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

Hello guys! Im writing to here with the last hope. Im doing my first semester in uni and I have to write a bash noscript and I cant do it, I’Ve seen a lot of videos but I just simply dont understand it. I have 15 hours to make it so please, if anyone can help, help!

My homework is called Letter/Email Script (idk whice one, im not native english).
The denoscription to is:
“The program runs in the background and monitors incoming mail, if the subject of the mail is a certain pre-specified text (argument), then the
takes the contents of the letter as the sh shell noscript, executes it, and captures its output and sends it back to the sender. Don't disturb others during rehearsals”

I translated the dinoscription with google so Idk how accurate is it. :(

https://redd.it/zfdik9
@r_bash

I'm writing a file manager in pure BASH

https://redd.it/zfiqrq
@r_bash

Losing my mind trying to add to my startup noscript

Hi folks! I am working on setting up Robot Operating System on Ubuntu 22.04LTS. I need to add an echo line to my startup noscript, so that when I open my terminal it will automatically run a source command to setup the source for ROS.

I can't figure out how to do this - i've just been told that stuff about ~/.bashrc, which I opened in vim. I looked at it and i don't see where I would add the echo line. If anyone can provide advice, or point me towards a helpful resource, I'd greatly appreciate it.

Thanks in advance!

https://redd.it/zfh9p0
@r_bash

Spoof MAC address to random Apple vendor and Change to random IP according to current network ID

# CREATED BY: Zerodark875
# PROOF OF CONCEPT

if [[ $(id -u) -ne 0 ]]; then
echo "Need root. Quiting."
exit 1
fi

if [[ -z ${1} ]]; then
echo "Usage: ${0} [network_device]\nExample: ${0} eth0"
exit 2
fi

net_dev=${1}
current_ip=$(ip addr show ${net_dev} | grep -w inet | awk -F' ' {'print$2'} | cut -f1 -d'/')
network_id=$(echo ${current_ip} | awk -F'.' {'print$1"."$2"."$3'})
current_mac=$(ip link show ${net_dev} | grep -w ether | awk -F" " {'print $2'})
apple_mac_addresses=$(macchanger --list=Apple | cut -f3 -d" " | awk {'if ($1 != ""){print$1}'})
apple_mac_address_length=$(wc -l<<<${apple_mac_addresses})
picked_apple_mac_address=$(expr $(expr ${RANDOM} % ${apple_mac_address_length}) + 1)
vendor_id=$(echo ${apple_mac_addresses} | awk -v line=${picked_apple_mac_address} -F" " {'print$line'})

final_mac_address="${vendor_id}:$(expr $(expr ${RANDOM} % 89) + 10):$(expr $(expr ${RANDOM} % 89) + 10):$(expr $(expr ${RANDOM} % 89) + 10)"
final_ip="${network_id}.$(expr $(expr ${RANDOM} % 254) + 1)"

echo "Generating new ip and Mac address with Apple as vendor ID ;)"
echo "Current IP: ${current_ip} Current MAC: ${current_mac}"
echo ${final_ip} ${final_mac_address}

echo -n "Apply changes to the machine? (N/y):"
read choice
c=$(awk {'print tolower($0)'} <<< ${choice})
if [[ ${c} == "y" ]]; then
echo "Changing mac address to ${final_mac_address}"
ip link set ${net_dev} down
macchanger -m ${final_mac_address} ${net_dev}
ip link set ${net_dev} up
echo "Mac address changed. Waiting 5 seconds for new IP from DHCP server then we change it again"
sleep 5
current_ip=$(ip addr show ${net_dev} | grep -w inet | awk -F' ' {'print$2'} | cut -f1 -d'/')
echo "Deleting current IP ${current_ip}"
ip addr del ${current_ip}/24 dev ${net_dev}
echo "Adding new IP ${final_ip}"
ip addr add ${final_ip}/24 dev ${net_dev}
fi

https://redd.it/zfreok
@r_bash