Grep question about dashes

Im pulling my hair out with this and could use some help. Im trying to match some strings with grep that contain a hyphen, but there are similar strings that dont contain a hyphen. Here is an example.

echo "test-case another-value foo" | grep -Eom 1 "test-case"
test-case
echo "test-case another-value foo" | grep -Eom 1 "test"
test
I dont want grep to return test, I only want it to return test-case. I also need to be able to grep for foo if needed.

https://redd.it/1hk9edb
@r_bash

Array lengths - this works but the traditional method doesn't

Any ideas? The first one works, The second one doesn't in a noscript, doing a test from the command prompt all is good. Its a simple list of numbers all <100 , array length < 10

len="$(echo "${nlist[@]}" | wc -w)" # Good
len="${#nlist@}" # Bad

https://redd.it/1hkn7gw
@r_bash

Multiple coprocs?

I have a use case where I have to execute several processes. For the most part, the processes will communicate with each other via CAN, or rather a virualized vcan0.

But I also need to retain each process's stdin/out/err in the top-level management session, so I can see things each process is printing, and send commands to them outside of their normal command and control channel on vcan0.

Just reading up on the coproc command and thought it sounded perfect, but then I read what is essentially the last line in the entire bash man page:

There may be only one active coprocess at a time.

Huh? How's come? What's the best practice for juggling multiple simultaneously running programs with all I/O streams available in a way that's not going to drive me insane, if I can't use multiple coprocs?

https://redd.it/1hkven3
@r_bash

Bash is getting pretty

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

pure-bash-bible alternative?

Since pure-bash-bible Got archived, is there any viable alternative for it? I know bash but I don't remember every little thing like reversing an array.

I want to have bash cheatsheet.

https://redd.it/1hjvy3m
@r_bash

I give up bash.

There is a structured way to learn every stupid programming language but not bash. There are textbooks with exercises, leetcode like problem solving series. but not for bash. Maybe, it is because one is expected to copy paste stuffs while doing bash.

I've taken many many bash noscripting courses, but fk those courses. Courses teach you nothing. What you want is a structured problem solving approach.


I want to build something. I can;t do it without chatgpt. Learning to build with chatgpt is like learning to fly before learning to walk.

I ask in forums, but they are similar lke chatgpt in the sense that they provide you solution. And believe me, nobody who has got solutions to their programming problems from forums has ever learnt programming by asking. Ask a few more and people think you're a spammer.

I am learning java and bash noscripting/shell noscripting since a year. I can can see visible progress in java where I have outgrown myself before year. But bash, oh fck. I can't tell the syntax of array looping without chatgpt/google. I've to look up google for even the minor of the things.


This is because I have got nothing to practice. I don't want to be a prompt master that copies stuffs from chatgpt or google. Copying isn't bad, but when you haven't even build a muscle memory to declare an array there is when things go south.


Should I even tell what I am trying to build in bash?

Let me go ahead.

I've a csv file with 2 columns separated by a comma.



U-DLCI,6
C/R,1
EA,1
L-DLCI,4
FECN,1
BECN,1
DE,
EA,1

Like this, now I want to go through them one by one.

U-DLCI is 6, so I allocate 6 unit of distance for it. And print U-DLCI inside it center justified.

C/R is 1, so I slloate 1 unit of distance for it and print C/R inside it.


EA is 1 so I do ....

Now, the sum of past three numbers was 8.

So, I jump to a new line.


Then L-DLCI is 4 so I print it in a 4 units of distance at the center.

and so on....
Had I learnt file handling in java, this is a no-brainer in java. But bash, ffck whtat is this? How can a language be so deceptive?

https://redd.it/1hla31k
@r_bash

Guys, which platform would you recommend me to learn bash noscripting?



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

Convert JSON array to bash array

Hi guys,

I am a linux noob and am trying to write a noscript to extract info from a mkv file using mkvmerge but am not able to convert the target json noscript to a bash array. I have tried a number of solutions from stack overflow but with no success.

here are some of my attempts

dir="/mnt/Anime/Series/KonoSuba/Season 2/[Nep_Blanc] KonoSuba II 10 .mkv"
*********************************************************************************
ARRAY_SIZE=$(mkvmerge -J "$dir" | jq '.tracks | length')
count=0
arr=()

while [ $count -lt $ARRAY_SIZE ];
do
arr+=($(mkvmerge -J "$dir" | jq '.tracks'[$count]))
((count++))
done
*********************************************************************************
readarray -t test_array < <(mkvmerge -J "$dir" | jq '.tracks')
for element in "${test_array[@]}";
do
echo "$element"
done

*********************************************************************************
array=($(mkvmerge -J "$dir" | jq '.tracks' | sed -e 's/^\[/(/' -e 's/\]$/)/'))

but the echo prints out lines instead of the specific objects.

Though now it is helpling me with my python, originally the project was to help me learn bash noscripting. I would really like to have a bash implementation so any help overcoming this roadblock would be appreciated.

https://redd.it/1hm27y2
@r_bash

Tools to edit modified/createdAt infos about a file based on its name?

I have a bunch of files, and more or less their name can be categorized into these categories:

.trashed-1737661897-video20241213152336.mp4
.trashed-1737661969-IMG20241217205925.jpg
1675865719503..jpg
20190207063809.jpg
20200830202505.jpg
FBIMG1574447155845.jpg
IMG-20190622-WA0006.jpg
IMG20200724114950442.jpg
VID20240623230607.mp4
ReactNative-snapshot-image8923079110072067694.png
Screenshot20241212082715Chrome.jpg
originalbadf21d1-5c56-43a1-b19a-82f5d43de9beIMG20220707155608.jpg
video20240720102400.mp4

The problem is that their "created at" or "modified at" date are set to today. Do you know any tools that might help me change their dates based on their name?

https://redd.it/1hm2z2r
@r_bash

how to exit noscript gracefully

**how to handle these exception in the bash noscript :**

* when pressing `ctrl + c` to exit the noscript it just exit the current running process in the noscript and move to next process. instead of exiting the entire noscript. how to handle it ??

* How should a noscript handle the situation when its terminal is closed while it is still running ??

* what is the best common code / function which should be present in every noscript to handle exception and graceful exiting of the noscripting ??

if you wish you can also dump your exception handling code here
**feel free for any inside**
i would really appreciate your answer ; **thanks :-)**

https://redd.it/1hn07dy
@r_bash

Tuifoop, a terminal game in Bash
https://redd.it/1hn2md5
@r_bash

Time bucket

Hello,

I am building a small noscript to analyse the log of my online app and find IP's with a bad pattern to exclude them through a reverse-proxy or firewall rule. I have been successfull that far to identify the "bad IP's" but I would like to manage what I would call "time buckets" (apologies if this is not correct, English is not my mother tongue, neither is bash) before I exclude them. For instance, if an IP address appears 5 times in 1 minute, I exclude it.

This is what I started to write, but I meet problems I don't understand and can't get any further.

#!/bin/bash

CONTAINER='my_app'

TEMP_FILE='/home/eric/monitoring/temp'

LOG_FILE=$(docker inspect "$CONTAINER" | grep 'LogPath' | cut -d '"' -f4)

declare -A OCCUR
declare -A HOUR

tail -F "$LOG_FILE" | while read LINE; do
IP=$(echo "$LINE" | grep -Po "([0-9]{1,3}[\.]){3}[0-9]{1,3}" | head -n 1 | grepcidr -v '10.0.0.0/8' | grepcidr -v '127.0.0.0/8' | grepcidr -v '172.16.0.0/12' | grepcidr -v '192.168.0.0/16')
if [ -n "$IP" ]
then
if [ -z $OCCUR["$IP"] ]
then
OCCUR["$IP"]=0
fi
OCCUR["$IP"]=$(OCCUR["$IP"])+1
HOUR["$IP"]=$(date)
echo "$OCCUR[$IP]" " ; " "$HOUR[$IP]" >> "$TEMP_FILE"
fi
done

I get this "log" in return

./surveillance.sh: ligne 20: OCCUR[<suspect-ip-address>] : commande introuvable
./surveillance.sh: ligne 20: OCCUR[<suspect-ip-address>] : commande introuvable
./surveillance.sh: ligne 20: OCCUR[<suspect-ip-address>] : commande introuvable
./surveillance.sh: ligne 20: OCCUR[<suspect-ip-address>] : commande introuvable
./surveillance.sh: ligne 20: OCCUR[<suspect-ip-address>] : commande introuvable
./surveillance.sh: ligne 20: OCCUR[<suspect-ip-address>] : commande introuvable

And this temp file (my check)

[<suspect-ip-address>] ; [<suspect-ip-address>]
[<suspect-ip-address>] ; [<suspect-ip-address>]
[<suspect-ip-address>] ; [<suspect-ip-address>]
[<suspect-ip-address>] ; [<suspect-ip-address>]
[<suspect-ip-address>] ; [<suspect-ip-address>]

Any clue how I should go about that ?

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

Manage buckets

Hello,

I am building a small noscript to analyse the log of my online app and find IP's with a bad pattern to exclude them through a reverse-proxy or firewall rule. I have been successfull that far to identify the "bad IP's" but I would like to manage what I would call "time buckets" (apologies if this is not correct, English is not my mother tongue, neither is bash) before I exclude them. For instance, if an IP address appears 5 times in 1 minute, I exclude it.

This is what I started to write, but I meet problems I don't understand and can't get any further.

#!/bin/bash

CONTAINER='my_app'

TEMP_FILE='/home/eric/monitoring/temp'

LOG_FILE=$(docker inspect "$CONTAINER" | grep 'LogPath' | cut -d '"' -f4)

declare -A OCCUR
declare -A HOUR

tail -F "$LOG_FILE" | while read LINE; do
IP=$(echo "$LINE" | grep -Po "([0-9]{1,3}[\.]){3}[0-9]{1,3}" | head -n 1 | grepcidr -v '10.0.0.0/8' | grepcidr -v '127.0.0.0/8' | grepcidr -v '172.16.0.0/12' | grepcidr -v '192.168.0.0/16')
if [ -n "$IP" ]
then
if [ -z $OCCUR["$IP"] ]
then
OCCUR["$IP"]=0
fi
OCCUR["$IP"]=$(OCCUR["$IP"])+1
HOUR["$IP"]=$(date)
echo "$OCCUR[$IP]" " ; " "$HOUR[$IP]" >> "$TEMP_FILE"
fi
done

I get this "log" in return

./surveillance.sh: ligne 20: OCCUR[<suspect-ip-address>] : commande introuvable
./surveillance.sh: ligne 20: OCCUR[<suspect-ip-address>] : commande introuvable
./surveillance.sh: ligne 20: OCCUR[<suspect-ip-address>] : commande introuvable
./surveillance.sh: ligne 20: OCCUR[<suspect-ip-address>] : commande introuvable
./surveillance.sh: ligne 20: OCCUR[<suspect-ip-address>] : commande introuvable
./surveillance.sh: ligne 20: OCCUR[<suspect-ip-address>] : commande introuvable

And this temp file (my check)

[<suspect-ip-address>] ; [<suspect-ip-address>]
[<suspect-ip-address>] ; [<suspect-ip-address>]
[<suspect-ip-address>] ; [<suspect-ip-address>]
[<suspect-ip-address>] ; [<suspect-ip-address>]
[<suspect-ip-address>] ; [<suspect-ip-address>]

Any clue how I should go about that ?

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

Do you prefer most of your bash functions to just do a thing, and then not mess with retuning something to a caller?

It seems like the easiest thing to do is to simply just not mess with trying to set some return value to be captured by the caller. yes, I see stuff like this. However, it appears that bash leans more toward getting something done instead of checking that it was in fact done. And seems like very few, in bash, create a bunch of functions that have an interdependency on each other. I.e. seems like it’s just easier to just do logging in functions and manually check that for execution correctness, if desired, for debug etc.

Anybody else feel this way? Am I off my rocker?

https://redd.it/1hmx02r
@r_bash

Color non-printing escape sequence in Bash prompt

Hello,

Rewriting my bash prompt and I realize I completely forgotten the minutae of how to handle ANSI escape sequences for colors within variables within functions within PS1. Here's what I have to start with (it doesn't work):

RED='\e[38;5;203m'
GREEN='\e[38;5;41m'
RESET='\e[0m'

function prompt_status() {
 # Set prompt color
 if [ $? -ne 0 ]; then
  PROMPT_COLOR=$RED
 else
  PROMPT_COLOR=$GREEN
 fi
}

PROMPT_COMMAND=prompt_status

PS1="$PROMPT_COLOR$ $RESET"

I've been going over the Bash manual again to review expansions, etc. But I'm stuck. I've tried curly-braces, the dollar sign infront of the single-quoted escape sequence, the \[ \] trick. None work. Does anyone have a good resource for learning about why this chunk of noscript doesn't work? And what is the recommended way to go about noscripting colors for prompts? I really want to set my colors in environment variables for readability and so that I can use matching colors across Bash, Zsh, Fish and Tmux.

Thanks

NOTE: (I'm running Bash version 5.2.37 on Terminal.app with xterm-256 enabled. Colors show up fine when I use printf or echo, but not for my PS1 variable)

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

I'm making bash fishing game and echos dont work correctly because of backslashes

echo " "
echo " |\ o"
echo " | \/|\"
echo "~~~|~~/\"
echo " | "
echo " ⤿ "

so how can i fix it
i just want to make backslashes display in echo


(btw sorry for my terrible english)

https://redd.it/1ho7y6s
@r_bash

I made a shell ai copilot
https://redd.it/1hoviz1
@r_bash

new to bash ,made a doom scrolling breaker over 4 days

https://preview.redd.it/fr7utt9flt9e1.png?width=949&format=png&auto=webp&s=ce7f0319961978574f41db669313e8da81a48e8e

https://preview.redd.it/sk6f4dwklt9e1.png?width=982&format=png&auto=webp&s=cc6952c112245898edf1104fe27ea867e2f9c76a



https://redd.it/1hp0i9r
@r_bash

-t 0 for testing terminal not working as expected

In window manager (Sway) I bind the following:

bindsym $mod+5 exec -t 0 && notify-send "run from terminal"

and it reports it runs from terminal even though it's running from a keybinding executing the command.

I'm also using this check and it's not working as expected when running the noscript from status bar calling the command to the noscript.

Why might this be the case? My attempt is to determine whether to run fzf (cli) or dmenu (gui-equivalent) depending on whether it's run from the terminal. Can this be done reliably?

https://redd.it/1hp5v2d
@r_bash