Guys, I need help with this assignment. No chat GPT
https://redd.it/1fgqcgg
@r_bash

If you pipe a list of files, what bash command do you pipe it to, for it to move those files to another directory?

E.g. ls | mv ... what?

https://redd.it/1fgtg88
@r_bash

Why is the output getting mixed up? I've done tons of troubleshooting but nothing has worked. I followed a noscript from a textbook so I expected it to just function, and not reverse the order of the numbers. I can tell it has to do with the third period but can't tell why or how.

https://redd.it/1fh13d2
@r_bash

How to check if background while loop exits early?

I have a bluetooth dmenu noscript that enables the service then prompts me to select devices to connect. I have my devices auto-connect when service is enabled. I want to make it smarter--when a device connects within 3 seconds (they usually auto-connect practically instantly), do not show prompt and quit the noscript early when device connects, else show it and continue on with noscript further prompting the user.

It seems I need a while loop in the background to start counting for the timeout, right? I have something like this:

# ... code to enable bluetooth

# background while loop
declare -i i=0 timeout=3

# quit loop early if there are connected devices
while (( i <= timeout )) || (( ${#devices_connected[@]} )); do
i+=1
sleep 1
done &

pid=$!

# ... code to get `devices_connected`, expected to run as soon as
# background while loop starts so it can start seeing connected devices

if wait "$pid" && (( i < 2)); then
echo "exit now"
exit
else
echo "continue with noscript"
fi

Is this even the right approach? The code doesn't work because `i` is modified within while loop so it value is not kept.

https://redd.it/1fh5r93
@r_bash

I need help I don't know why /home/minecraft doesn't include all the files

#!/bin/bash



# Defining variables

PROJECT_ID="alexuni2"

VM_NAME="minecraft-server"

DISK_NAME="minecraft-disk2"

IP_NAME="mc-server-ip"

NETWORK_NAME="minecraft-network"

REGION="us-central1"

ZONE="us-central1-a"

BUCKET_NAME="minecraft-backup"

MINECRAFT_DIRECTORY="/home/minecraft"

SERVER_JAR_URL="https://launcher.mojang.com/v1/objects/d0d0fe2b1dc6ab4c65554cb734270872b72dadd6/server.jar"



# Set the project ID for gcloud commands

gcloud config set project $PROJECT_ID



# Step 1: Create the VPC with automatic subnetting

echo "Creating VPC with automatic subnetting..."

gcloud compute networks create $NETWORK_NAME --subnet-mode=auto --project=$PROJECT_ID



echo "Creating Cloud Storage Bucket..."

gsutil mb -l $REGION -p $PROJECT_ID gs://$BUCKET_NAME/



# Step 2: Create a static external IP address

echo "Creating static external IP..."

gcloud compute addresses create $IP_NAME --region=$REGION --project=$PROJECT_ID



# Step 3: Create the VM Instance with a blank disk and external static IP

echo "Creating VM instance."

gcloud compute instances create $VM_NAME \\

--zone=$ZONE \\

--machine-type=e2-medium \\

--network=$NETWORK_NAME \\

--tags=minecraft-server \\

--boot-disk-size=10GB \\

--boot-disk-type=pd-ssd \\

--boot-disk-device-name=$DISK_NAME \\

--address=$IP_NAME \\

--no-service-account \\

--no-scopes \\

--metadata=startup-noscript-url=https://storage.googleapis.com/cloud-training/archinfra/mcserver/startup.sh,\\

shutdown-noscript-url=https://storage.googleapis.com/cloud-training/archinfra/mcserver/shutdown.sh \\



echo "Attaching additional 50 GB SSD disk..."

gcloud compute instances attach-disk $VM_NAME \\

--disk=$DISK_NAME \\

--zone=$ZONE \\

--project=$PROJECT_ID



# Step 4: Create the Firewall Rules

echo "Creating firewall rules..."

gcloud compute firewall-rules create minecraft-allow-ssh \\

--direction=INGRESS \\

--priority=1000 \\

--network=$NETWORK_NAME \\

--action=ALLOW \\

--rules=tcp:22 \\

--source-ranges=0.0.0.0/0 \\

--project=$PROJECT_ID



gcloud compute firewall-rules create minecraft-allow-internal \\

--direction=INGRESS \\

--priority=1000 \\

--network=$NETWORK_NAME \\

--action=ALLOW \\

--rules=all \\

--source-ranges=10.128.0.0/20 \\

--project=$PROJECT_ID



gcloud compute firewall-rules create minecraft-allow-icmp \\

--direction=INGRESS \\

--priority=1000 \\

--network=$NETWORK_NAME \\

--action=ALLOW \\

--rules=icmp \\

--source-ranges=0.0.0.0/0 \\

--project=$PROJECT_ID



gcloud compute firewall-rules create minecraft-rule \\

--direction=INGRESS \\

--priority=1000 \\

--network=$NETWORK_NAME \\

--action=ALLOW \\

--rules=tcp:25565 \\

--source-ranges=0.0.0.0/0 \\

--target-tags=minecraft-server \\

--project=$PROJECT_ID



# Step 5: SSH into the VM

echo "SSH into VM: gcloud compute ssh $VM_NAME --zone=$ZONE"



# Step 6: Format and Mount the Disk

echo "Mounting and formatting disk..."

gcloud compute ssh $VM_NAME --zone=$ZONE --project=$PROJECT_ID --command="sudo mkfs.ext4 -F -E lazy_itable_init=0,lazy_journal_init=0,discard /dev/disk/by-id/google-$DISK_NAME"

gcloud compute ssh $VM_NAME --zone=$ZONE --project=$PROJECT_ID --command="sudo mkdir -p $MINECRAFT_DIRECTORY"

gcloud compute ssh $VM_NAME --zone=$ZONE --project=$PROJECT_ID --command="sudo mount -o discard,defaults /dev/disk/by-id/google-$DISK_NAME $MINECRAFT_DIRECTORY"



# Verify the disk is mounted

gcloud compute ssh $VM_NAME --zone=$ZONE --project=$PROJECT_ID --command="df -h"



# Step 7: Install Java, Screen, and Other Packages

echo "Installing Java, screen, and wget..."

gcloud compute ssh $VM_NAME --zone=$ZONE --project=$PROJECT_ID --command="sudo apt-get update && sudo apt-get install -y openjdk-11-jre-headless screen wget"



# Step 8: Download Minecraft Server JAR

echo "Downloading Minecraft server JAR..."

gcloud compute ssh $VM_NAME --zone=$ZONE --project=$PROJECT_ID --command="cd $MINECRAFT_DIRECTORY && sudo wget $SERVER_JAR_URL"



# Step 9:

init the server

echo "initialize the server..."

gcloud compute ssh $VM_NAME --zone=$ZONE --project=$PROJECT_ID --command="cd $MINECRAFT_DIRECTORY && sudo java -Xmx1024M -Xms1024M -jar server.jar nogui && \\

sudo chmod 777 eula.txt && \\

echo "eula=true" | sudo cat > eula.txt && \\"



# Step 10: Start the Minecraft Server in Screen

echo "Starting Minecraft server in a screen session..."

gcloud compute ssh $VM_NAME --zone=$ZONE --project=$PROJECT_ID --command="cd $MINECRAFT_DIRECTORY && sudo screen -dmS mcs java -Xmx1024M -Xms1024M -jar server.jar nogui && \\

sudo screen -d mcs && \\

sudo screen -r mcs"





# Step 11: Create Backup Script

echo "Creating backup noscript..."

gcloud compute ssh $VM_NAME --zone=$ZONE --project=$PROJECT_ID --command="sudo tee $MINECRAFT_DIRECTORY/backup.sh > /dev/null <<EOL

#!/bin/bash

screen -r mcs -X stuff '/save-all\\n/save-off\\n'

/usr/bin/gsutil cp -R ${BASH_SOURCE%/*}/world gs://$BUCKET_NAME-minecraft-backup/\\$(date '+%Y%m%d-%H%M%S')-world

screen -r mcs -X stuff '/save-on\\n'

EOL"



# Step 12: Make the Backup Script Executable

echo "Making backup noscript executable..."

gcloud compute ssh $VM_NAME --zone=$ZONE --project=$PROJECT_ID --command="sudo chmod +x $MINECRAFT_DIRECTORY/backup.sh"



# Step 13: Schedule Backup to Run Every 8 Hours

echo "Scheduling backups every 8 hours..."

gcloud compute ssh $VM_NAME --zone=$ZONE --project=$PROJECT_ID --command="(crontab -l 2>/dev/null; echo '0 */8 * * * $MINECRAFT_DIRECTORY/backup.sh') | crontab -"



echo "Minecraft server setup complete. Network, VM, disk, firewall, and backups are configured."



https://redd.it/1fhvj56
@r_bash

Condition to remove ANSI characters in case of commands following a "|"

In my noscript I have some options that show colored messages.

If I prefix these with "> text.txt" or ">> text.txt" or a "| less" (by the way "less" is already included in these options), the output will also show the ANSI codes used.

I have already experimented with a filter using "sed", but who will unknowingly use the above symbols and commands, how will they have a "clean" output?

Is there a way to let the noscript know that one of the above characters or commands is in use?

https://redd.it/1fi9knc
@r_bash

Bash noscript cannot run JavaScript file with top level await

I am trying to make a systemd timer that runs a noscript every 5 minutes for notifications to my phone based on an api, and I have successfully checked that the timer and the noscript work separately. For some reason, though, whenever I have the systemd timer point to the noscript.sh and run it, and if I do sudo systemctl status noscript.service, it provides an error: await is a reserved word. I suspect this is because it is a top level await, which for some reason bash can't do? The code it runs in the file is node ./noscript.js, and I have debugged everything I can think of. Even trying to put all of my code in an await function and then doing a then catch on it doesn't work.
Any help would be greatly appreciated, and if this is the wrong subreddit please let me know!

https://redd.it/1fij8mc
@r_bash

Dot files management and bashrc for different servers

So, I am trying to use gnu stow to install my dotfiles. This seems to work for most of my config, except for the .bashrc. Here I work with multiple servers and also with my laptop. Thus, I cannot use the same .bashrc for all of them. I am thinking of using multiple files like

.bashrc_s1
.bashrc_s2
...

and some sort of master bashrc with:

if [[ "$(hostname)" == "s1" ]];then
    source .bashrc_s1
...
fi 

is this a good approach? What have you out there tried and got it to work?

https://redd.it/1fio66d
@r_bash

Cucking bored gibbme some linux command line homework

Like practical skills using bash noscripts. Command line tools like find, awk, sed etc. And how am I supposed to learn about sed and awk? What book is best. I am currently in amazon.in and can't find any books lesser than 100$(equivalent).

https://redd.it/1fion5f
@r_bash

Adding spaces in the date command?

SOLVED. I just needed to add single quotes to the format. export day="$(date '+%a, %b %d, %Y')" Thank you for the replies.

I'd like to set `day` as a variable with the following format "Tue, Sep 17, 2024".

I found the codes: export day="$(date +%a, %b %d, %Y)", but I don't understand how to add the padding.

The man page mentions padding with underscores and zeros but I'm clearly not doing it correctly. Ex.: `echo $day -> Tue,0Sep017,02024` `echo $day -> Tue,_Sep_17,_2024`

https://redd.it/1firt7w
@r_bash

I need your opinions on scron (the code written in it)

https://github.com/omarafal/scron

I'm not exactly sure where to post this, I hope this is the right place as I need any feedback I can get on my bash noscripting code.

So as the noscript suggests, I made a cli tool that basically uses cron for scheduling commands but adds a couple of things; logging for the scheduled commands and simplifies the date/time part of cron making it a bit more human-readable.

It's a mix of bash noscripting and python but mostly bash noscripting.

I want to emphasize that cron is already easy to use, the syntax is far from hard by a mile but some people (including myself) took a biiiit of some time to get the hang of it. So I made this in hopes that it would make scheduling commands a bit more easier and quicker I guess. It in no way replaces cron, if you want to make more complex "timing", use cron, this is called "simple cron" for a reason, to schedule things on the go.

Please do go a tiny bit easy on me lol, this is my first time doing something like this or even posting at all. I'm open to any suggestions, feedback, and comments.

https://redd.it/1fix8vy
@r_bash

Merging multiple files into an array when there might not be a trailing \n

I have several text files that I would like to merge into a single array. This works:

arr=$( cat -s foo.txt bar.txt )

But!

When foo.txt (for example) doesn't have a blank line at the end, the first line of bar.txt is added to the last line of foo.txt.

Meaning:

# foo.txt
uno
dos

# bar.txt
tres
quatro

# arr=$( cat -s foo.txt bar.txt )
uno
dostres
quatro

I know that I can do this with multiple arrays, but this seems cumbersome and will be hard to read in the future:

fooArr=$( cat -s foo.txt )
barArr=$( cat -s bar.txt )
arr=( "${foo@}" "${bar@}")

Is there a better way to combine the files with one cat, AND make sure that the arrays are properly delimited?

https://redd.it/1fjl1rv
@r_bash

Opinions sought regarding style: single vs. double quotes

I’m looking for style suggestions on single vs. double quoting. I am not asking about functionality (i.e. when is double quoting necessary). My current style is as follows:

var1=“${foo}/${bar}”
var2=‘this is a string’
var3=“foo’s bar”

All normal strings are single quoted (var1) unless they have an embedded single quote (var3), and all strings that need expansion are double quoted (var2).

This is consistent in my mind, but when I look at lots of bash noscripts written by others, I see that they use double quotes almost exclusively. This is also correct and consistent. Note that I looked at some of my 10-20 year old noscripts and in those days, I was using double quotes for everything.

Is there any good reason for using one style over another, or does personal preference rule?

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

First argument ($1) returning my username instead of what I assign it

Trying to pass an argument to a bash noscript in Cygwin. I kept getting erroneous results, so I started printing the first argument and assigning it to another variable and I see that no matter what I pass into my noscript the value of $1 is "USER=123456" where 123456 is my actual username and my home directory path is /home/123456 and my Winblows home dir is C:\\Users\\123456. I see the output of "set" has a line item "USER=123456" so it seems $1 is printing this set value. I'm not sure if this is specific to Cygwin or my bash configuration. Any suggestions?

https://redd.it/1fk1qyr
@r_bash

GitHub - mdeacey/universal-os-detector: A Bash noscript for universal OS detection
https://github.com/mdeacey/universal-os-detector/

https://redd.it/1fk9mea
@r_bash

ETL automation testing with unix noscripting!

Hi Everyone! What are some good free resources to learn unix noscripting for ETL automation testing?

https://redd.it/1fkdhg8
@r_bash

How can I adjust my PS1 to have time on right side?

Hello,

I have a specific PS1 and I'd like to add a timestamp right adjusted on the right side of the terminal per new shell line. I can easily put \t or \T inline and it works fine but when I try to offset it with a function it blows up and doesn't work. it seems the function just runs once.

#Color codes
Reset="\[\e[0m\]"
Red="\[\e[0;31m\]"
Green="\[\e[0;32m\]"
Blue="\[\033[0;34m\]"
Yellow='\[\033[0;33m\]'

terraform_ws() {
  #Check if .terraform/environment file exists and that we have a terraform executable.
  if [ -f .terraform/environment ] && command -v terraform &> /dev/null; then
    local workspace
    workspace="$(< .terraform/environment)"
    echo "[${Blue}$workspace${Reset}]"
  fi
}

__kube_ps1() {
  if command -v kubectl > /dev/null 2>&1; then
    CONTEXT="$(kubectl config current-context | awk -F'/' '{print $NF}')"
    if [ -n "$CONTEXT" ]; then
      echo "(${Yellow}k8s:${CONTEXT}${Reset})"
    fi
  fi
}

ps1_pre_exec() {
  # Make user@hostname in PS1 colorful. Red if non zero and green if zero.
  if [ $? != 0 ]; then
    echo "${Red}\u@\h${Reset} \w$(terraform_ws) $(__kube_ps1)"
  else
    echo "${Green}\u@\h${Reset} \w$(terraform_ws) $(__kube_ps1)"
  fi
}

ps1_cursor() {
 echo "\n${Yellow}> ${Reset}"
}

update_timestamp() {
  local date_str=$(date +'%Y-%m-%d %H:%M:%S')
  local date_len=${#date_str}
  local term_width=$(tput cols)
  printf "\e[${term_width}s\e[${term_width - ${date_len}}D${date_str}"
}

#Define PS1
PROMPT_DIRTRIM=2
PROMPT_COMMAND='__git_ps1 "$(ps1_pre_exec)" "$(update_timestamp) $(ps1_cursor)"'

all I get is the proper date printed out in the top right on the first go around of a login shell.

Note if I just put on \t where $(update_timestamp) is it works fine. Also PS1 cusor goes to another line and my actuall prompt looks like

eggman@eggman-2455 ~/.dotfiles/link (k8s:tacobell) (master %|u=) [02:50:51]
>

My goal is to have that timestamp on the far right away.

https://redd.it/1fkshv9
@r_bash

Log output of most recent command?

Hey guys, I am working on a cli co-pilot application utilizing chatgpt's api. I am relatively new to bash and to coding as a whole -- this is my first application of any sort of scale.

One of the features I would like to implement is an '--explain-last' flag. The basic functionality is to automatically send the most recent terminal output over to chatgpt to rapidly troubleshoot errors/other problems. Example:

error: ErrorNotFound
$ai --explain-last
This error occurs when you are writing a reddit post and can't think of an error to use as an example.

Although the app does have an interactive mode, this feature is its primary purpose (frankly, to help me learn bash more quickly).

Because terminal output is not stored anywhere on the system, I believe I will have to implement a background service to maintain a last_output.txt snapshot file which will be overwritten each time a new command is issued/output is generated. Because I never know when I will encounter a weird error, I want this process to be entirely frictionless and to integrate quietly behind the scenes.

What is the best way I should do this? Am I thinking about this problem correctly?

Thanks in advance!

Edit: Come to think of it, I will probably send over both the input and the output. Not relevant to this specific task that I am asking about, but maybe a bit more context.

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