if there aren't some weird edge cases and such.

I've written this backup script for use copying my files from point A to point B. The goal is a full snapshot of files. For this first iteration, I'm ok with hard coding file paths.

I've removed everything except logic for rsync, diff, and logging. Are there any logic issues?

# backup script that performs full backups and verifies the result.

#!/bin/bash

set -euo pipefail

DATE_STAMP=$(date +%Y-%m-%d_%H-%M-%S)
BACKUP_LOCATION="$HOME/backup-location-path/$DATE_STAMP" 
LOG_LOCATION="$HOME/log-location-path/"
LOGFILE_NAME="backup_${DATE_STAMP}.log"

SOURCE_DIRS=(
    "$HOME/source1"
    "$HOME/DOES-NOT-EXIST"  # DNE for error handling
    "$HOME/source2"
)

# check if source matches destination
diff_source_and_destination() {
    local base
    base=$(basename "$SRC")
    diff -r "$SRC" "$BACKUP_LOCATION"/"$base" 
}

# Check for the existence of $SRC and print an alert if it wasn't found.
check_source_exists() {
    if [ -e "$SRC" ]; then
        echo "[SOURCE = $SRC] found. Copying..."
        return 0
    else
        echo "[SOURCE = $SRC] WAS NOT FOUND!" | tee -a "$LOG_LOCATION/$LOGFILE_NAME" 
        return 1
    fi
}

copy_data_and_log() {
    {
        rsync -a --stats "$SRC/" "${DESTINATION}/" 
    } | tee -a "$LOG_LOCATION"/"$LOGFILE_NAME"
}

mkdir -p "$BACKUP_LOCATION"
mkdir -p "$LOG_LOCATION"

echo "Copying files to [BACKUP LOCATION =${BACKUP_LOCATION}]"

for SRC in "${SOURCE_DIRS[@]}"; do
    # Print and log a warning if SRC wasn't found
    check_source_exists || continue
    DESTINATION="$BACKUP_LOCATION/$(basename "$SRC")"
    copy_data_and_log
    echo "rsync completed for $SRC."
    diff_source_and_destination 
done

echo "Finished copying operations to [BACKUP LOCATION = ${BACKUP_LOCATION}]"

Hello everyone!

I built a pure Bash 4+ runtime for Lexis, a minimalist i18n engine designed under the Unix philosophy for CLI tools and shell scripts.

It handles translation lookup entirely in native shell logic using an eager+lazy model: it loads and validates .lex key::value files into associative arrays, and lazily parses escape sequences and printf interpolations on first access with zero subshells or external binaries (sed/awk).

Real-World CLI Example (AuraConfig i18n module)

Here is a practical demonstration of localizing a CLI tool like auraconfig:

1. Translation File (lang/en.lex):

cli.config_loaded::Configuration loaded successfully from %s.
cli.option_set::Option '%s' set to '%s'.
cli.error_not_found::Error: Configuration key '%s' does not exist.

2. Shell Script (i18n.sh):

#!/usr/bin/env bash
source "runtimes/bash/lexis.sh"

# Loads 'fr.lex' with fallback to 'en.lex' (explicit here, though 
# "en" is also the default if the third argument is omitted)
if ! lexis_load "lang" "fr" "en"; then
    echo "Error: Failed to load translation files" >&2
    exit 1
fi

CONFIG_FILE="$HOME/.config/aura.conf"

# Defensive fallback message if the key is missing from the .lex file
if [[ ! -f "$CONFIG_FILE" ]]; then
    lexis_get_or_default "cli.error_not_found" "Error: Configuration file '%s' not found." "$CONFIG_FILE" >&2
    exit 1
fi

# Standard lookup with printf interpolation
lexis_get "cli.config_loaded" "$CONFIG_FILE"

Key Technical Details

• Zero External Dependencies: Pure Bash logic relying strictly on associative arrays and parameter expansion.
• Eager Loading + Lazy Caching: Validates file structure on lexis_load(), then caches formatted printf results on demand.
• Two-tier fallback: requested locale + a fallback locale (defaults to "en", but can be set explicitly, e.g. lexis_load "lang" "fr" "pt"), plus fallback strings via lexis_get_or_default.
• Clean Error Handling: Returns proper exit codes (0/1) and routes errors to stderr.

Bash Runtime Source Code:

https://github.com/edgarmasague/lexis/tree/main/runtimes/bash

Requirements: Bash 4.0+ (associative array support required).

Feedback and shell scripting critiques are welcome!

I've written a basic script that makes connecting to my college's WIFI semi automatic. I would like to turn it into a bigger project by adding console prompts that collect and store data, and pull the data out of a file when needed in the future. Even though I have background with programming, I lack the skills to do it because I'm a English Language Teaching student and do the computer stuff as a hobby or something (I also help other open source projects for the love of the game). What am I supposed to research to get the necessary information I need?

The script in question works without any problems and its whole purpose is to open/run necessary windows/applications or scripts to make it easier for me to login to my school's captive portal, login page etc. The script is triggered by a keyboard shortcut. It uses nmcli to do its job.

• Take a look at this run_aws_ssm_get_parameter function below
• To call it I could do something like run_aws_ssm_get_parameter "false" "" "some_param" and it ll run it without a vault user
• Now obviously it kinda sucks that I am passing an empty string to indicate that we dont have an AWS vault user and I have to also memorize the position of the arguments
• One other way would be this? run_aws_ssm_get_parameter --debug=false --parameter_name=some_param? Is this a good idea or a bad idea?
• Mind you all the code written below is written by me manually, no AI no nothing

```bash function run_aws_ssm_get_parameter() { validate_command_available "${FUNCNAME[0]}" "aws" || return 1

validate_arg_min_count "${FUNCNAME[0]}" 3 "$#" "Usage: ${FUNCNAME[0]} <debug> <aws_vault_user> <parameter_name> [additional aws ssm flags]" || return 1

local -r debug="${1:-false}"

local -r aws_vault_user=$2
local -r parameter_name="$3"
shift 3

validate_arg_not_empty "${FUNCNAME[0]}" "debug" "${debug}" || return 1
validate_arg_not_empty "${FUNCNAME[0]}" "parameter_name" "${parameter_name}" || return 1

validate_arg_type_boolean "${FUNCNAME[0]}" "debug" "${debug}" || return 1

local -a flags=(
    "get-parameter"
    "--name=${parameter_name}"
)

flags+=("$@")

[[ "${debug}" = true ]] && log_info "Fetching AWS SSM parameter with parameter_name:${parameter_name}..."

if [[ ! -z "${aws_vault_user}" ]]; then
    if result="$(aws-vault exec "${aws_vault_user}" -- aws ssm "${flags[@]}")"; then
        [[ "${debug}" = true ]] && log_info "AWS SSM parameter with parameter_name:${parameter_name} fetched successfully"
        printf "%s\n" "${result}"
    else
        log_error "AWS SSM parameter fetch with parameter_name:${parameter_name} failed"
        return 1
    fi
else
    if result="$(aws ssm "${flags[@]}")"; then
        [[ "${debug}" = true ]] && log_info "AWS SSM parameter with parameter_name:${parameter_name} fetched successfully"
        printf "%s\n" "${result}"
    else
        log_error "AWS SSM parameter fetch with parameter_name:${parameter_name} failed"
        return 1
    fi
fi

}

function validate_command_available() { validate_arg_min_count "${FUNCNAME[0]}" 2 "$#" "Usage: ${FUNCNAME[0]} <function_name> <command_name>" || return 1

local -r function_name="$1"

local -r command_name="$2"
shift 2

validate_arg_not_empty "${FUNCNAME[0]}" "function_name" "${function_name}" || return 1

validate_arg_not_empty "${FUNCNAME[0]}" "command_name" "${command_name}" || return 1

if ! command -v "${command_name}" &>/dev/null; then
    log_error "${FUNCNAME[0]}: Function "%s" requires "%s" but it was not found on PATH" "${function_name}" "${command_name}"
    return 1
fi

}

function validate_arg_min_count() { local -r function_name="$1"

local -r expected_count="$2"

local -r actual_count="$3"
local -r message="${4:-}"
shift 4

if [[ -z "${function_name}" ]]; then
    log_error "${FUNCNAME[0]}: function_name:${function_name} is required"
    return 1
fi

if [[ -z "${expected_count}" ]]; then
    log_error "${FUNCNAME[0]}: expected_count:${expected_count} is required"
    return 1
fi

if [[ -z "${actual_count}" ]]; then
    log_error "${FUNCNAME[0]}: actual_count:${actual_count} is required"
    return 1
fi

if [[ ! "${expected_count}" =~ ^[0-9]+$ ]]; then
    log_error "${FUNCNAME[0]}: expected_count must be a non-negative integer, got: %s" "${expected_count}"
    return 1
fi

if [[ ! "${actual_count}" =~ ^[0-9]+$ ]]; then
    log_error "${FUNCNAME[0]}: actual_count must be a non-negative integer, got: %s" "${actual_count}"
    return 1
fi

if [[ "${actual_count}" -lt "${expected_count}" ]]; then
    if [[ -z "${message}" ]]; then
        log_error "${FUNCNAME[0]}: Function "%s" expected %d argument(s) but got %d" "${function_name}" "${expected_count}" "${actual_count}"
    else
        log_error "${message}"
    fi
    return 1
fi

}

function validate_arg_not_empty() { local -r function_name="$1"

local -r arg_name="$2"
local -r arg_value="$3"
shift 3

if [[ -z "${function_name}" ]]; then
    log_error "${FUNCNAME[0]}: function_name:${function_name} is required"
    return 1
fi

if [[ -z "${arg_name}" ]]; then
    log_error "${FUNCNAME[0]}: arg_name:${arg_name} is required"
    return 1
fi

if [[ -z "${arg_value}" ]]; then
    log_error "${FUNCNAME[0]}: Function "%s" received empty value for argument "%s"" "${function_name}" "${arg_name}"
    return 1
fi

}

function validate_arg_type_boolean() { validate_arg_min_count "${FUNCNAME[0]}" 3 "$#" "Usage: ${FUNCNAME[0]} <function_name> <arg_name> <arg_value>" || return 1

local -r function_name="$1"

local -r arg_name="$2"
local -r arg_value="$3"
shift 3

validate_arg_not_empty "${FUNCNAME[0]}" "function_name" "${function_name}" || return 1

validate_arg_not_empty "${FUNCNAME[0]}" "arg_name" "${arg_name}" || return 1
validate_arg_not_empty "${FUNCNAME[0]}" "arg_value" "${arg_value}" || return 1

case "${arg_value}" in
true | false) ;;
*)
    log_error "${FUNCNAME[0]}: Function '%s' expected 'true' or 'false' for argument '%s', got: %s" "${function_name}" "${arg_name}" "${arg_value}"
    return 1
    ;;
esac

} ```

I am building a shell framework with a series of commands and subcommands for task-managing, habit-tracking...

Within those, there is a collection of flags that hold different meanings:

• -d Duration, Date...

• -n Name, Note...

• -l Link, Length...

Should I use different letters for different meanings even if they belong to different commands?

I want a real bash-user's opinion, not just the AI's advice.

I personally think that it isn't that big of a deal.

But let me know what y'all think.

Thanks!

```bash

https://linux.die.net/man/8/usermod

function install_docker() { validate_arg_min_count "${FUNCNAME[0]}" 3 "$#" "Usage: ${FUNCNAME[0]} <debug> <version> <user>" || return 1

local -r debug="${1:-false}"
local -r version="$2"

local -r user="$3"
shift 3

validate_arg_not_empty "${FUNCNAME[0]}" "debug" "${debug}" || return 1
validate_arg_not_empty "${FUNCNAME[0]}" "version" "${version}" || return 1
validate_arg_not_empty "${FUNCNAME[0]}" "user" "${user}" || return 1

validate_arg_type_boolean "${FUNCNAME[0]}" "debug" "${debug}" || return 1

if dnf install "docker-${version}" \
    --assumeyes \
    --quiet; then
    [[ "${debug}" = "true" ]] && log_info "docker installation successful $(docker --version)"
else
    log_error "docker installation failed"
    return 1
fi

if usermod --append --groups docker "${user}"; then
    [[ "${debug}" = "true" ]] && log_info "adding user:${user} to the docker group successful"
else
    log_error "adding user:${user} to the docker group failed"
    return 1
fi

if newgrp docker; then
    [[ "${debug}" = "true" ]] && log_info "changes to docker group successful"
else
    log_error "changes to docker group failed"
    return 1
fi

if systemctl enable docker.service &&
    systemctl start docker.service; then
    [[ "${debug}" = "true" ]] && log_info "starting docker service successful"
else
    log_error "starting docker service failed"
    return 1
fi

}

Install docker-compose

Don't use chmod u+x here since it runs as root

https://github.com/amazonlinux/amazon-linux-2023/issues/1032#issuecomment-3674146092

function install_docker_compose() { validate_arg_min_count "${FUNCNAME[0]}" 2 "$#" "Usage: ${FUNCNAME[0]} <debug> <version>" || return 1

local -r debug="${1:-false}"
local -r url="$2"
shift 2

validate_arg_not_empty "${FUNCNAME[0]}" "debug" "${debug}" || return 1
validate_arg_not_empty "${FUNCNAME[0]}" "url" "${url}" || return 1

validate_arg_type_boolean "${FUNCNAME[0]}" "debug" "${debug}" || return 1

if curl \
    --location "${url}" \
    --output "/usr/local/bin/docker-compose" \
    --show-error \
    --silent; then
    [[ "${debug}" = "true" ]] && log_info "Download for docker-compose successful, version:$(docker-compose --version)"
else
    log_error "Download for docker-compose failed"
    return 1
fi

if chmod +x /usr/local/bin/docker-compose; then
    [[ "${debug}" = "true" ]] && log_info "Permission grant to execute docker compose by ec2-user successful"
else
    log_error "Permission grant to execute docker compose by ec2-user failed"
    return 1
fi

}

function install_git() { validate_arg_min_count "${FUNCNAME[0]}" 2 "$#" "Usage: ${FUNCNAME[0]} <debug> <version>" || return 1

local -r debug="${1:-false}"
local -r version="$2"
shift 2

validate_arg_not_empty "${FUNCNAME[0]}" "debug" "${debug}" || return 1
validate_arg_not_empty "${FUNCNAME[0]}" "version" "${version}" || return 1

validate_arg_type_boolean "${FUNCNAME[0]}" "debug" "${debug}" || return 1

if dnf install "git-${version}" \
    --assumeyes \
    --quiet; then
    [[ "${debug}" = "true" ]] && log_info "git installation successful $(git --version)"
else
    log_error "git installation failed"
    return 1
fi

}

function install_jq() { validate_arg_min_count "${FUNCNAME[0]}" 2 "$#" "Usage: ${FUNCNAME[0]} <debug> <version>" || return 1

local -r debug="${1:-false}"
local -r version="$2"
shift 2

validate_arg_not_empty "${FUNCNAME[0]}" "debug" "${debug}" || return 1
validate_arg_not_empty "${FUNCNAME[0]}" "version" "${version}" || return 1

validate_arg_type_boolean "${FUNCNAME[0]}" "debug" "${debug}" || return 1

if dnf install "jq-${version}" \
    --assumeyes \
    --quiet; then
    [[ "${debug}" = "true" ]] && log_info "jq installation successful $(jq --version)"
else
    log_error "jq installation failed"
    return 1
fi

}

```

• Some of them are doing literally the same thing like installing git and jq and yet others in the name of installing are doing slightly different stuff
• There is also a tonne of validation checks everywhere. Not sure if there is a better way to put that along with the debug stuff