How to insert text after a specific line in a file?

Example

​

specific line
text
text 2

I now want to add "text 3" under "specific line" so it looks like this

specific line
text 3
text
text 2

https://redd.it/10k3fg1
@r_bash

Simple, open-source, lightweight stress tool
https://github.com/ddosify/ddosify

https://redd.it/10kdt5g
@r_bash

Recognize any text or characters at the end of a filename before the extension

I am creating an inotify-tools noscript and this currently works for any file that looks something like `2023-01-24_14-59-22.mp4`:

inotifywait --recursive --monitor --quiet -e moved_to -e close_write --format '%w%f' --include [0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]_[0-9][0-9]-[0-9][0-9]-[0-9][0-9].mp4 /watch/folder

Occasionally, an mp4 file might arrive as such: `2023-01-24_14-59-22_edit.mp4` or `2023-01-24_14-59-22_edit_edit.mp4` or other random text or characters at the end of the date/time and before the .mp4 extension. How do I watch for these files as well? I tried `*` or `$` or `\w` and stuff like that and it didn't work, but I'm not entirely understanding the bash documentation. Can someone point me in the right direction?

https://redd.it/10kd8rd
@r_bash

Diff and Grep inside IF statement

Hi Guys

How do I get this command to be either true or false

diff $LAST $CURRENT | grep --exclude-dir=* '^<' >>$EMAILTEXT

Basically if there is no difference between last and current give me a false and if there is a difference give me a true and output the results to email text.
Thanks

https://redd.it/10kitld
@r_bash

Check for string of command output

How can I check for a string from a command output? For example, if I execute:

MP4Box -info $INPUTFILE

And if the file is incomplete, it outputs:

[iso file] Incomplete box mdat - start 40 size 2998060684
[iso file] Incomplete file while reading for dump - aborting parsing
File has no movie (moov) - static data container

I want my noscript to pick up on the word "Incomplete" or something. For example, my bash noscript:

#!/bin/bash

FILENAME=*.mp4
WATCHDIR=/path/to/directory

/usr/bin/inotifywait \
--recursive \
--monitor \
--quiet \
-e movedto \
-e closewrite \
--format '%w%f' \
--includei "$FILENAME" \
"$WATCHDIR" \
| while read -r INPUTFILE; do
echo ""
echo "Transfer stopped. Checking if mp4 file is complete:"
echo ""

if [ $(MP4Box -info $INPUT_FILE) == "Incomplete" ];
then
echo ""
echo "Transfer interrupted."
else
echo ""
echo "Transfer complete."
fi
done

No matter what happens, I cannot get "Transfer interrupted" to echo out even when I interrupt the transfer and the output shows Incomplete file while reading for dump - aborting parsing.

I have tried grep, and every which option I can think of, and it won't work for me. What am I doing wrong?

https://redd.it/10knklt
@r_bash

decrypt a gpg file inside a noscript

would love to get some input on this please. having some issues with getting the noscript to decrypt the gpg file. i am using the file to store passwords i need to to run the noscript. any help would be appreciated. thanks

\#!/bin/bash

\# Decrypt the file using the passphrase
gpg --decrypt-files --batch --yes --passphrase "$(cat passphrase.txt)" encrypted_passwords.gpg -o decrypted_passwords

\# Assign the decrypted passwords to variables
password1="$(cut -d ',' -f1 decrypted_passwords)"
password2="$(cut -d ',' -f2 decrypted_passwords)"


\# first password as an argument
PKR_VAR_vsphere_password= "$password1"


\# second password as an argument
PKR_VAR_winadmin_password="$password2"

https://redd.it/10kunza
@r_bash

Bash aliases best practice

I am a junior/mid data-scientist and developer and it's been years the first thing I do on a new workstation is to add a couple of aliases I cannot live without. But I want to step up a little in terms of best practices. And I have a couple of questions.

The first one: how long can my .bash_aliases file grow? Mine are about 10-20 lines total, but I have so many ideas of adding new stuff. Not sure whether it is a good practice to automate / simplify things to myself or it would just make me forget about the actual syntax of some complex commands.

The second one: do you add custom functions in your .bash_aliases or do they go elsewhere? I have a couple of functions that _really_ are a quick lifehacks such as:

function cds {
cd $1 && ls -lah
}

How would you organize such functions in order to avoid future yourself any headache?

Thanks!

https://redd.it/10kxidg
@r_bash

Boredom PS1 project

I decided I was going to learn a bit more about the PS1 prompt. I started out with a nice easy prompt with \w on one line and the prompt with a custom user token 𝝅 rather than the stock $ on the next.

I liked the setup a lot, so I used the same configuration on my home work station and the termux installation on my phone.

The setup worked great until I started running the wrong commands on the wrong system. For good reason, as the prompts were identical, I decided to see if I could setup my prompt to show a different prompt for an ssh connection.

I had a fun time getting that to actually work. I was making it more complicated than it needed to be, but wait there's more. Now when I connect to my ssh server it shows the IP address of the login before last rather than the current login. With a remote login it is kind of useless to see that you just logged in but it is useful to see if someone logged in before you... Just in case you know.

Once I got that working I decided to take it to a whole new level of ridiculous... Solely because why not. I wanted to see what it would take to show in my local terminal that there was an active connection. Next was to make the command search for an active connection on my SSH port, if one was active it ran one prompt and if no connection, another. it took some trial and error to get that running correctly. Once it was running, I found that it would only update when a new terminal session was opened or if I sourced .bashrc. Which in and of itself wasn't that bad but there had to be a way to get that info without sourcing or starting a new terminal session.

After a bit more trial and error and research on the topic i found the answer to getting that info to update after each command. The PROMPT_COMMAND setting was what did the trick. By wrapping the whole command into a function i was able to call it in the PROMPT_COMMAND which gets evaluated after every command runs.

Now not only will it show an active connection, it will show the last IP to login to that users account. It will also search through a predefined list of known IP addresses and if they match the IP address will be green to denote a known IP and display a custom string so you don't have to look at your own IP addresses. If it returns an unknown IP address it will turn red.

Then to add the finishing touches to this ridiculous project, a red/green light for inactive/active connections respectively, just because I could

I'd like to hear how you all would make it better/different. It was a fun project to learn about the prompt and make sure I used proper escaping. So here is my absolutely, totally, over the top, unnecessary PS1 prompt. Complete with functions and PROMPT_COMMAND

&#x200B;

# This will show if there is an active SSH connection after each command is executed.
# Shows second to last login of current user; best used with AllowUsers in sshdconfig
psONEssh()
{
if [ "$(last | sed -n '2p' | awk '{ print $3 }')" =~ ("XXX.XXX."*|"XXX.XXX.XXX.XXX"|"XXX.XXX.XXX.XXX"|"XXX.XXX.XXX.XXX") ]; then
printf %b "\[\\e1;32m\\KNOWN CONNECTION\n"
else
last | sed -n '2p' | awk '{ print $3 }'
fi
}

psONElocal() # Shows the last login from the current user; best used with AllowUsers in sshdconfig
{
if [ "$(lastlog | grep $(whoami) | awk '{ print $3 }')" =~ ("XXX.XXX."*|"XXX.XXX.XXX.XXX"|"XXX.XXX.XXX.XXX"|"XXX.XXX.XXX.XXX") ]; then
printf %b "\[\\e1;32m\\KNOWN CONNECTION\n"
else
lastlog | grep $(whoami) | awk '{ print $3 }'
fi
}

promptcommand()
{
if [ -n $SSH_CLIENT ]; then
PS1="\[\\e1;31m\\🟢 $(psONEssh)\\[\\e[0m\\]\\[\\e[1;33m\\]\n\w/\n\\[\\e[0m\\]\\[\\e[1;31m\\]𝝅 \\[\\e[0m\\]\\[\\e[1;32m\\] "
else
ss -tn src :8222 | grep ESTAB &> /dev/null
if [ $? -ne "1" ]; then
PS1="\\[\\e[1;31m\\]🟢 $(psONElocal)\[\\e1;33m\\\n\w/\n\[\\e0m\\\[\\e1;31m\\𝝅\[\\e0m\\\[\\e1;32m\\ "
else
PS1="\[\\e1;31m\\🔴

Boredom PS1 project

I decided I was going to learn a bit more about the `PS1` prompt. I started out with a nice easy prompt with `\w` on one line and the prompt with a custom user token `𝝅` rather than the stock `$` on the next.

I liked the setup a lot, so I used the same configuration on my home work station and the termux installation on my phone.

The setup worked great until I started running the wrong commands on the wrong system. For good reason, as the prompts were identical, I decided to see if I could setup my prompt to show a different prompt for an ssh connection.

I had a fun time getting that to actually work. I was making it more complicated than it needed to be, but wait there's more. Now when I connect to my ssh server it shows the IP address of the login before last rather than the current login. With a remote login it is kind of useless to see that you just logged in but it is useful to see if someone logged in before you... Just in case you know.

Once I got that working I decided to take it to a whole new level of ridiculous... Solely because why not. I wanted to see what it would take to show in my local terminal that there was an active connection. Next was to make the command search for an active connection on my SSH port, if one was active it ran one prompt and if no connection, another. it took some trial and error to get that running correctly. Once it was running, I found that it would only update when a new terminal session was opened or if I sourced .bashrc. Which in and of itself wasn't that bad but there had to be a way to get that info without sourcing or starting a new terminal session.

After a bit more trial and error and research on the topic i found the answer to getting that info to update after each command. The `PROMPT_COMMAND` setting was what did the trick. By wrapping the whole command into a function i was able to call it in the `PROMPT_COMMAND` which gets evaluated after every command runs.

Now not only will it show an active connection, it will show the last IP to login to that users account. It will also search through a predefined list of known IP addresses and if they match the IP address will be green to denote a known IP and display a custom string so you don't have to look at your own IP addresses. If it returns an unknown IP address it will turn red.

Then to add the finishing touches to this ridiculous project, a red/green light for inactive/active connections respectively, just because I could

I'd like to hear how you all would make it better/different. It was a fun project to learn about the prompt and make sure I used proper escaping. So here is my absolutely, totally, over the top, unnecessary PS1 prompt. Complete with functions and PROMPT\_COMMAND

&#x200B;

# This will show if there is an active SSH connection after each command is executed.
# Shows second to last login of current user; best used with AllowUsers in sshd_config
psONE_ssh()
{
if [[ "$(last | sed -n '2p' | awk '{ print $3 }')" =~ ("XXX.XXX."*|"XXX.XXX.XXX.XXX"|"XXX.XXX.XXX.XXX"|"XXX.XXX.XXX.XXX") ]]; then
printf %b "\\[\\e[1;32m\\]KNOWN CONNECTION\n"
else
last | sed -n '2p' | awk '{ print $3 }'
fi
}

psONE_local() # Shows the last login from the current user; best used with AllowUsers in sshd_config
{
if [[ "$(lastlog | grep $(whoami) | awk '{ print $3 }')" =~ ("XXX.XXX."*|"XXX.XXX.XXX.XXX"|"XXX.XXX.XXX.XXX"|"XXX.XXX.XXX.XXX") ]]; then
printf %b "\\[\\e[1;32m\\]KNOWN CONNECTION\n"
else
lastlog | grep $(whoami) | awk '{ print $3 }'
fi
}

_prompt_command()
{
if [[ -n $SSH_CLIENT ]]; then
PS1="\\[\\e[1;31m\\]🟢 $(psONE_ssh)\\[\\e[0m\\]\\[\\e[1;33m\\]\n\w/\n\\[\\e[0m\\]\\[\\e[1;31m\\]𝝅 \\[\\e[0m\\]\\[\\e[1;32m\\] "
else
ss -tn src :8222 | grep ESTAB &> /dev/null
if [ $? -ne "1" ]; then
PS1="\\[\\e[1;31m\\]🟢 $(psONE_local)\\[\\e[1;33m\\]\n\w/\n\\[\\e[0m\\]\\[\\e[1;31m\\]𝝅\\[\\e[0m\\]\\[\\e[1;32m\\] "
else
PS1="\\[\\e[1;31m\\]🔴

$(psONE_local)\\[\\e[1;33m\\]\n\w/\n\\[\\e[0m\\]\\[\\e[1;31m\\]𝝅\\[\\e[0m\\]\\[\\e[1;32m\\] "
}
# This will show if there is an active SSH connection after each command is executed.


PROMPT_COMMAND="_prompt_command; history -n; history -w; history -c; history -r; $PROMPT_COMMAND"

I know this is total overkill but it was fun.

https://redd.it/10kyw1i
@r_bash

Bash noscript says file not found even though the filename is the noscript itself
https://redd.it/10lpwi9
@r_bash

The Ultimate Coding Pal (AI-Powered)

Hey fellas 👋

I wrote CodePal.ai \- A free AI-powered service that provides many coding tools for coders and non-coders to make their life easier. It can code, review code, simplify code, find bugs,, and many more cool features.

My mission is to make coding easier, more accessible and fun for coders and non-coders.

I use this myself to perfect my code pretty often and I find it handy in many cases.

I've put many hours into this and would love to hear your feedback on it ❤️

Thank you!

https://redd.it/10ltuyv
@r_bash

Books or Websites to learn Bash noscripting

Hi I am newbie to Linux, I would like to learn Bash noscripting


Please suggest me some good resources.

https://redd.it/10ltudi
@r_bash

stail.sh - Short Tail

This is a fairly short (59 LOC) utility noscript that allows you to tail the output of a command, but while only showing the last -n (default 5) lines of output without scrolling the output buffer. It will trim lines to the terminal width (rather than wrap them) to avoid splitting terminal escape sequences. You can also optionally -p PREFIX each line of output. Finally, it (by default) removes blank/whitespaces lines, but they can be preserved with -w.

Video here.

https://reddit.com/link/10m102l/video/0y2nzxf22gea1/player

Code on GitHub Gist.

https://redd.it/10m102l
@r_bash

Read won't take any userinput except one

https://redd.it/10m4ave
@r_bash

Bash oneliner

What is your favourite bash oneliner?

https://redd.it/10m7pml
@r_bash

shell...???

What is the website I'm thinking of!!!??? We use it all the time for bash noscripting, and I can not figure it outt. I'm pretty sure it's shell something, but nothing so far sounds right. Can anyone help me or at least explain what this is doing, I get the general idea, but I'm curious how it helps make noscripts ready for reddit.

echo ; sed 's/^/ /' noscript.sh

https://redd.it/10mepie
@r_bash

Help with a scheduled (cron) bash noscript

Hi everyone, I’m new to this sub so I apologize in advance for any mistakes.

I created a noscript that checks if a python application is running and if not starts it. This is what it looks like:

#!/bin/bash
if pgrep -x "python3.10" > /dev/null
then
echo "Application is running."
else
source dev/bin/activate
cd dev
nohup python3.10 main.py > output.log 2>&1 &
echo "Application restarted."
fi`

This code works perfectly fine when I run it from the terminal, however, when I try to run it using cron I get the correct output but main.py doesn’t actually start.

I’m not sure what I’m doing wrong. Any help would be appreciated!

https://redd.it/10mjh9x
@r_bash