r_bash – Telegram
How do I do this with bash?

I have multiple videos and images in one folder. The goal is to use ffmpeg to add thumbnails to the videos.

the command to attach a thumbnail to a single video is

ffmpeg -i input.mkv -attach image.jpg -metadata:s:t:0 mimetype=image/jpeg -c copy output.mkv

The videos named as such

00001 - vidname.mkv

00002- vidname.mkv

00100 - vidname.mkv

01000 - vidname.mkv

and etc

as you can see, I have added number prefixes with a padding of zeros to the video names. The corresponding images are named in a similar manner .

00001.jpg

00002.jpg

00100.jpg

I want to attach the images to the videos based on the prefixes.

00001.jpg is to be attached to 00001 - vidname.mkv, and so on

https://redd.it/1npapqb
@r_bash
Few functions and aliased I use on my ~/.bashrc

Sometimes it's good to post something you wanted to read in a specific /r, so I'm doing it.
Down below there are a couple of functions and aliases that I have on my \~/.bashrc that I find extremely useful and handy. Let me know if those can be improved somehow.
Hope it'll help at least one person!

cd(){
if [[ $1 =~ ^-[0-9]+$ ]]; then
local n=${1#-}
local path=""
for(( i=0;i<n;i++ )); do
path+="../"
done
builtin cd "$path"
else
builtin cd "$@"
fi
}

rename(){
local n="$*"
PROMPT_COMMAND="echo -en '\033]0;${n}\007'"
}

export PATH="$HOME/.local/bin:$PATH"
alias execute="chmod +x"
alias editsh="vim ~/.bashrc"
alias sourcesh="source ~/.bashrc"
alias uu="sudo apt update && sudo apt upgrade -y"
alias desk="cd ~/Desktop"
alias down="cd ~/Downloads"
alias udb="sudo updatedb"
alias release="lsb_release -a"

https://redd.it/1nq77o6
@r_bash
What are ways to setup an isolated environment for testing shell noscripts?

I want to check that my shell noscripts won't fail if some non-standard commands are missing (e.g. qemu-system-*). To solve this problem with the least overhead only tools like schroot, docker or lxd come to mind. I think that potentially I could change in some way environment variables like PATH to emulate missing commands. However, I also want to prevent harming my FS while testing noscripts (protect myself from accidental sudo rm -rf --no-preserve-root /).

What are your thoughts?

https://redd.it/1nqhwpb
@r_bash
LLaMA en macOS

* Estoy trabajando en un conjunto de noscripts Bash para manejar modelos LLaMA en macOS. Aquí va un ejemplo de cómo valido dependencias con bash. ¿Alguien más ha intentado algo parecido?
* $MAIN\_BINARY" \\
* \-m "$MODELO\_PATH" \\
* \--ctx-size 31000 \\
* \--n-predict 500 \\
* \--color \\
* \--temp 1.2 \\
* \--threads 6 \\
* \--prompt "$(cat "$PROMPT\_SISTEMA") $(cat "$PROMPT\_FILE")" 2>&1 | grep -v 'llama\_' | tee >(tee -a "$LOG\_PATH") >> "$TEMP\_OUT"

https://redd.it/1nqxdhm
@r_bash
xargs for functions

I love the power of `xargs`. But it doesn't work with Bash functions. Here is `fargs`, which works with functions.

# Usage: source ~/bin/lib.sh
# This is a libary to be sourced by noscripts, such as ~/.bashrc:

# fargs - xargs for functions
# No space in xargs options. Bad: -n 2. Good: -n2 or --max-args=2
# All bash functions and local env vars will be accessible.
# otherwise, works just like xargs.
fargs() {
# Find the index of the first non-option argument, which should be the command
local cmd_start_index=1
for arg in "$@"; do
if [[ "$arg" != -* ]]; then
break
fi
((cmd_start_index++))
done

# Extract xargs options and the command
local opts=("${@:1:$((cmd_start_index - 1))}")
local cmd=("${@:$cmd_start_index}")
if [[ ${#cmd[@]} -eq 0 ]]; then cmd=("echo"); fi

# xargs builds command strings by passing stdin items as arguments to `echo`.
# The resulting strings (e.g., "my_func arg1") are then executed by `eval`.
# This allows xargs to call shell functions, which are not exported to subshells.
eval "$(xargs "${opts[@]}" bash -c 'printf "%q " "$@"; echo' -- "${cmd[@]}")"
}

https://redd.it/1nqij6u
@r_bash
Expect driving me crazy! Timeout or Loop or Nada

I try to read the firmware version of a device from a spawned ssh connection. So far so good. I have a block that basically puts "We are in" just as a debug print to see, wether the login works. Next block:

# Detecting firmware version
set deviceInfoRequested "no"
send "\r"
expect {
-re "#" {
if {"\$deviceInfoRequested" eq "no"} {
set deviceInfoRequested "yes"
send "show device\r"
after 500
expcontinue
}
}
-re {Firmware Version: ([0-9]+)\.([0-9]+)} {
set major \$expect
out(1,string)
set minor \$expectout(2,string)
puts "Detected Firmware version: \$major.\$minor"

# Compare numerically
if { (\$major > 4) || (\$major == 4 && \$minor > 2) } {
puts ">>> using newer Syntax for gateway"
set raritanVersion "new"
} else {
set raritanVersion "classic"
puts ">>> using old Syntax for gateway"
}
flush stdout
}
timeout {
puts "Timeout waiting for firmware version"
set raritanVersion "unknown"
exit 1
}
} # Detecting firmware version
set deviceInfoRequested "no"
send "\r"
expect {
-re "#" {
if {"\$deviceInfoRequested" eq "no"} {
set deviceInfoRequested "yes"
send "show device\r"
after 500
exp
continue
}
}
-re {Firmware Version: (0-9+)\.(0-9+)} {
set major \$expectout(1,string)
set minor \$expect
out(2,string)
puts "Detected Firmware version: \$major.\$minor"

# Compare numerically
if { (\$major > 4) || (\$major == 4 && \$minor > 2) } {
puts ">>> using newer Syntax for gateway"
set raritanVersion "new"
} else {
set raritanVersion "classic"
puts ">>> using old Syntax for gateway"
}
flush stdout
}
timeout {
puts "Timeout waiting for firmware version"
set raritanVersion "unknown"
exit 1
}
}

Without the if deviceInfoRequested it loops forever as each new prompt starts with # logically. If I put the # at the end after the Firmware Version detection block (which has no line exp_continue), it first sends show device, than successfully prints "Detected Firmware version: 4.4" and than waits for 5 seconds before the noscript exits... Why, if exp_continue is not used, does it not escape the expect {} block? Of course there are further blocks that follow... But it just times out. I tried send "show device\r" before the expect block, but than it just does not detect it. Also strange: My first expect block waits for either "Welcome" or "#" to detect: Yes I am logged in. This is where it puts "We are in". If I write something like:

first expect block > Prints "We are in" directly (before printing the rest that SSH still receives)
puts "HI"
after 5000
next expect block

The ovserved behavior is not what you might expect: After "We are in" NOTHING is printed for 5 seconds straight. Only than the rest of the login prompt is even printed an donly than we see the HI. Is it just me or is expect a horrible mess? How Shall I implement the logic to detect the firmware here? Direct SSH commands I would prefer, but the device does not support it. I need to rely on expect. I have written a screen handler that does the same that expect does... But it is sooo complicated and hard to debug that I wanted to try something simpler and yet lightweight.

By the way: The "flush stdout" was just a test to see if it makes a difference in behavior/order. Nada. Not at all.

Please tell me you understand what is going on here and why it either just times out, or loops forever or sleeps before printing to stdout although I defined it the other way around. I am not sure what is going on
From naïve to robust: evolving a cron noscript step by step

A “simple” cron noscript can bite you.

I took the classic example running a nightly DB procedure and showed how a naïve one-liner grows into a robust noscript: logging with exec, cleanup with trap, set -euo pipefail, lockfiles, and alerts.

If you’ve ever wondered why your noscript behaves differently under cron, or just want to see the step-by-step hardening, here’s the write-up.

https://medium.com/@subodh.shetty87/the-developers-guide-to-robust-cron-job-noscripts-5286ae1824a5?sk=c99a48abe659a9ea0ce1443b54a5e79a

Feedbacks are welcome. Is there anything I am missing that could make it more robust ??

https://redd.it/1ns4uba
@r_bash
Why use chmod?

Is there a reason to use chmod +x noscript; ./noscript instead of simply running bash noscript?

https://redd.it/1nsn976
@r_bash
Can I get some reviews or opinions on this noscript that I made?

So, I recently made a noscript for me to blink the scroll key like a heartbeat whenever I received a notification from example: Whatsapp or Discord, could I get some honest opinions about it? I decided there would be no better place to share this than good ol' Reddit. Here's the link to the Github repo:

https://github.com/Squary5928/notifled

(Btw, I'm kind of in a haste because I have to install Windows XP and fix a plugin on my minecraft server, hence the short denoscription)

https://redd.it/1nsprj5
@r_bash
Wrote a utility that makes working with symlinks a little easier.

I know there are many out there that does this. Here is my version. Any feedback on improvements feature/code wise would be helpful.


Thanks.

https://github.com/ctrl-alt-adrian/symlinkit


https://redd.it/1nt1qd6
@r_bash
Black magic quoting issue

Usually I can muddle through these on my own, but this one has really got me stumped. How can I get a window noscript into mpv's command line if it has spaces in it?

I can't find a way to do it where the noscript doesn't just wind up being whatever comes before the first space (no matter how many single quotes or backslashes I use, etc.); the best I've got so far is to replace the spaces with something _isn't_ a space, but _looks like_ one (the "En Quad" character) but I'd rather do it "the right way" (not to mention, to figure out _how_ to do it in case I run into something like this in the future where sed isn't an option).

This is the noscript I've been using to test...Reddit's editor inserted a bunch of backslashes and extra whitespace when I pasted it in, which I tried to revert.

I realize the way I'm building up the command line (at the end, with the $command_line variable) looks silly when it's reduced to its core for testing, but there's _a lot_ more logic in the real noscript and building the command line this way is integral to the overall process, so it's not something I'm willing to change.

```sh
#!/bin/bash

set -x

## En Quad / U+2000 / &#8192
#special_space=$'\u2000' ## En Quad (8-bit clean but requires BASH)
special_space=" " ## En Quad (the literal character)

case ${1} in
underscores)
window_noscript="Underscores:_Title_with_no_spaces."
;;
backslashes)
window_noscript="Backslashes:\ Title\ with\ backslashed\ spaces."
;;
spaces)
window_noscript="Spaces: Title with spaces."
;;
special)
raw_noscript="Special: Title with special spaces."
window_noscript=$(echo "${raw_noscript}" | sed -e "s/ /${special_space}/g")
;;
'')
${0} underscores &
${0} backslashes &
${0} spaces &
${0} special &
exit 0
;;
esac

##
## From here down is the "real" part of the noscript
##

command_line="mpv"
command_line="${command_line} --idle"
command_line="${command_line} --force-window"

## This is what I would have expected to need, but it
## doesn't work either
#command_line="${command_line} --noscript=\"${window_noscript}\""
command_line="${command_line} --noscript=${window_noscript}"

${command_line}

## EOF
########
```

https://redd.it/1nty619
@r_bash
I have a copy of this book, is it worth studying this end to end?
https://redd.it/1nux1tf
@r_bash
bash noscript that can detect all individual keystrokes?

I'm talking all individual keystrokes. Obviously, if you can open a pipe in a raw form, then stroking a glyph key will generate byte of data into the pipe. But what about the arrow keys? In the Linux console/GNOME Terminal, they generate ANSI escape codes, which, again, in raw read mode should be immediately available. But then, there are the modifier keys.

Is there any way that a bash noscript can reopen the terminal such that even stroking Alt, or Ctrl, or Shift individually can be detected?

https://redd.it/1nw4j9j
@r_bash
Space in file (Space in this filename bandit lvl2 .)
https://redd.it/1nwtofq
@r_bash
Read systemd env file

I have a systemd environment file like:

foo=bar


I want to read this into exported Bash variables.

However, the right-hand side can contain special characters like $, ", or ', and these should be used literally (just as systemd reads them).

How to do that?



https://redd.it/1nx63dy
@r_bash
NLP using Bash jq & Nix

Is this too Nix for you guys or agree it's dope?

https://quackhack-mcblindy.github.io/blog/

https://redd.it/1nxlssd
@r_bash
How to learn bash noscripts?

I have been really wanting to learn bash noscripts but I’m just not sure where to start. I already know the basics like variables, if, functions. Also this is an example noscript that I want to learn to be able to make it’s just noscript that fzf searches my tmuxifier layouts a remove the one I pick.

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