What happens if I do kill -TERM 0

I know sending TERM to 0 will send TERM to ALL the process in current process group but will the following cause infinite loop?

trap "kill -TERM 0" TERM

./ child_process


I am trying to figure out the behaviour of current process after sending kill -TERM 0

https://redd.it/13bphhw
@r_bash

Is it true that bash/sh (or shell languages in general) were first designed to be used by end users and not programmers?

I don't know where I heard or read this first but I can't find any good source on it, is it true that shell languages were first designed to be used by Unix end users in the 70s-90s who didn't know much about programming?

https://redd.it/13bxtlp
@r_bash

How to close all previously running gnome terminals, and start up new ones? pkill doestn work.

Hi, i would really appreciate some help with a simple noscript. I have an autonomous robot running on ROS (robot operating system).


My task right now is this:
1. I have 6-7 terminals running at all times. At a certain point of an automated process (robot coming to dock), I want to close all running terminals
2. Run specific commands to launch robot processes

I have tried using pkill to close all terminals but when I try to run commands after that, it doesnt work. Could you point me in the right direction?

​

Thanks

https://redd.it/13bwqwb
@r_bash

Help with referencing a variable and dealing with quotes, escapes, and braces?

These are the source folders in an rsync command. It works as-is but I can't figure out how to put this in a variable and then refer to the variable instead. All on one line, it's:

>/Users/$USER/Library/./Mobile\\ Documents/com\~apple\~{Pages,Numbers,Keynote}/ /Users/$USER/./Documents/Folder\\ name

I tried putting it in a variable as

>SOURCE= "/Users/$USER/Library/./Mobile Documents/com\~apple\~{Pages,Numbers,Keynote}/ /Users/$USER/./Documents/Developer/Folder name"

And then referring to

>"${SOURCE}"

I also tried the variable reference without curly braces and without quotes, and adding an escape before the spaces in the variable. Nothing I've tried works. I get an error message that the folder can't be found. The error quotes both folder references together. I think my issue is properly handling spaces when inside a quote that defines a variable, and maybe the braces when in a variable.

My underlying goal is to have a variable that includes all the source folders, and then just refer to the variable in the rsync command.

https://redd.it/13c2br3
@r_bash

Amazing ssh banner for full node

https://github.com/st3b1t/Satoshi.motd

https://preview.redd.it/dzy6w8l3epya1.png?width=763&format=png&auto=webp&v=enabled&s=cd0cd3dc25fe4b15d9727c897255fd8ab426bc70

https://redd.it/13cagbp
@r_bash

Fish-like dirhistory (prevd/nextd) for Bash

Hello Bash users,

I while ago I came across this video extolling the virtue of Fish's Alt-Left and Alt-Right key-bindings.

Those binding provide a cd - experience on steroids, instead of being limited to just one level (back and forward between the current and last directory), Alt-Left (prevd) and Alt-Right (nextd) instead navigate the full directory stack of the current session.

Zsh via Oh My Zsh provides the Dirhistory plugin to mimic that functionality.

But what about Bash?

I could not find a solution, maybe someone has implemented it, but I could not find it, so I implemented my own solution which is this:

cd() {
local target="$@"
if [ -z "$target" ]; then
# Handle 'cd' without arguments; change to the $HOME directory.
target="$HOME"
fi

# Note, if the target directory is the same as the current directory
# do nothing since we don't want to needlessly populate the directory stack
# with repeat entries.
if [ "$target" != "$PWD" ]; then
\builtin pushd "$target" 1>/dev/null
fi
}

# Alt-Left: rotate back in the directory stack.
bind -x '"\C-x\C-p": "pushd +1 &>/dev/null"'
bind '"\e1;3D":"\C-x\C-p\n"'
# Alt-Right rotate forward in the directory stack.
bind -x '"\C-x\C-n": "pushd -0 &>/dev/null"'
bind '"\e[1;3C":"\C-x\C-n\n"'

We override `cd` to pushd and we then use `pushd` to rotate the directory rather than use `popd` which will eliminate item from the stack. We don't want to eliminate items since we may wish to go forward again, we want rotation.

The binding looks a bit ugly I agree, according to [this StackExchange thread it is the way to silently execute a binding; aka do not print out pushd +1 &>/dev/null in the command line. I use Control-p and Control-n intermediaries since I don't use those bindings in the command line. If there is a nicer way to do this, please pass it on.

But overall, not a lot of code to obtain Fish-like directory stack navigation.

If there are any issues let me know, otherwise enjoy.

https://redd.it/13cfbbp
@r_bash

Is there a difference in execution between executing a command and using an alias for the exact same command ?

I want to use a command semi often, so I put an alias for this command in my .bashrc but when I execute it, it throws an error that doesn't happen when I execute the command it is aliased directly.

I want to execute yt-dlp with a specific url in different directories, so I save the url in a "url.txt" file and execute the command

yt-dlp $(cat url.txt)

which works perfectly, but when I use the alias to the same command it can't read the url, is it the use of a subshell that isn't available in an alias ? would it be possible in a function ?

​

Also, unrelated, but to get the second to last line of a file, is there a better way than using

tail -n 2 foo | head -n 1

?

https://redd.it/13cwrib
@r_bash

Kube-dialog update

Hi, kube-dialog got an update! Edit cmd added to cronjobs. And filtering updated, you can filter by status info using a template like this '#...'! Extremely handy!


https://preview.redd.it/b839g6fuquya1.png?width=883&format=png&auto=webp&v=enabled&s=3074e400a90f1fc32c4f2c4091e2781f9f5944fd

https://redd.it/13d2dhw
@r_bash

Can anyone explain in English what these lines do?

I'm completely new to bash or Linux in general but have been using other languages many years ago so know the basics of strings etc.
I'm failing to understand these lines other than they are extracting something from one file and creating some variables. I can't find anything on -t or -p and I think "${1} might be an argument passed into this noscript. Other than that, I'm stumped.

`5 PREDICTION_START=\`/usr/bin/predict -t /home/bob/weather/predict/weather.tle -p "${1}" | head -1\``
`6 PREDICTION_END=\`/usr/bin/predict -t /home/bob/weather/predict/weather.tle -p "${1}" | tail -1\``
`7 MAXELEV=\`/usr/bin/predict -t /home/bob/weather/predict/weather.tle -p "${1}" | awk -v max=0 '{if($5>max){max=$5}}END{print max}'\``

https://redd.it/13eo6zr
@r_bash

Bash noscript to send email from your terminal
https://owlhowto.com/bash-noscript-to-send-email-from-your-terminal/

https://redd.it/13erkg7
@r_bash

Text string is not working for me.

Mint+MATE-21.1: Hi, fairly new to Bash, but not programming as such. I want to insert a string into anther string so I only need to change the variable for a list of strings within a bunch of similar noscripts. e.g.

aname = "willow"
"cp -a /home/"$aname"/bakall/ /home/open/backups/all
"cp -a /home/"$aname"/baknew/ /home/open/backups/new
"cp -a /home/"$aname"/baklast/ /home/open/backups/last

As a test, I first created a basic noscript and set it as executable

#!/bin/bash
aname="willow"
echo $aname

When I run that, nothing shows up other than the CLI prompt again, so I tried

echo ${aname}

same again, just the CLI prompt, no errors -- nothing.


If I type those directly into the CL in 2-lines it works as expected and shows "willow"

What am I doing wrong in the noscript?

https://redd.it/13eur30
@r_bash

I wrote a classic snake implementation in pure BASH v5.1+
https://github.com/wick3dr0se/snake

https://redd.it/13f0ipg
@r_bash

My first bash noscript, probably a disaster but apparently usable

https://github.com/Vdevelasco/quickCommand

I want to know what you guys think about this. Probably the style is going to be a mess, it works, but it's a mess. Any suggestions are welcome :)

https://redd.it/13f8gma
@r_bash

Inline man page as help.

A little noscript of mine showcasing inline man page for help. If call with -h sed is used to extract the man page and display it with man -l

I hope someone finds it helpful.

#!/bin/bash
#> .TH PDF2OCR-5
#> .SH NAME
#> pdf2ocr \- convert PDF to PNG, OCR and extract text.
#> .SH SYNOPSIS
#> .B pdf2ocr
#> \fB\-h\fR
#> \fB\-l\fR \fIlang\fP
#> .IR files ...
#> .SH DESCRIPTION
#> .B pdf2ocr
#> This is a Bash noscript that converts PDF files to PNG, applies OCR using
#> \fITesseract\fP with a German language option, and extracts text to a text
#> file. It takes options -h for help and -l for the language code. It uses the
#> 'convert' command to convert PDFs to PNGs and then loops through each PNG
#> file to apply OCR and extract the text using the Tesseract command. Finally,
#> the noscript deletes the PNG files. It has a manpage for more information and
#> references the Tesseract documentation.
#> .SS OPTIONS

# Default to German for OCR
lang=deu

# Get Options
while getopts ":hl:" options
do case "${options}" in
#> .TP
#> .BR \-h
#> Get help in form of a manpage
#>
h)
sed -n 's/^#>\s//p' $0 | man -l -
exit 1;;
#> .TP
#> .BR \-l
#> The language code use by \fITesseract\fP to do character recognition.
#> defaults to "deu" for German.
l)
lang=${OPTARG}
shift;;
esac
shift
done

# Show short help, if no file is given.
if [ -z "$" ]
then
cat << EOF
Syntax: %s: -h -l lang Dateien\n
EOF
exit 0
fi

# Do the actual work:
for f in "$"
do
base=$(basename $(tr ' ' '_' <<< $f) .pdf)
convert -density 300x300 $f -colorspace RGB -density 300x300 $base.png
for png in $basepng
do
tesseract $png - --dpi 300 -l ${lang} >> $base.txt
rm $png
done
done

#> .SH "SEE ALSO"
#> tesseract(5)

https://redd.it/13fhkgb
@r_bash

How to deal with valid constructions when set -e is in effect ?

Hi there !

I learned that is a good practice to use `set -eu` on my noscripts. Fine.

But how I should handle sittuations wher I expect a command return a non zero status and it is ok ?

For instance, smartctl may return a non zero status when there is some problem or when I want to test the return status of `grep -q`

echo $var | grep -q is_this_string_present;
if [[ "$?" == "0" //; ] then...

in both situations the noscript will exit silent, which is not desirable...in the code above, the `if` statement never gets executed.....you see ?

Talking about that, how to prevent the noscript exit silent when an legitm error occur ? (with `set -e`)

https://redd.it/13fk6uc
@r_bash

A Robust Bash Script for Partial Cloning of Git Repositories

Hello fellow Redditors,

I wanted to share a bash noscript I've been working on that makes it easy to perform a partial clone of a Git repository. This noscript is especially useful if you only want to clone a specific branch and directory, rather than the entire repository.

Here's how it works:

1. The noscript prompts you to input the Git repository URL. It validates the URL to ensure it's correct.
2. Next, it asks for the depth of the clone. This is a number that specifies how many recent commits you want to include in your clone. By default, the depth is 1, meaning only the most recent commit is included.
3. You're then asked to input the branch you want to checkout. The default branch is 'main'.
4. The noscript then performs a sparse clone of the repository. This type of clone doesn't download the entire repository content but only the history of specific files or directories, making the clone operation faster and the resulting local repository smaller.
5. After the clone is successful, the noscript enables sparse checkout, which allows you to limit which files and folders are checked out to your local working copy.
6. Finally, you're prompted to input the specific directory you want to checkout. By default, this is the root directory.

I hope you find this noscript useful! Feel free to modify it according to your needs and share your improvements. Looking forward to your feedback!

https://github.com/BalliAsghar/partial-clone

Happy coding!

https://redd.it/13flrua
@r_bash

Bash must not run in POSIX mode. Please unset POSIXLYCORRECT and try again.

I'm trying to run a ruby noscript that downloads the Homebrew [install.sh](https://install.sh) noscript and executes it, but I'm getting **Bash must not run in POSIX mode. Please unset POSIXLY\CORRECT and try again.

Did some little research on it, but still not clear what it is.

Can you give a little explanation on what it is, is it safe to unset it? and... What kind of "unexpected or different behavior" may I experience if unset?

https://redd.it/13fmc3l
@r_bash

piu-piu

Massive piu-piu update!
Finally got some time to fix some bugs and merge starship branch into master. For those who unfamiliar with piu-piu it's a scroller game with text based graphics written on bash that runs in CLI terminals. It looks like this:

shoot them all

Enemies can drop some power-ups like health packs, you'll need them to stay alive a bit longer:

health pack

Ammo is depleting, grab some in the process to keep firing:

ammo pack

And gun upgrades x2, x3, x4 and x5:

gun x2

gun x3

gun x4

gun x5

Here is gun x5 in action)

x5 in action

But the small ones it's just the beginning, there is a big guy in the end, Boss)

boss fight

The game supports multiplayer modes co-op and duel. It uses netcat for this so it must be installed if you want to play with friend.

team play

duel

Spoiler, I'm planing to do the next chapter on Mars, here is the story:

here the story goes

See you on Mars!)

https://i.redd.it/utlgcdbxmgza1.gif

https://redd.it/13fw8ph
@r_bash

AppImagen: A noscript that generates a custom AppImage from Debian or from a PPA of your choice for the previous (not the oldest) and still supported Ubuntu LTS

https://redd.it/13gljdc
@r_bash

Made a simple bash noscript to stream from Lofi Girl or fccCodeRadio
https://redd.it/13gk9d9
@r_bash

Proxmox check assigned PCIe device noscript isn't working.

I'm trying to check for unassigned and assigned SR-IOV Virtual Function PCIe devices in Proxmox, but the bash noscript isn't displaying the PCIe devices attached to the VMs, and is instead stating "No PCIe device assigned". Any thoughts?

&#x200B;

Basic idea:

* Get a list of the VM IDs, and other info with `qm list --full`
* Get a list of all PCIe devices, except the main controllers with `lspci | grep "Ethernet controller: | grep -v "Ethernet controller: Intel Corporation Ethernet Controller 10G X550T (rev 01)"`
* Find the PCIe devices attached to each VM by getting all VMIDs with the from the qm list --full command, then running `qm config <VMID> | grep -E 'hostpci'` to get the attached PCIe device ID.
* Output a list of the VMs, assigned PCIe devices to each VM, and then all of the unassigned PCIe devices.

&#x200B;

#!/bin/bash

# Get the list of VMs and their details
vm_list=$(qm list --full)

# Get a list of all Ethernet devices excluding specified ones
all_eth_devices=$(lspci | grep "Ethernet controller" | grep -v "Ethernet controller: Intel Corporation Ethernet Controller 10G X550T (rev 01)" | awk '{print $1}')

# Initialize an empty array to store assigned PCIe devices
assigned_pcie_devices=()

# Iterate through the VM list
while read -r line; do
# Skip the header line
if [[ "$line" =~ VMID ]]; then
continue
fi

# Get VMID, NAME, and STATUS
vmid=$(echo "$line" | awk '{print $1}')
name=$(echo "$line" | awk '{print $2}')
status=$(echo "$line" | awk '{print $3}')

# Get hostpci configuration
hostpci=$(qm config "$vmid" 2>/dev/null | grep -E 'hostpci\d+')

# Check if the hostpci configuration exists
if [ ! -z "$hostpci" ]; then
# Extract all PCIe devices
pcie_devices=$(echo "$hostpci" | perl -ne 'print "$1\n" while(/(?:^|\s)host=([^,]+)/g)')

# Concatenate the PCIe devices into a single string
pcie_device_str=$(echo "$pcie_devices" | tr '\n' ',' | sed 's/,$//')

# Add PCIe devices to the assigned devices array
assigned_pcie_devices+=($pcie_devices)

# Print VMID, NAME, STATUS, and PCIe devices
echo "VMID: $vmid, NAME: $name, STATUS: $status, PCIe Devices: $pcie_device_str"
else
# Print VMID, NAME, and STATUS with "No PCIe device assigned"
echo "VMID: $vmid, NAME: $name, STATUS: $status, No PCIe device assigned."
fi
done <<< "$(echo "$vm_list" | tail -n +3)"

# Print a list of unassigned PCIe devices
echo "Unassigned PCIe devices:"
for device in $all_eth_devices; do
if ! [[ "${assigned_pcie_devices[*]}" =~ $device ]]; then
echo "$device"
fi
done

Any help would be greatly apprciated!

https://redd.it/13gu78h
@r_bash