Help with regex, I think?

Here is what I'm working with so far:

#!/bin/bash

# 1942_stu_ovl.png
# 1942_udb_ovl.png
# 1943_stu_ovl.png
# 19xx_bp_ovl.png
# 2020bb_bp_ovl.png
# 3wonders_bp_ovl.png
# aerofgt_bp_ovl.png
# airbustr_bp_ovl.png
# aliensec_bp_ovl.png
# aliens_udb23_nono6493_edit_ovl.png

games=()

while read -r png; do
    game="$(basename "${png%%_*}")"
#    [[ "$game" =~ ${games[*]} ]] || \
    games+=("$game")
done < <(find . -type f -name "*.png" | sort -u)

echo "${games[@]}"

If I run this as-is, I get output with the duplicate games listed twice (1942 1942 1943 (...) xybots zaxxon zaxxon). If I uncomment the [[ "$game" =~ ${games[*]} ]] || \ line, I get no output at all. What I want is each game listed once (1942 1943 19xx (...) xevious xybots zaxxon).

Ultimately I'm trying to build .cfg files with one-or-more .png's defined for each one, but right now I'm still trying to get a unique list of game names.

The ending config files would look such as -- zaxxon_ovl.cfg:

overlays = 3

overlay0_overlay = "./zaxxon_bp_ovl.png"
overlay0_full_screen = true
overlay0_descs = 0

overlay1_overlay = "./zaxxon_stu_ovl.png"
overlay1_full_screen = true
overlay1_descs = 0

overlay2_overlay = "./zaxxon_udb_ovl.png"
overlay2_full_screen = true
overlay2_descs = 0

The only thing it needs to do is count the PNG's and list them -- the full_screen and descs values are always constant. Any ideas?

https://redd.it/zbbn0k
@r_bash

what this shell command mean: wait $${!} ?

Hello, I found this line of shell noscript in a docker-compose file.

/bin/sh -c 'while :; do sleep 36000 & wait $${!}; nginx -s reload; done & nginx -g \\"daemon off;\\"'

Could you guys explain me what it does? I know it overrides the default CMD used in the Nginx Dockerfile to start the Nginx server and I know its purpose is to wait for another service called "certbot" that generates and signs certicates thanks to Letsencrypt and saves these certs in a shared folder /etc/certache/certs. But I dont see how ? especially I dont understand those characters : $${!}

The docker-compose file in question:

/////////
web:
    image: nginx:1.23
    container_name: nginx
    restart: always
    ports:
      - 80:8080
      - 443:8443
    volumes:
      - ./nginx-templates:/etc/nginx/templates
      - ./certcache/certs:/etc/certcache/certs:ro
    environment:
      - NGINX_HOST=${DOMAIN_NAME}
      - PMA_HOST=phpmyadmin
      command: "/bin/sh -c 'while :; do sleep 36000 & wait $${!}; nginx -s reload; done & nginx -g \"daemon off;\"'"
    depends_on:
      - phpmyadmin
      - certcache
//////

Thanks you !

https://redd.it/zbj15f
@r_bash

Need help with parameter expansions in my CLI tool.

I'm trying to debug my CLI tool ([https://github.com/membersincewayback/gen](https://github.com/membersincewayback/gen)) and address unset variables, however I just realized one of my parameter expansions isn't working how I thought it was supposed to as below:

#!/usr/bin/env bash
FILENAME="${!#}"
EXT="${FILENAME##*.}"

The intention is to set `FILENAME` to the last argument (working) and `EXT` to anything following the final "." (not working as expected). The problem is, if there is no "." it sets `EXT` == `FILENAME` which has undesired effects on the rest of the noscript. (i.e. creates possible conflict if `FILENAME` matches an existing template.)

Any help would be appreciated!

https://redd.it/zbjpo5
@r_bash

making menu: some doubts about the best way I'm doing it. Am I right? Is there a better way to do this?

Hi,

I'm making a noscript with a big menù for config my homeserver (see the code at the end of post)... now I'm questioning myself if there is a better way to write the menu. Questions are:

1. the `INITIAL_MANDATORY_SERVER_CONFIG_MENU` list, could be written in a different place, for example in the constraints part of the noscript, at the beginning? It seems no..
2. `INITIAL_MANDATORY_SERVER_CONFIG_MENU` could be written in a different way, for example `INITIAL_MANDATORY_SERVER_CONFIG_MENU=( "INIZIALIZZA" "INSTALL AND UPGRADE STABLE SOURCES" ...)` ? It seems no...
3. Otherwise, should I organize the menu in a complete different way?

thanks for any advice.

​

​

INITIAL_MANDATORY_SERVER_CONFIG_MENU=(
"INIZIALIZZA"
"INSTALL AND UPGRADE STABLE SOURCES"
"INSTALL NEW STABLE SOFTWARES"
"INSTALL DOCKER + DOCKER-COMPOSE"
"CREATE USERS"
"CONFIG WIREGUARD ADMIN"
"CONFIG WIREGUARD HOME"
"CONFIG WIREGUARD PARENTS"
"CONFIG SERVER RSYNC"
"CONFIG CRON JOBS"
"CONFIG NetworkUpsTools"
"CONFIG COCKPIT"
"RACKNERD VPS MANAGEMENT SCRIPTS"
"CREATE SWAPFILE"
"LAST GLOBAL CONFIGs"
)
PS3='CHOOSE INITIAL_MANDATORY_SERVER_CONFIG_MENU_VOICE: '
select INITIAL_MANDATORY_SERVER_CONFIG_MENU_VOICE in "${INITIAL_MANDATORY_SERVER_CONFIG_MENU[@]}"
do
case $INITIAL_MANDATORY_SERVER_CONFIG_MENU_VOICE in

https://redd.it/zc775q
@r_bash

Command not found

When I try to use `date = ($date)` it says that the "command was not found". This is also the case for other commands like pwd and whoami. Anyone know whats up?

https://redd.it/zcj8rl
@r_bash

How to create a bashrc url fetch noscript?

I'm complete noob when it comes to shell and i'm learning so please tolerate me xD

i already have a alias set to download with yt-dlp and wget but can somone write me a noscript that i could put in my bashrc so i can just put the url without any alias in the terminal and start downloading like for example if i use https://youtu* it would start using yt-dlp and if i put https://** if would start using wget??


Thank you!

https://redd.it/zcoav5
@r_bash

Need some help with a ffmpeg bash noscript

This is what I have:

#!/usr/bin/env bash

set -e
mkdir -p $HOME/Videos/WhatsPrep 2>/dev/null || true

for i in "$@"; do output=$(ls "$@" /path/glob | tr '\n' '\0' | xargs -0 -n 1 basename); ffmpeg -hide_banner -y -i "$i" -c:v libx264 -c:a aac -filter_complex scale=w=-2:h=720 -crf 24 -movflags +faststart -pix_fmt yuv420p "$HOME/Videos/WhatsPrep/${output%.*}.mp4"; done

What I'm trying to do is to let ffmpeg convert multiple files which are in different locations. However they create a single file with a filename which contains all output filenames. What am I doing wrong?

https://redd.it/zcri87
@r_bash

How can I write something into a file on an non-interactive shell?

I am relatively new to bash. I am trying to write something into a file using bash and Java.

In the interactive mode it works fine.

echo "Hello World" > new_file

But when I am, e.g. trying to execute this with help of the Java runtime nothing happens.

runtime.exec('echo "Hello World" > new_file');

doesn't work, while

runtime.exec('touch new_file');

works just fine.

Why is that and how can I make it work? Thanks in advance!

https://redd.it/zd1fnt
@r_bash

What is @SOMETHING@ assigned to variable

Trying to read a bash noscript and I'm baffled with this construction. Never seen that before. Can some1 explain that to me?

https://redd.it/zd1rnx
@r_bash

quotes from command output are treated as literal characters?

i'm trying to build a noscript that opens a dialog box with radio buttons, each button being assigned a name. these names can contain spaces, so obviously i try to quote the output from the array which contains the names.

when i run my current attempt, being

for n in ${!list@}; do
printf "$n "
printf "\"${list$n}\" "
done

it works as intended. it outputs the index of the name, followed by the name itself, in quotes.

giving it list=(test1 test2 "test 3") outputs 0 "test1" 1 "test2" 2 "test 3" which is exactly what i need.

so when i wrap this in a nice $() and use that as arguments for kdialog (or a quick testing noscript that loops through all cli arguments) i would expect the shell to treat the quoted parts as single arguments, rather than treating the quotes as literal characters. so when i make a noscript "test.sh" which contains

#!/usr/bin/bash
for item in $@; do
echo $item
done

and run it like this /test.sh $(for n in ${!list[@]}; do printf "$n "; printf "\"${list[$n]}\" "; done) i would expect to see

0
"test1"
1
"test2"
2
"test 3"

as output but instead i get

0
"test1"
1
"test2"
2
"test
3"

which leads me to believe that the shell is treating the quotes as literal. which sounds an awful lot like it's designed that way.

so is this supposed to happen? and is there a way around it?

i've already checked, single quotes don't work either.

https://redd.it/zd7axm
@r_bash

Help with homebrew and bash

Hi everyone, I've changed my shell to the homebrew bash after installing homebrew in zsh. When I use "brew" it tells me that the command is not found. Is there some way to use both the homebrew bash and also be able to access homebrew while inside that bash?
Currently I am using the /opt/homebrew/bin/bash and it will not allow me to use the “brew” command.

Thank you!

https://redd.it/zdfrfp
@r_bash

I trained an AI to understand and fix command-line errors

https://redd.it/zeafv1
@r_bash

Bash syntax - why?

Hi folks,

I just came across the bash syntax for a switch statement. It's... surprising.

Are there any resources online that explain how this syntax came to existence, and why it is still in use today?

https://redd.it/zeepuh
@r_bash

Hey y’all i’m super new to bashing and i’m curious on where to start. I know nothing about bash but i was going to ask if y’all have any resources to help me get started with it? thank you!



https://redd.it/zem5a0
@r_bash

Here’s a playlist of 7 hours of music with NO VOCALS I use to focus when I’m coding /learning . Post yours as well if you also have one!

Spotify | Apple | Youtube | Amazon

https://redd.it/zelzee
@r_bash

Replace hostname

Hi All,

I am planning to replace existing hostname by making simple interactive noscript

#!/bin/bash
echo "Set Hostname"
read name1
name='cat /proc/sys/kernel/hostname'
sed -i 's/$name/$name1/g' /etc/hostname
hostname $name1

The issue here is - it changes hostname. I exit and log back in. I see new hostname. But nothing gets changed in /etc/hostname file. reboot and I am back to old hostname.

​

What am I missing here?

https://redd.it/zexcn4
@r_bash

Finding a 5 digit code for a locked zip file

As the noscript states, I am looking to create a noscript that goes through 0 to 99999 and once it finds the right code it unlocks and unzips the contents. I know the use of a for loop and it will be slow but that's nothing to worry about for my noscript. The locked file is using 7-zip.

https://redd.it/zey4h8
@r_bash

Reading stdin of a parent process from within a child process?

# edit: Excellent solution by oh5nxo

{
coproc {
while read -sn1 -u3 line # original stdin
do
echo "coproc got $line" >&4 # original stdout
done
}
} 3<&0 4>&1 # hackery to "ship" stdin and stdout into coprocess
while sleep 1
do
echo "toplevel doing other things"
done

[https://www.reddit.com/r/bash/comments/zeyt4f/comment/iz9el4q/?utm\_source=share&utm\_medium=web2x&context=3](https://www.reddit.com/r/bash/comments/zeyt4f/comment/iz9el4q/?utm_source=share&utm_medium=web2x&context=3)

# Objective:

Reading `stdin` of the parent process ongoing from within a coproc child process.

* Can't use root
* Can't block the parent process
* Can't use `read` in the parent process because even if it's not blocking for long it's very messy and defeats the purpose of having an unhindered co-running process (see: `read` examples below).

# What I have:

ParentPid=$$
coproc {
exec 1>/proc/$ParentPid/fd/1 2>/proc/$ParentPid/fd/2
printf '\n%s\n' 'COPROC reading...' 2>&1
while true; do
read -n 1
printf 'KEY: >%q<\n' "$REPLY"
done
}

# Output should look like:

...the following when `asdf` is typed or sent into `stdin` of the parent process:

KEY: >a<
KEY: >s<
KEY: >d<
KEY: >f<

# Example output if something isn't working:

asdf

# Solutions that don't work:

/dev/stdin>/proc/$!/fd/0
# bash: /dev/stdin: Permission denied

/dev/stdin>&"${COPROC[1]}"
# bash: /dev/stdin: Permission denied

/proc/$$/fd/0>&"${COPROC[1]}"
# bash: /proc/13852/fd/0: Permission denied

# ___Inside coproc process___
exec /proc/$ParentPid/fd/0>&0
/bin/bash: line 3: exec: /proc/16449/fd/0: cannot execute: Permission denied

Works but blocks the parent process:

while true; do
read -s -n 1
echo -n "$REPLY" >&"${COPROC[1]}"
done

Works but it's sloppy, can leak text onto the tty and lags input if "do other things" takes too long:

while true; do
read -s -t 0.1 -n 999
echo -n "$REPLY" >&"${COPROC[1]}"
# do other things
sleep 0.5
done

Completely at the end of my rope on how to solve this, any help is greatly appreciated.

Big thank you,

https://redd.it/zeyt4f
@r_bash

what is this? !::=::\

Running env in bash in cygwin terminal shows this in my environment variables and I am ashamed to say I don't have any idea what it does or what it's for:

!::=::\

Any ideas?

https://redd.it/zf48j3
@r_bash

I'm preparing for the LPIC-1 exam and I cannot figure out why the correct answers to this question are the marked ones. Can someone help me?
https://redd.it/zf6nte
@r_bash

Why is the output in a different order?

declare -A beatles
beatles=(
singer=John
bassist=Paul
drummer=Ringo
guitarist=George
)

# Loop as written in the O'Reilly book

for musician in singer bassist drummer guitarist
do
echo "The ${musician} is ${beatles$musician}."
done
echo

# My way

for i in "${!beatles@}"
do
printf '%s\n' "The $i is ${beatles${i}}."
done

https://redd.it/zf7g2o
@r_bash