Exact timing of $PS0 and $BASHCOMMAND

I've had this line at the bottom of my ~/.bashrc for a while:

trap 'test "$BASHCOMMAND" == "$PROMPTCOMMAND" && printf "\e]2;$PWD\a" || printf "\e]2;$BASHCOMMAND\a"' DEBUG ;;

It uses a DEBUG trap to print the running command ($BASHCOMMAND) to the terminal emulator's title bar or else print the working directory ($PWD) if nothing is executing. I know some terminal emulators do this for you, but my favorite (urxvt) does not.

This has worked very well for me, but I recently learned about the $PS0 prompt, which is also run before the command executes, like a DEBUG trap, and I thought it might be a better way to implement this same thing.

It doesn't seem to be working, though, and I think the issue is in the timing of when $PS0 is shown and when $BASHCOMMAND is updated. When I add:

PS0="[\e]2;$BASHCOMMAND\a\]"

in my ~/.bashrc, the string in the terminal's title bar does update, but it's always one command behind (and the first is an odd test command). Is there any solution to this, like a way to update the $BASHCOMMAND sooner or an alternative way to get the command (from readline maybe?).

Or is the way I've already been doing this with the DEBUG trap likely still the best? I've always wondered how inefficient that is. It's all builtins, so I would hope not very, but I'm not too sure.

https://redd.it/1s4cx2x
@r_bash

Functions from my bashrc

My list of functions has gotten pretty long, thought maybe I'd share, [as asked](https://www.reddit.com/r/bash/comments/1s3lo2t/comment/ocgkhi1/). Share some interesting functions of your own, or any feedback you think I could use.

\>> [bashrc excerpt gist](https://gist.github.com/ekipan/1c2e5a6164fbe7601b32e089d889994c), and [permalink at time of post](https://gist.github.com/ekipan/1c2e5a6164fbe7601b32e089d889994c/adac6cb830131238a3666390d7574ec8a95f15be)

# a few of them:
e() { echo >&2 "$@"; "$@"; } # echo and run
hl() { bat -Ppl "${1:-help}"; } # highlight eg: find --help | hl
iftty() { if [[ -t "$1" ]]; then "${@:2}"; else cat; fi; }
opts() { iftty 0 "$@" --help |& rg "^\s*-" | hl; } # eg: opts find
# see gist for the rest.

A few I use _constantly_: gits() h() opts(). A ps1() that puts a newline if the last command didn't, so my prompt is on the left margin while scrolling back. A bit of whimsy like q() that I [adapted from a reddit post](https://www.reddit.com/r/zsh/comments/1rs6gcn/). I like the interface I designed for the path() function but since I only used it exactly once in my bashrc I just took it back out.

My style is definitely a lot more dense and nongeneric than most people or LLMs would like, but I own these functions and dense, direct code is better IMO.

**Background:** After my old Windows Thinkpad started getting a bit sick, I switched to using my Steam Deck as my main PC, with a dock, TV, and bluetooth keyboard. It seems a pretty good Arch flavor, and I wasn't entirely new to Linux, but I've learned a lot. One pain point is lack of manpages, so one of the first things I put in my .bashrc was a bunch of aliases to open my browser or curl from <https://cheat.sh>.

I had a ten-year-old account ended up shadowbanned, presumably because I posted a bashrc excerpt with URLs in it, maybe also because I'd forgotten about the account for years, idk. Thus the pastebin: I'm wary of posting too much code directly.

https://redd.it/1s3u7f5
@r_bash

-x () { local -; set -x; "$@"; }

Exhibit A in the case for "some kludges are good kludges".

https://redd.it/1s3lo2t
@r_bash

Could someone please review my scripting and give me criticism?

I made a script to manage my dotfiles on linux (arch btw).
Link to repo
https://codeberg.org/Flan-Angel/Dawtfiles/src/branch/main

Link to script
https://codeberg.org/Flan-Angel/Dawtfiles/src/branch/main/PushToSYS.sh


Tysm if you do end up checking it out :)

https://redd.it/1s42scy
@r_bash

passgen — Bash password generator (DB-safe, TUI)
https://redd.it/1s6uxiv
@r_bash

Terminal Native API Testing Tool is LIVE!

https://preview.redd.it/gq2fehb401sg1.png?width=1233&format=png&auto=webp&s=84566c1673098db1088664090ad091e0c01a3a0d


Hey guys!

Rust based API Testing Tool is now live,

# Y'all can download it from here: Volt


This is a minimalistic API testing tool right in the terminal itself which has a blazingly fast response window. It scans source files and lists every route instantly — axum, express, fastapi, next.js, and more so that you do not need to write the Endpoints or Base URLs manually.

Do check it out and let me know your thoughts.

The Binaries are available for MacOS, Linux, and Windows on the website. Feel free to drop issues if you find any.

https://redd.it/1s72ksw
@r_bash

A Week of Letting Bash Handle Everything
https://voidrane.substack.com/p/a-week-of-letting-bash-handle-everything

https://redd.it/1s7hej3
@r_bash

AI written in BASH? It exists!

Someone actually created an AI (GPT) in BASH!

https://github.com/ResonantEntropy/bashGPT

It is not a wrapper around curl.. It's a full GPT!

LOL! This is intense!

https://redd.it/1s8hiwa
@r_bash

Caption yourself
https://redd.it/1s8t00n
@r_bash

for loop not indexing stuff in the {}'s

i can make a for loop like this

for i in {1..13} ; do
    echo $i
done

and get each value for the index printed on a separate line

but if i let len=13

and try a loop like this

for i in {1..$len} ; do

    echo $i

done

i get this output

{1..13}

is there no way to use a shell variable within the {}'s of a for loop?


https://redd.it/1sdcz2j
@r_bash

Free online editor where you can write Bash scripts, run them, take notes, and export to PDF
https://redd.it/1sd0v1g
@r_bash

Clean WhatsApp messages

MYNAME="Homer Simpson" sed -E "s/^[[^]]+] ${MYNAME}: //" | sed -E "s/^[^]+] ^:+: /> /"

# Before

17:09, 4/5/2026 Homer Simpson: Nuclear plant back online!
17:09, 4/5/2026 Mr. Burns: Thank you for this. Who are you again?
17:10, 4/5/2026 Homer Simpson: Homer Simpson, sir 😅

# After

Nuclear plant back online!
> Thank you for this. Who are you again?
Homer Simpson, sir 😅

https://redd.it/1sdjuja
@r_bash

This Website is Built with Bash
https://bash-wasm.ysap.sh

https://redd.it/1scdwid
@r_bash

tool for helping me find commands

I've struggled a lot moving to linux from windows, and one of the things that has been a thorn in my side has been forgetting what commands to use, what they are called, and how to use them correctly.

Today I made myself this little tool to make life easier so I don't have to scroll through loads of 'man' pages just getting more confused. It's not a professional tool by any means, it was literally just made this morning to solve a basic problem, but I figured if it's useful for me it's probably useful to others too.

I am not great at linux, at software, at git, or anything like some people here, so don't tear me apart just because my tool sucks. I am aware. But it made my life easier, and i hope it will help others who are struggling.

https://github.com/koryfargodev/mytools

https://preview.redd.it/e3ezellgk7tg1.png?width=656&format=png&auto=webp&s=5446c86e4d8968a52859aa29ac328db7e68a1d96

https://redd.it/1scf9ss
@r_bash

Is using $SHLVL a good way to tell if a script is running in a terminal window?

So, I want to make it so that a script I'm running will ONLY run in a terminal emulator window, and will sleep for 3 seconds then exit if it's not in a terminal emulator window. I've done a little bit of looking, but I'm not entirely sure if it would work as I intend, and if there are ways in which it could fail/if there are more reliable methods.i was thinking of something along the lines of:

If $SHLVL > 1 then
Echo running in terminal
Echo continuing
Elif $SHLVL =< 1 then
Sleep 3
Exit
Else
Echo how is this even possible?
Fi

(Obviously that's not correct syntax, it's just the general structure/idea of what I want to do) I'm not at my PC rn (on a road trip) but I'm trying to write a general test script on my phone that I can test on my PC once I return home.

Edit: to clarify I should mention that I'm on Debian x86_64, and when I say "in a terminal window" I mean that it's running with stout and sterr being displayed on a terminal emulator window, and stdin being read from the terminal emulator window.

https://redd.it/1schwjv
@r_bash

Why does grep .* skip . and .. in ls -a output?

Let me clarify the situation first. As we know `ls -a` shows all files including `.` (current directory) and `..` (parent directory).

And If we want to print only the hidden files excluding `.` and `..` . We can run `echo .[!.]*` , and we can also use `ls -A | grep .*` it will not look as clean as `echo .[!.]*` but works. and I used `-A` because it already excludes `.` and `..` .

But i suppose If I run `ls -a | grep .*` , shouldn’t it also show `.` and `..`? But It doesn’t, those two entries are missing as if I'm using `-A` .

Am I misunderstanding how `grep .*` behaves here?

Be kind please even if it's something obvious, the noob is still learning.

https://redd.it/1sbuopd
@r_bash

How declarative can bash scripts get?

I'm doing sanity testing of containers using bash and wonder how close I can get bash to the testing workflow of tools like Playwright.

For example. Here is my current script for 1 sanity test

#!/bin/bash
set -euo pipefail


PASS=0
FAIL=0
GREEN='\0330;32m'
RED='\033[0;31m'
RESET='\033[0m'


ok() {
echo -e " ${GREEN}[PASS${RESET} $"
((++PASS))
}
fail() {
echo -e " ${RED}[FAIL]${RESET} $"
((++FAIL))
}

echo ""
echo "=== 1. Container status ==="
if podman inspect "$CONTAINER" --format '{{.State.Running}}' 2>/dev/null | grep -q true; then
ok "Container '$CONTAINER' is running"
else
fail "Container '$CONTAINER' is NOT running"
fi

Here's my first attempt at making it more declarative:


describe() {
echo ""
echo "--- $1 ---"
}


it() {
local title=$1
shift
if "$@"; then ok "$title"; else fail "$title"; fi
}

containerisrunning() {
podman inspect "$CONTAINER" --format '{{.State.Running}}' 2>/dev/null | grep -q true
}


describe "Container"
it "container '$CONTAINER' is running" podman inspect "$CONTAINER" --format '{{.State.Running}}' 2>/dev/null | grep -q true


Ultimately, i'm not going to go with the second style since it it's not that readable. I can't pass the function body as an arugment as you'd do in JS and the alternatives (eval) will make the code worse.

Before I chuck this whole concept down, I thought I'd make a post and see if thats really impossible in Bash, or I may be missing something.



https://redd.it/1sahl6s
@r_bash

cURL file upload patterns - multipart, batch uploads, xargs, and piping from stdin

Kept re googling the same cURL commands for uploading files, so I put everything in one place.

Covers:
\- Basic upload with -F
\- Auth headers and API keys
\- Looping through a directory
\- Parallel uploads with xargs
\- Piping tar output directly into an upload endpoint
\- What -F, -H, -X, -o, and --max-time actually do
\- Common errors like 413, 401, and 400, plus how to fix them

https://filepost.dev/blog/how-to-upload-files-with-curl

Hopefully this saves someone else the same trial and error.

https://redd.it/1sdvw2w
@r_bash

Best learning resource

Dear Linux administrators, how did you learn bash and bash scripting and what are the best ways you’ve used bash in enterprise environments? Give some examples of how you’ve used bash in server side scripting, infrastructure operations and automation and tell us what resources did you use to learn as a beginner to get to where you are now?

https://redd.it/1sdz4k9
@r_bash

Shell function for installing/removing packages using fzf!

A shell function for removing/installing packages from AUR, system repos and flatpak mainly only using fzf as dependency. Should work with most Arch Linux based distros(I am on CachyOS and works perfectly) if you have fzf, yay installed and AUR enabled :)

mngpkg() {
    local selections=$( (
        yay -Slq | awk '{print "[yay-ins] " $1}' &
        flatpak remote-ls flathub --columns=application | awk '{print "[flt-ins] " $1}' &
        pacman -Qq | awk '{print "[yay-rm] " $1}' &
        flatpak list --app --columns=application | awk '{print "[flt-rm] " $1}' &
        wait
    ) | fzf --multi --header 'Search All Repos & Installed Apps (Tab to select)' \
            --preview '
                tag=$(echo {} | awk "{print \$1}");
                pkg=$(echo {} | awk "{print \$2}");
                if [ "$tag" = "[yay-ins]" ]; then
                    yay -Si "$pkg"
                elif [ "$tag" = "[yay-rm]" ]; then
                    pacman -Qi "$pkg"
                elif [ "$tag" = "[flt-ins]" ]; then
                    flatpak remote-info flathub "$pkg"
                elif [ "$tag" = "[flt-rm]" ]; then
                    flatpak info "$pkg"
                fi
            ' )

    [ -z "$selections" ] && return

    local yay_in=$(echo "$selections" | grep '^\[yay-ins\]' | awk '{print $2}')
    local flat_in=$(echo "$selections" | grep '^\[flt-ins\]' | awk '{print $2}')
    local yay_rm=$(echo "$selections" | grep '^\[yay-rm\]' | awk '{print $2}')
    local flat_rm=$(echo "$selections" | grep '^\[flt-rm\]' | awk '{print $2}')

    if [ -n "$yay_rm" ] || [ -n "$flat_rm" ]; then
        printf "Delete app data and configuration files for removed packages? (y/N): "
        read -r delete_data
    fi

    if [ -n "$yay_rm" ]; then
        if [[ "$delete_data" =~ ^[Yy]$ ]]; then
            echo "$yay_rm" | xargs -ro sudo pacman -Rns
        else
            echo "$yay_rm" | xargs -ro sudo pacman -Rs
        fi
    fi

    if [ -n "$flat_rm" ]; then
        if [[ "$delete_data" =~ ^[Yy]$ ]]; then
            echo "$flat_rm" | xargs -ro flatpak uninstall --delete-data
        else
            echo "$flat_rm" | xargs -ro flatpak uninstall
        fi
    fi

    if [ -n "$yay_in" ]; then
        echo "$yay_in" | xargs -ro yay -S
    fi

    if [ -n "$flat_in" ]; then
        echo "$flat_in" | xargs -ro flatpak install flathub
    fi
}

https://redd.it/1se2jym
@r_bash

Added piping support to my open source 3D viewer
https://redd.it/1se632c
@r_bash