I made my first bash script! It opens vim with a file name and a shebang already set!

I've been wanting to get further into bash scripting as I've started using the terminal more and more, so I did some research (shout out to the bash manual (not the one in the epstein files) and YSAP) and took what I know from messing around in python, and made this simple little script:

\#!/usr/bin/env bash

read -p "what is the name of the script? " name

while true; do

if [[ $name == *" "* \]\]; then

echo "please, no spaces."

sleep 3

read -p "what is the name of the script? " name

continue

elif [[ -n "$name" \]\]; then

touch $name

echo '#!/usr/bin/env bash' >> $name

vim $name

else

echo "aight, suit yerself. here's vim with nothing, ig."

sleep 5

vim

fi

break

done

https://redd.it/1sj4fcx
@r_bash

Why doesn’t this Bash script exit even with set -e?

I came across an interesting Bash behavior while experimenting with error handling:

set -e

echo "Starting deployment..."

build_project && deploy_project

echo "Deployment complete"

At first glance, expected that if `build_project` fails, the script should exit immediately because of `set -e`.

But the actual output is:

Deployment complete

From what I understand, `set -e` doesn’t trigger an exit when a failing command is part of a **conditional context** like `&&`, `||`, `if`, etc.

So in this case:

* `false` fails
* But since it’s inside an `&&` chain, Bash treats it as expected control flow
* And continues execution


I’ve been digging deeper into these kinds of edge cases lately (especially from an interview perspective).
If anyone’s interested, I’ve written a more detailed breakdown with examples — happy to share

https://redd.it/1sjdkv5
@r_bash

How to print input if command returns nothing?

I have a command which is supposed to find audio files with no cover image.

What I currently have is

find /srv/media/Music/ -type f -regex '.*\.\(mp3\|flac\|m4a\|opus\)' \
-exec bash -c ' ffprobe -hide_banner -loglevel error \
-select_streams v -show_entries stream=codec_type -of csv=p=0 "$0" \
' {} \;

which gives an output of 'video' if a cover image is attached and no output if no cover image is attached.

How can I expand this so that I get all files with no cover images listed?

I tried to switch STDERR and STDOUT and use a pipe with `$?` to catch this, but couldn't make it work. I always get all the files, not just the ones with no cover image. Command used was `... "$0" 1>&2 | if [[ $? = 0 ]]; then echo "$0"; fi ' {} \;`.

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

I wrote a stupid simple progress bar in pure BASH (source in comments)
https://redd.it/1sjg2di
@r_bash

Cannot use jq to separate in every iteration

Hello!

I need help to put delimiter between pairs of values, like this:
1,a;2,b

or like this:

1,a
2,b

What i have:

[
{
"name": "1",
"argument": "a"
},
{
"name": "2",
"argument": "b"
}
]

What i am doing now to get what i want:

cat file.txt | jq -r -c 'map(.name, .argument) | join (";")'

What is output of this command:

1;a;2;b

Without "join":

cat file.txt | jq -r -c 'map(.name, .argument)

["1","a","2","b"]

Seems like jq thinks that input in one array.

https://redd.it/1sjrr58
@r_bash

Quick help comparing files in two directories?

Long story short, know for a fact that I have duplicates between two directories, but we're talking hundreds of files here and I know at least a few files are in one directory but not the other.

I'd ideally like to have something quickly compare file name & size between the two directories, then spit out the files that are named the same but sized differently, as well as files which are in one directory but not the other.

https://redd.it/1skc8wu
@r_bash

Seeking Practice for Shell Scripting (Specifically POSIX sh / Bash)

Hello everyone !

I’ve been working through some great tutorials (like YouTube : yousuckatprogramming or LearnLinuxTv), but

I’ve hit a wall where I feel like I’m just "passively" absorbing information. I’m currently preparing for a technical school entrance exam so I’m looking for practice cases or problems. (ideally bin/sh or POSIX-compliant bash)

Specifically:

\- Practice Platforms: Are there any sites like DataLemur that have a strong focus on shell scripting ?

\- Real-World Scenarios: For those of you who aren't currently in a DevOps/SysAdmin role, how do you find "mini-projects" to build? I want to move past "Hello World" and into actual file manipulation, parsing, and automation.

My goal is to stop watching and start doing. If you have any "scripts you wish you had when you started" or repos with challenges, please drop them below!

Thanks in advance!

Note: I'm currently on Linux Mint Cinnamon (started using like 1 week ago)...always been a Windows user before.

https://redd.it/1skyhb1
@r_bash

IP Identification Open Source Intel script

This is just a quick script I created because I am constantly having to lookup the information for IP addresses and this one will give you the SOA record for the server the IP is hosted on the whois information for the domain that the IP points as well as the nameservers and a few other relative bits of information. I called it IPID but I feel like there is something similar already out there with the same name so I am not taking credit for the name.

as with any bash script you will need to add it to PATH if you want to use it as a local shell command.


hope someone finds it useful.

https://preview.redd.it/b81ewoinv6vg1.png?width=1033&format=png&auto=webp&s=fce2610c2248e6d61d630e4280714b4b721bfc2a

#!/bin/bash

# Define colors for a cleaner, readable output
GREEN='\0330;32m'
CYAN='\033[0;36m'
RED='\033[0;31m'
YELLOW='\033[1;33m'
NC='\033[0m' # No Color

# Check if an argument is provided; if not, display the usage template
if [ -z "$1" ; then
echo -e "${RED}Error: No IPv4 address supplied.${NC}"
echo -e "Usage: ${GREEN}ipid <ipv4address>${NC}"
echo -e "Example: ${GREEN}ipid 8.8.8.8${NC}"
exit 1
fi

TARGETIP=$1

# Basic IPv4 validation
if ! [ $TARGET_IP =~ ^[0-9{1,3}\.0-9{1,3}\.0-9{1,3}\.0-9{1,3}$ ]]; then
echo -e "${RED}Error: '$TARGETIP' does not look like a valid IPv4 address.${NC}"
exit 1
fi

echo -e "${YELLOW}Gathering intelligence for IP: ${TARGETIP}...${NC}\n"

# 1. Reverse DNS / Hostname
echo -e "${CYAN}+ Hostname & Reverse DNS Lookup${NC}"
if command -v host &> /dev/null; then
host "$TARGETIP"
else
echo -e "${RED}[!] 'host' command not found. Skipping reverse DNS.${NC}"
fi
echo ""

# 2. Server Location, ASN, and ISP Details (via ipinfo.io)
echo -e "${CYAN}[+] Server Location & ISP Details${NC}"
if command -v curl &> /dev/null; then
# Fetching JSON data and displaying it cleanly
curl -s "https://ipinfo.io/${TARGETIP}/json" | grep -v 'readme'
else
echo -e "${RED}! 'curl' command not found. Skipping location details.${NC}"
fi
echo ""

# 3. WHOIS Organization & Network Info
echo -e "${CYAN}+ WHOIS Organization & Domain Info (Summary)${NC}"
if command -v whois &> /dev/null; then
# Grepping the most relevant fields so the terminal isn't flooded with legalese
whois "$TARGETIP" | grep -iE '^(OrgName|Organization|NetName|NetRange|CIDR|Country|StateProv|City|RegDate|Updated|ASName)' | sort -u | head -n 15

# If the summary is empty, the whois server might use different formatting
if [ ${PIPESTATUS[0]} -ne 0 ]; then
echo "Could not parse standard WHOIS summary. Try running 'whois $TARGETIP' manually."
fi
else
echo -e "${RED}! 'whois' command not found. Install 'whois' to see domain registration info.${NC}"
fi
echo ""

echo -e "${YELLOW}Scan complete.${NC}"

https://redd.it/1slf4ua
@r_bash

[Release] I built a bulletproof Screen Time / Parental Control script for Linux Mint (Cinnamon) that fixes the idle-tracking bug.
/r/linuxmint/comments/1slpro5/release_i_built_a_bulletproof_screen_time/

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

Bash script to determine if I have a routable IP address

At my home I have a dynamic IP address which changes at least daily. I have an arrangement with my ISP to always have a routable IP. However, sometimes they mess up and give me a non-routable IP. I would like to be able to detect this from within a shell script so that the shell script can notify me and take other action.

Here's what I'm doing now: I have a remote Raspberry Pi set up with a reverse SSH tunnel to my iMac at home. I can easily detect whether that tunnel is up or not. If it is not up, then it is likely, but not 100% sure, that the cause is a non-routable IP at home. The router at home is a Deco X20.

Is there a better way to determine whether or not my home IP address is routable or not?

https://redd.it/1slznt2
@r_bash

Bash scripts to set up your Yubikey to work with GitHub (OpenGPG, SSH)

https://github.com/andrinoff/yubikey-github


A pretty straightforward guide, as well as 2 automatic scripts, that you can run to set it up for you (could be buggy)

Look forward to contributions!

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

Persistent Sidebar Pane within TMUX that tracks your AI Agent Sessions
https://redd.it/1snrhxc
@r_bash

slate — one command to theme your terminal + prompt + CLI tools in sync (Rust, macOS/Linux)

Built this over the last few months, tagged 0.1.1. One command sets up a coordinated palette across your shell prompt (via Starship), bat, delta, eza, lazygit, fastfetch, tmux, and your terminal emulator (Ghostty/Kitty/Alacritty).
For bash specifically, slate adds a single marker-block to your \~/.bashrc(or \~/.bash_profile on macOS) that sources a managed env file. `slate clean` removes that block cleanly — no orphaned exports, no leftover state.


`cargo install slate-cli` or `brew install MoonMao42/homebrew-tap/slate-cli`

Repo: https://github.com/MoonMao42/slate

Happy to hear feedback on the shell integration — especially the marker-block approach vs alternatives like a standalone rc snippet file.

https://redd.it/1so42dt
@r_bash

I made a Flatpak GUI using Bash + YAD

https://redd.it/1sobuj3
@r_bash

Automate MySQL Backups to S3 with a Pro-Grade Script (And Never Lose Data Again)
https://wgetskills.substack.com/p/automate-mysql-backups-to-s3-with

https://redd.it/1soi17i
@r_bash

Unable to divide string into array

~~~

#!/bin/bash

cd /System/Applications

files=$(ls -a)

IFS=' ' read -ra fileArray <<< $files

#I=0

#while $I -le ${#fileArray[@} ]; do

#echo ${fileArrayI}

#I=$((I++))

#done

#for I in ${fileArray*}; do

#echo $I

#done

#echo $files

~~~

I wrote code to get all of the files in a directory and then put each file into an array. However, when I try to print each element in the array, it only prints the first one. What am I doing wrong?

(The comments show my previous attempts to fix the problem and/or previous code, review them as needed.)

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

If everything works, the script below runs without issues. If something fails, it leaves docker containers running in the background? How do I send an email with the error message if something goes wrong and shut the containers down?


# Context

- AWS RDS is running PostgreSQL 18.1
- EC2 doesnt let you install the latest postgres since the package manager hasnt made it available yet
- So running a docker container for postgres 18.1
- It needs to copy a script file called docker_pg_dump.sh to the container
- This script will run a pg_dump and generate a .tar.gz.br file
- This file is transferred from container back to ec2 instance
- This file needs to be uploaded to AWS S3
- Email is sent and then the file is deleted from ec2
- Script above works if everything works well
- If any of the steps go wrong like container already exists or there was trouble connecting, it leaves docker containers dangling and I am not getting any emails with the actual error message inside
- how do I achieve getting the actual error message and the step that blew up inside email while shutting the containers down if something goes wrong

```
#!/usr/bin/env bash

# This script runs on AWS EC2
# It's job is to orchestrate perform a pg_dump inside a docker container corresponding to PostgreSQL version used by AWS RDS database
# The package manager on EC2 might not have the same version of PostgreSQL as AWS RDS available as an installable package
# The pg_dump command will only work if the pg_dump executable used is the same version as the database major version used by AWS RDS
# The pg_dump executable from the docker container is used to perform a dump of the AWS RDS database

# Run a container for PostgreSQL with the same version as the one used by AWS RDS
# Install brotli and tar inside this container
# Copy .pgpass file from AWS EC2 to the container
# Copy or download the AWS RDS certificate needed by PostgreSQL server
# Run the docker_dump.sh script with arguments required if any
# Copy the generated dump file back to AWS EC2 from the container
# Stop and remove the container

# We only require the error message in order send an email
# We need data from the stderr stream but want nothing from the stdout stream
# For error message capture, refer to this answer https://unix.stackexchange.com/a/499443/290371

script_directory=$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" &>/dev/null && pwd)
cd "${script_directory}" || exit 1

# shellcheck source=/dev/null
source "${script_directory}/.env"

function log_info() {
local -r message="$1"
printf "INFO: %s\n" "${message}"
}

function log_error() {
local -r message="$1"
printf "ERROR: %s\n" "${message}"
}

function cleanup() {
local exit_code="$1"
log_info "cleanup function was called ${exit_code}"
}

function copy_files_from_container() {
if [[ -z "$(command -v docker)" ]]; then
log_error "The docker command was not found, check if it is installed"
return 1
fi

if [[ "$#" -lt 2 ]]; then
log_error "Usage: copy_files_from_container <from_path> <to_path>"
return 1
fi

local -r from_path="$1"
local -r to_path="$2"
shift 2

if [[ -z "${from_path}" ]]; then
log_error "No value was supplied for from_path:${from_path}"
return 1
fi

if [[ -z "${to_path}" ]]; then
log_error "No value was supplied for to_path:${to_path}"
return 1
fi

if ! docker cp \
"${from_path}" \
"${to_path}"; then
return 1
fi
}

function copy_files_to_container() {
if [[ -z "$(command -v docker)" ]]; then
log_error "The docker command was not found, check if it is installed"
return 1
fi

if [[ "$#" -lt 2 ]]; then
log_error "Usage: copy_files_to_container <from_path> <to_path>"
return 1
fi

local -r from_path="$1"
local -r to_path="$2"
shift 2

if [[ -z "${from_path}" ]]; then
log_error "No value was supplied for from_path:${from_path}"
return 1
fi

if [[ -z "${to_path}" ]]; then
log_error "No value was supplied for to_path:${to_path}"
return 1
fi

if ! docker cp \
"${from_path}" \
"${to_path}"; then
return 1
fi
}

function fetch_table_row_counts() {
if [[ -z