I wrote pmtud.sh this weekend to get the MTU of a link (or tunnel) quickly, reliably, and without sending a ton of pings. It can do so in about 11 pings per target.

I had fun writing the entire thing in sh, tried making it "POSIX-compliant," but probably failed somewhere since POSIX isn't worded well. The script only needs dig and ping and uses shell built-ins for everything else. It performs a recursive binary search on the MTU search domain and asynchronously queues pings for later.

why I can't pass my input in foo function

 undefined

    
foo() {
    read -r -p "delete $name (default is no) [y/n]?  " choice
    choice="${choice:-n}"
    echo "\$choice: $choice"
}

printf "%s\n" "foo" "bar" "baz" "eggs" "spam" | while read -r name; do
    foo


  

Expected result:

 undefined

    
delete foo (default is no) [y/n]? USER_INPUT
$choice: USER_INPUT
delete bar (default is no) [y/n]? USER_INPUT
$choice: USER_INPUT
# truncated

  

Actual output:

 undefined

    
$choice: bar
$choice: eggs
$choice: n

  

[!NOTE] Actual output produced without user interaction

This article describes bind and shows the ways you can use it to make binding to write faster and more comfortably use bash.

In the code below we wait for a background process three times. In the first paragraph we get the expected 0 return code from the wait. In the second paragraph the only change is wrapping the wait in a command substitution which instead gives a 255 return code. In the third paragraph the only change is wrapping the wait in a subshell which gives a 127 return code. Why is this?

 bash

    
sleep 1 &
wait $!
echo $?                     # prints "0"

sleep 1 &
a=$(wait $!)                # <---- only difference is cmd substitution
echo $?                      # prints "255"

sleep 1 &
(wait $! &>/dev/null)       # <---- only difference is subshell
echo $?                     # prints "127"

  

Thanks in advance for your thoughts!

EDIT: updated to include the subshell final example also, which gives a clue

I'm studying bash, and I came across this Stackoverflow thread which contains this bit of code:

 undefined

    
var="abcde"
echo ${var%d*}


  

The output is abc, but I can't figure out why. I understand that %d is used to indicate an integer number and * represents anything, but I can't figure out why those together would truncate var to only 3 characters.

I made grebuntu to merge all of the separate scripts into one script for all distros, but it doesn't work. The individual scripts do, I tested in VMs. What could have caused the issue? the script in question is tsubuntu.sh btw, can be found in the repo The original scripts are available at https://github.com/Tsu-gu/tsubuntu

Hi all,

I'm trying to put a command together to download a bz2 archive containing an img file and decompress it immediately, basically without saving it to the filesystem. Can this be done?

This is what I've come up with so far, but it's incomplete: wget -qO- "https://opnsense.com/.../img.bz2" | bzip2 -dv

Background: Trying to install OPNsense on Linode. Their hacky official guide says the best way to install FreeBSD is via the rescue mode. But FreeBSD posts their images as .img, so the filesystem size limitation of 1GB for the rescue image isn't an issue. But with OPNsense I need to decompress it.

I have a few different options on how to install this but I see it as a good reason to learn more about stdin/out, piping commands, etc.

Thanks in advance.

Edit

After a long process of roaming the web, re-runs and troubleshoot the script with this wonderful community, the script is functional and does what it's intended to do. The script itself is probably even further improvable in terms of efficiency/logic, but I lack the necessary skills/knowledge to do so, feel free to copy, edit or even propose a more efficient way of doing the same thing.

I'm greatly thankful to @AernaLingus@hexbear.net, @GenderNeutralBro@lemmy.sdf.org, @hydroptic@sopuli.xyz and Phil Harvey (exiftool) for their help, time and all the great idea's (and spoon-feeding me with simple and comprehensive examples ! )

How to use

Prerequisites:

• parallel package installed on your distribution

Copy/past the below script in a file and make it executable. Change the start_range/end_range to your needs and install the parallel package depending

I was able to setup a debugger using a launch mode using Visual Studio Code with the Bash Debug extension. Is it possible to setup the debugger in VSCode to be able to debug a bash script using a attach debug mode?

For debugging scripts on the host machine and scripts inside a docker container?

A choice selector in pure bash (and compatible with zsh), inspired by fzf which I'm working on

cross-posted from: https://lemm.ee/post/23155648

Here is the script.

 undefined

    

#!/usr/bin/env bash
# Download and search youtube subs
# deps yt-dlp ,awk, perl, any one or more of either ugrep, ripgrep, grep
# usage "script youtube_url"


main() {
    url="$@"
    check_if_url
    get_video_id
    search_for_downloaded_matching_files
    set_download_boolean_flag
    download_subs
    read_and_format_transcript_file
    echo_description_file
    user_search
}


# Iterate over the array and add items to the new array if they match the regex
check_if_url() {
    local regex='^https://[^[:space:]]+$'
        if ! [[ $url =~ $regex ]]; then
            echo "Invalid input. Valid input is a url matching regex ${regex}"
            exit 1
        fi
}


get_video_id() {
    video_id=$(echo "$url" | sed -n 's/.*v=\([^&]*\).*/\1/p')
}


search_for_downloaded_matching_files() {
    # Find newest created files matching the
  

I made a script that downloads from youtube super fast using a custom aria2 build.

Aria2 https://github.com/P3TERX/Aria2-Pro-Core/releases

ffmpeg build https://github.com/yt-dlp/FFmpeg-Builds/releases

I choose ffmpeg-master-latest-linux64-gpl.tar.xz

 undefined

    
#!/usr/bin/env bash
#set -x

if [[ -z $@ ]]; then
    echo "specify download url"
    exit
fi

dir_dl="$PWD"
url="$@"

ffmpeg_dir="$HOME/.local/bin.notpath/"
download_archive_dir="$HOME/Videos/yt-dlp/"
download_archive_filename=".yt-dlp-archived-done.txt"

mkdir -p "$download_archive_dir"

youtube_match_regex='^.*(youtube[.]com|youtu[.]be|youtube-nocookie[.]com).*$'

if [[ "$1" =~ $youtube_match_regex ]]; then
    url="$(echo "$@" | perl -pe 's/((?:http:|https:)*?\/\/(?:www\.|)(?:youtube\.com|m\.youtube\.com|youtu\.|#youtube-nocookie\.com).*(?:c(?:hannel)?\/|u(?:ser)?\/|v=|v%3D|v\/|(?:a|p)\/(?:a|u)\/\d.*\/|watch\?|vi(?:=|\/)|\/#embed\/|oembed\?|be\/|e\/)([^&?%#\/\n]+)).*/$1/gm')"
    yt-dlp \
    --check-formats \
    --clean-
  

[SOLVED] Solution: https://lemmy.ml/comment/4317564

I am doing all of this using ChatGPT, I know enough bash to understand the script partially, but not enough to write the script myself.

I recently posted bash script(click) to download songs on spotify using Spotdl Updated Post

This is all good, but I am not trying to download whole playlists and I want to make sure to

1. Not download any songs multiple times by comparing the files you are trying to download with the songs you have downloaded already.
2. Add the songs' URL to the Archieve_file so it doesn't download it again. i.e., compare and if present, exit loop, if not present in file, download and add link to the file.

This was easier when I was dealing with only song links and not playlist links. But now, playlists complicates the equation, but if I can achieve this, I can basically add this script to `c

I would rather prefer that you would buy spotify premium if you can. But, till you can, there's always spotdl which can allow you to download your songs

Installation of spotdl (github page click here): https://i.imgur.com/5g6uUgD.png

https://paste.debian.net/plain/1293528 a very simple script, you don't actually need the script, but it makes it easier to download songs.

btw, I am using file manager nemo here, if you want something else, change it to your default file manager, if you don't want to open folder, well remove last but one line.

execute this command first and when nano text edit appears, paste the debian pastebin in there. ::: spoiler spoiler

:::

This will remove all sponsors, download subtitles and view it when you are watching a video. Modify and Share this all over if you like! Edit: Give credits to this community or Lemmy in general if you are posting this or a modified form (please do share) of this elsewhere. Some popularity would do Lemmy good.

Few requirements:

1. You should be using Linux to run it.
2. Create a folder named yt-dlp in Videos folder or else change the location in the script below.
3. You should have yt-dlp not youtube-dl on your system. You can do this by sudo apt install yt-dlp or use your distro's package installer.
4. Save this file with any name in your home folder (or whichever folder you are you most comfortable with and give it execution permissions by chmod +x name

Debian Pastebin Thanks to folds at debian for making a tor network friendly pastebin. I have noticed that sometimes scripts get corrupted here, so best copy this from pastebi

The issue is that if my script is correctly done, a SVG is supposed to be exported to PNG with a fixed width, the script seems to work fine, but when I check it out again on Inkscape*, it shows me the original SVG size, not the resized PNG exported picture.

Here's a folder with the script and a random SVG I'm using for testing.

*To check the size of the picture in Inkscape, we need to change the units in the top bar, and then see the numbers that shows. The screenshot shows a 14,79 cm x 9,85 cm, instead of 10,5 cm x 6,9 cm.

I want to have a selector in a "case" menu, so I show the options:

 undefined

           1) option A
       2) option B
       3) option C


  

Then read the choice (let's say it's B), remove the previous menu and show this instead:

 undefined

           1) option A
     » 2) option B
       3) option C


  

How can I do this? I know we can remove the current line with echo -ne "\r", but I have no idea of how to do it with several