wrote my first bash noscript today!

It is a very beginner noscript, which I hope to work on even more. My goal is to some how have my noscript start up on the end of a docker run command and automatically port forward my chosen ports so I can access the WUI on my host machine. Also trying to find a way to find system IP and store it in a variable in the bash noscript.

My noscript

# ! /bin/bash

read -p “what port?: “ PORT

echo “you chose $PORT “

read -p “tcp or udp?: “ PROTOCOL

echo “port forwarding $PORT/$PROTOCOL “

sudo ufw allow $PORT/PROTOCOL

sudo system restart ufw

https://redd.it/z1htfc
@r_bash

What's a terminal and what can I do with it? Note I'm asking this while already using it daily as a dev. But I still have 0 conceptual understanding of how computers are designed further down...

It's all so random if you're self-taught. You have 1000s of beginner videos but nobody explains to you what the hell this thing actually is deep down there. When the first terminal or when the first shell (whatever that is) was built, what was it supposed to solve?

Why do we have bash, zsh, and so on? Why do they all feel the same but are still different somehow?

What does it really do? If I echo something is it stored anywhere? What is stored when how? Can I create functions with it? Is what I write in the terminal turning complete? If not why not?

And whatever I have not asked, please just explain this damn thing :)

https://redd.it/z1r0kb
@r_bash

Should I care about how things break?
https://redd.it/z1ykk6
@r_bash

for loop in bash

how do i insert i into the awk statement:

for i in 3 4 5 6 7 8 9 10
do
awk -F',' '{sum+=$i;} END{print sum;}' crimedata-australia.csv

done

https://redd.it/z21j7r
@r_bash

noscript to install latest ImageMagick from source; covers all the bases

Wanted to share this noscript that I use when standing up VMs of mine that do some image processing. It curls the latest ImageMagick source code archive from imagemagick.org, verifies archive integrity, compiles, installs, and double-checks that it's working. Lots of sanity checks throughout.

Suggestions on technicalities, best practices, and aesthetics all welcome! Either here or via the gist.

https://gist.github.com/timoteostewart/16624088e656d336a2a862778788378a

https://redd.it/z28b01
@r_bash

Extracting a date from a variable

So I am making this one noscript where information are stored inside of another file and I want to take out just the date portion of each line that has an appointment. So far, I have this

`while read line`
`do`
`lineDate=\`echo $line | cut -c4-13\` #returns only the calendar date of the current line`
`done`

This works okay for the format of my lines in the file which look like this:
1| 22/11/2022 Doctor 12:30:00 - 14:00:00

However, once my appointment count reaches double or triple digits, then the cut will not be accurate anymore since the extra digits are moving the line forward a bit. Rather than reformat all the lines forward, anticipating the many digits. Is there a way for me to use sed to extract the date only? So from line one, lineDate would equal 22/11/2022. I am not sure of the format to use for this as I want ##/##/####.

https://redd.it/z2egl8
@r_bash

Homework questions.

Yes homework questions are allowed, but do remember the point of homework is for ***YOU*** to learn the material not us.
Here are some guidelines on how to get the best answer to help you learn.

**What we like:**

* Provide full context. Don't just drop a question without details.
* Tell us exactly what you need to solve and what information you've been given.
* Include any specific restrictions given by your professor.
* If you can't get yourself started, that's OK, but do tell us and we will see if we can get you going without just spoon feeding you. It really is better for you and better for everyone.
* Tell us what you've tried already, it will help with explaining the best future direction.
* Make a start on solving it, share your code and what errors you are seeing. *Share error messages exactly.*


**What we don't like:**

* "Do it for me, with complete explanation please"
* URGENT, DUE IN 15 MINUTES, or other phrases in ALL CAPS.
* People who delete their question once they get an answer.

**When you share code, do it in a way that works for everyone.**

* Share code, not pictures of code. We don't want to work from a screenshot or a photo of a terminal.
* If your noscript is longer than 30 or so lines, it might be better to share it via a code service like github or via a pastebin.
* Shorter noscripts or code snippets can just be included in your post.
* When you paste code into your question, ideally don't use the 'fancypants' editor because the code will be broken for users of old reddit.
* When you use 'markdown' mode or old.reddit then please leave 1 blank line before your noscript and 4 spaces before each line to get the correct formatting.
* Try running your code through shellcheck before (link in sidebar) it will catch many errors and offer suggestions for common problems and might save you some time.

https://redd.it/z2gzzi
@r_bash

Filling username & password through noscript

To use my college wifi, I have to open the auth. page and fill the username & password everytime.

I want to automate it such that the noscript open the site & fill the username & password and submit it by itself.

How can I achieve this?

https://redd.it/z2mblv
@r_bash

Delete last 3 lines of file

I'm trying to find a quick/dirty way to just delete the last lines from a file without opening it. So for example, something similar to this:

$cat test
first line
second line
third line
forth line
fifth line
$ head -n -3 test > test2
$ cat test2
first line
second line

Like this works, but now I've got to delete test and mv test2 into test. This whole process is just far too cumbersome.

I tried using the below, but unfortunately it results in test being empty. It appears to be an order of operations issue where it is trying to overwrite a file it's trying to get data from, and ends up with test having a completely empty file.

$ head -n -3 test > test

What I need is some sort of buffer to hold the output of $ head -n -3 test, which can then be used as an input buffer for a file. Not really sure how to do that.

https://redd.it/z2nc8m
@r_bash

Hi again!

Thanks for the help in advance. Today I looked for some until loops again, however, I got a bit confused between the while and the until loop.

Here is my while loop:

read -r -p "Please insert your number 1 -10: " number

while $number -le 10
do
echo "Your number is $number."
number=$(( number+1 ))
done

Here below is my until loop:

read -r -p "Please insert your number 1 -10: " number

until $number -eq 10
do
echo "Your number is $number."
number=$(( number+1 ))
done

Still not pretty sure the differences between them. Kindly asking if someone would have more information and explain it, please. Really appreciate it guys!

https://redd.it/z2lyhw
@r_bash

lobash: a modern, safe, powerful library for Bash noscript development

## What is Lobash?

Due to its complex syntaxes with symbols, and Unix commands are different in platforms such like BSD and GNU utilities have different options and behaviors with same command name, Bash noscript development is complex and fallible.

Javanoscript has a powerful library Lodash for simplifying development. So I build Lobash to do similar works for shell development.

Lobash provides collections of functions to improve efficiency of shell development. It is compatible with Bash 4.0+ and MacOS/Linux/Alpine/Busybox systems.

It is implemented with pure bash noscript.

## Features

* Modular and easy to use. One module one Function.
* Semantic functions instead of recondite bash expressions, substitutions, expansions.
* Rich Functions. Over 120+ modules provided.
* Robust and Safe. Over 700+ test cases tested. Tested in Linux and MacOS with Bash 4.0\~5.2.
* Fast. 0.058s to load Lobash completely.
* Compatible with MacOS/Linux/Alpine/Busybox systems.
* Compatible with Bash 4.0 and higher versions.

\------

Today it released v0.5.0. If you like it, please click the Star button. Thank you.

[https://github.com/adoyle-h/lobash](https://github.com/adoyle-h/lobash)

https://redd.it/z2vgfi
@r_bash

grep: warning: stray \ before /

I am trying to run this noscript.

#!/bin/sh


movie=$(curl -s https://1337x.to/search/$query/1/ | grep -Eo "torrent\/0-9{7}\/a-zA-Z0-9?%-/" | head -n 1)
magnet=$(curl -s https://1337x.to/$movie | grep -Po "magnet:\?xt=urn:btih:[a-zA-Z0-9]" | head -n 1)
peerflix $magnet -l -v


I get the error of grep: warning: stray \\ before / . I have tried to get rid of the \\ before the /. This did not work. Can anyone help me?

https://redd.it/z2vfx0
@r_bash

How to pass an associative array to another noscript

I want to pass an associative array in noscript1.sh to noscript2.sh. Here is what I have:

noscript1.sh:

declare -A queues
queues=( "key1"="value1" "key2"="value2" "key3"="value3" "key4"="value4" )

call noscript2:
noscript2.sh "$param1" "$param2" "$param3" "${queues@}"

noscript2.sh:

arg1=$1
arg2=$2
arg3=$3
declare -A arg4=$4

The associative array in noscript1 is fine. I can loop through the array and see its elements. However, when I tried to pass it to noscript2.sh, I can't see any of the elements in arg4. Thanks in advance.

https://redd.it/z2xyv5
@r_bash

Need help with sed and variables

Hi Everyone,

I've put together a sed for vnstat xml output for my openwrt router. (trying to get a cleaner output) My sed works if I have the year (2022) and month (11) in the sed command. When I replace 2022 with $y and 11 with $m, it doesnt work, no change in the output, like it doesn't recognize it.

​

The file looks like this:

2022 11 21 05:00 474322562 15172268
2022 11 21 06:00 536016232 651897033
2022 11 21 07:00 184569685 109642704

Here is what works (without the variables, just normal ):

vnstat --xml |grep -hnr "hour id" | sed "s/<^>>/ /g; s/2022//g; s/ //g; s/ 00/:00/g; s/11 /11-/g" | cut -d " " -f2- > houroutput.xml

-----------------------------------------------
and the output looks good:
11-21 05:00 474322562 15172268
11-21 06:00 536016232 651897033
11-21 07:00 184569685 109642704

&#x200B;

my noscript looks like with the variables in sed, I even replaced the single quotes with double, but no change in output.

#!/bin/sh
y="date +%Y"
m="date +%m"

vnstat --xml |grep -hnr "hour id" | sed "s/<[^>]>/ /g; s/$y//g; s/ //g; s/ 00/:00/g; s/$m /$m-/g" | cut -d " " -f2- > houroutput.xml

Output doesnt look good:
2022 11 21 05:00 474322562 15172268
2022 11 21 06:00 536016232 651897033
2022 11 21 07:00 184569685 109642704

https://redd.it/z31cfq
@r_bash

Somewhat probably generic post

What's your personal 'ah ha' moment when getting into learning bash? What made you think, "oh damn I need to know this"

https://redd.it/z3riln
@r_bash

my first semi noob noscript - Loop through list of trackers and test if they are alive using nc
https://gist.github.com/neuthral/0ff41380958321d69888fead29d510ee

https://redd.it/z3rcka
@r_bash

read contents of a file into a variable with bash without invoking other commands?

Is there some internal bash way to do this?

x=$(cat /proc/uptime)

And i am not thinking about the line-by-line "while read l; do bla bla; done < file" (for various reasons).

https://redd.it/z3ue97
@r_bash

I've been working on this CLI tool to automate creation of noscript files, modification of file permissions, and input typical text. I spend a lot of time in the command line for work, but consider myself still learning noscripting. If you have any input I'd appreciate it!
https://redd.it/z4hi9r
@r_bash

Sorting by size with ls -S and reading each first line of .txt files

So i have this task to sort .txt files by size and then reading the first line of each of them and displaying them

i do know that i can sort by size with ls -S

also for the reading and displaying part

for i in *.txt; do head -n 1 $i; done

problem is that if i put ls -S | before this ... it doesnt work .. like i get the output but its not sorted by size

i do know that there is an awk command, tried with that either, but i cant use it as its for class and we just started with bash so we have to stick to the .. "basics"

https://redd.it/z4mvws
@r_bash

Having trouble with a bash user creation noscript for homework

The bash noscript pulls some stuff out of a csv file (firstname, lastname, dob, group)

I can get that stuff into an array, but when I try to massage the data in the array, it tries to run one of the variables as a command.
Can someone tell me what I'm doing wrong?




\#!/bin/bash

\#set -x

testdata="/home/diana/testdata.csv"

declare -a fnames

declare -a lnames

declare -a dob

declare -a course

while IFS="," read -r Student_Firstname Student_Lastname Student_BirthDate Course_Data trash;

do

fnames+=("$Student_Firstname")

lnames+=("$Student_Lastname")

dob+=("$Student_BirthDate")

done<$testdata

\## usernames[index\]= ${fnames[index\]::1}${lnames[index\]} | tr [:upper:\] [:lower:\]

for index in "${!fnames[@\]}";do

\#this next line tries to "run" the username.
usernames= "${fnames[index\]::1}${lnames[index\]} | tr [:upper:\] [:lower:\]"

\# echo ${fnames[index\]::1}${lnames[index\]} | tr [:upper:\] [:lower:\]

\# echo ${fnames[index\]::1}${lnames[index\]::1}${dob[index\]} | tr [:upper:\] [:lower:\]

\# echo $usernames

\#printf ${fnames[index\]}

done

https://redd.it/z4niaz
@r_bash

Cron job for shell noscript not running

https://stackoverflow.com/questions/74577211/cron-job-for-shell-noscript-not-running

Full/detailed q in stack overflow above.

tl;dr cannot get my cron job to successfully execute a shell noscript, nor can I seem to get it to format as intended, despite the noscript working when called manually and absolute paths used for everything.

https://redd.it/z4mj18
@r_bash