How to use the getopts builtin with optional arguements.

Hi all, I'm working on a bash-only noscript (that you'll likely see posted here in a bit), and wanted to use getopts with optional arguements. this question was asked on stack overflow, but the top answer seemed overly verbose/unclear, so I thought I'd share my solution. It meerly requires two tests at the start of processing, and then checking wether OPTARG is null or not for the respective arguement. The only 'gotcha' is that you can't use arguements that start with a dash.

#! /bin/bash
while getopts ':abc:d:f' opt; do # use silent reporting with a ':' at the start of `optstring`
   if [[ $opt == ':' ]]; then 
      # `opt` is set to ':' if an option is missing a specified argument
      # and `OPTARG` is set to the option with a 'missing' argument
      opt="$OPTARG"
      unset OPTARG
   elif [[ $OPTARG =~ ^- ]]; then       
      # unless the option with a potential argument comes last, this is needed to filter
      # out any following options
      ((OPTIND--))
      unset OPTARG
   fi
   #shellcheck disable=SC2220
   case "$opt" in 
      a)
         echo "opt: a"
         ;;
      b)
         echo "opt: b"
         ;;
      c) 
         #echo "opt: c"
         if [[ -z $OPTARG ]]; then
            C="Hello there."
         else
            C="$OPTARG"
         fi
         ;;
      d)
         #echo "opt: d"
         if [[ -z $OPTARG ]]; then
            D="efault."
         else
            D="$OPTARG"
         fi
         ;;
      f)
         echo "opt: f"
         ;;
   esac 
done 
echo "$C"
echo "$D"

So (assuming the noscript is name getopts.sh), running

$ ./getopt.sh -c -d "General Kanobi!"

will return

Hello there.
General Kanobi!

EDIT: I threw in some comments giving a bit more of an explination.

https://redd.it/182e35x
@r_bash

Kill, an interactive bash-only noscript for killing processes/sending signals.

Small, interactive, bash-only noscript I made that (naturally) uses the 'kill' builtin. Apart from sending signals, it can also list the environment of a selected process sans 'LSCOLORS' (as the value of LSCOLORS is generally not helpful and is visually distracting). All you need to do is clone it and make it executable:) Link: https://github.com/unsigned-enby/Kill

https://redd.it/182hvgp
@r_bash

How to process only a specific input file with AWK?

I am trying to write a AWK noscript for some data processing and I am passing 3 input files to it. I am trying to figure out how to process only the third input file at a certain point of the noscript so I can create an array called compare. I have a for loop that looks for protocols in a topprotos array , so there will be about 10 protocols in that array. Lets name them proto1 , proto2 , proto3 and so on...My 3rd input file has 4 fields in each line, first being a protocol and third being a value. fields 2 and 4 aren't relevant. But what I want to do is loop through the topprotos items and find lines in this file where the first field matches. So if we do "for protocol in topprotos" and protocol in this iteration is proto5 , I want to look for the lines in my 3rd input file that have the first field as "proto5" , now all these lines that match have the 3rd field value , I want to sum all these values together and then append it to compare. So for each iteration I will have something like compare[protocol\] += $3 , and if you do a print of something like "print protocol " " compare[protocol\]" in the loop after appending you should see all the iterations with there values like this.


proto1 200

proto2 400

proto3 100

proto4 500

proto5 230

​

and so on...


here is a pastebin to my code https://pastebin.com/THfm6qfj


if anyone could help me I would really appreciate it !!!

https://redd.it/182xeng
@r_bash

emulating the full functionality of the history command with arrow key navigation within bash noscript

I am looking for a constant interactivity within a noscript allowing me as user to navigate and execute previous commands by using arrow keys.   I have tried read and select but no way I get the history feature with arrow keys as we have in the bash shell. Any indea what command I can use? Thanks

https://redd.it/183a4qm
@r_bash

Help choosing Bash alias and function names that WON'T come back to bite you later!

https://github.com/makesourcenotcode/name-safe-in-bash

https://redd.it/183blrk
@r_bash

What Bash noscripts to know when working in a Cloud job?

Just passed my AWS Cloud Architect exam and now learning Bash. I am a complete beginner and have watched a few YouTube videos but can't seem to find any that focus on when working in the Cloud, just the basics.

If anyone has any examples of what would be expected to know when working with Cloud, I would be very grateful.

https://redd.it/183mhfb
@r_bash

Help with Bash noscript

Hi! I'm quite new to bash noscripting so this may seem like a bit of a newbie question but I'm having a bit of trouble with a noscript I just wrote, I've been playing around and tinkering around with it for a while but it still doesn't seem to do what I want it to, here's the noscript:

#!/bin/sh

url=$(firefox "$(cat ~/stor/bcomp/urls | dmenu)")
if -z $url
then
exit 0
else
firefox "$(cat ~/stor/bcomp/urls | dmenu)"
fi

exit

The main function of the noscript was to just act as a collection of bookmarks which is selected to be opened by firefox by piping the urls into dmenu. That works just fine. The only problem is that it creates a new Firefox instance when I exit dmenu. Is there any other way I could go about notifying the noscript if there's any input from the user from dmenu? I would really appreciate the help!

https://redd.it/183o9z1
@r_bash

List to php array

Hi guys,

we have a shared nextcloud for the entire company, the users are syncing with the desktop client. Sometimes a ransomware infection happen and the sync client see: "oh! there's a change on this file. I need to sync this!" The last unencrypted files (in the cloud) get encrypted too. I could use the build-in feature 'blacklisted_files' with this list. The final array looks like this:

<?php
$CONFIG = array (
array (
0 => '.htaccess',
1 => 'Thumbs.db',
2 => 'thumbs.db',
),
);

Nextcloud can have multiple *.config.php files, they get merged, so I can provide an exclusive blacklist file. I want to get this extension list every day and put that into the array above. sed and awk are nice tools, but can they insert a enumeration too?

&#x200B;

https://redd.it/1843o1q
@r_bash

Function that automatically resubmits last command with "--help" instead of "-h"
https://i.vgy.me/P8v1aY.png

https://redd.it/1849by3
@r_bash

Bash Sugar ( a bash threads)

There used to be a bash thread, now there's not.

Lets change that.

Here's a thing for expanding aliases in zsh

#-------------------------------
# ealias
#-------------------------------
typeset -a ealiases
ealiases=()

function ealias()
{
alias $1
ealiases+=(${1%%\=*})
}

function expand-ealias()
{
if [[ $LBUFFER =~ "(^|[;|&])\s*(${(j:|:)ealiases})\$" ]]; then
zle _expand_alias
zle expand-word
fi
zle magic-space
}

zle -N expand-ealias
bindkey -M viins ' '    expand-ealias
bindkey -M viins '^ '   magic-space     # control-space to bypass completion
bindkey -M isearch " "  magic-space # normal space during searches
#-------------------------
ealias gc='git commit . -m '
ealias gp='git push'

https://redd.it/1858sjf
@r_bash

Using a shell noscript to check if one file's variable contents exist in another?

Hi everyone, kind of new to shell noscripting, so in a CSV file I have two fields "ip addresses," and the "timestamp." When it comes to the destination IP field, to narrow/return only that field and all the associated IPs I used use

cat files.csv | cut -d "," -f 1 file.csv

and I stored this to a variable value, lets call it IP=$(cat files.csv | cut -d "," -f 1 file.csv)

For the timestamp, I did something similar, and also stored it to a variable value

cat file.csv | cut -d "," -f 2 file.csv

timestamp=$(cat files.csv | cut -d "," -f 2 file.csv)

Now, with these variables for the destination IP and the timestamp, how would I go about using a shell noscript to see if both of these variable values (the specific destination ips, and the timestamp as well), exist in the json.logs file (the file which the values of the CSV would be checking against from my shell noscript). I would then return the lines of the json.logs file where there is a match, and output it to a new file.

https://redd.it/18584kc
@r_bash

Help pls boss??
https://redd.it/185na7d
@r_bash

Using tail to pipe stdin ?

I wanted to update a yad notification with data from a subshell, so I tried using an external temporary file; I had various issues trying to do this, then tried this:

yad --notification --listen < <(tail -f -n1 $TMP 2>/dev/null | cat)

( $TMP is a tempfile where another part of the noscript put updates for the notification ; pipe to cat seems needed to avoid "buffering issues" ... )
It seems to work nicely, it's someway wrong to do this?

https://redd.it/18686zs
@r_bash

Does anyone know how to highlight specific characters when pasting output from a text file?

I'm making a wrapper for ncal that, just for fun, replaces the month, year, and weekday abbreviations with those from The Elder Scrolls (kind of a fun "to see if I could" project). I've used 'ncal -C' to do this, and I've sorted out most of the process, redirecting output to a text file, using sed to replace the month/year header and the day abbreviations, but there's one thing I can't seem to figure out how to do, and that's changing the text style of the current day to be black on white when catting out the .tmpdate file after making the changes to the first two lines with sed, so the current date is highlighted as normal with 'ncal-C'. I've worked with ChatGPT to see if it can get it to do it, but nothing it comes up with has worked.

Currently have this as what was last tried to highlight the current date:
`awk -v today="$(date +'%e')" '{gsub(/\\y'"$today"'\\y/, "\\033[1;31m&\\033[0m")}1' .tmpdate`
Though that doesn't do much more that `tail -n +2 .tmpdate`

Any thoughts would be welcome


https://redd.it/186c3fa
@r_bash

How to create argument suggestion for a programme?

I was wondering how one could replicate the default behaviour of many bash utilities, that show all available arguments after writting -+Tab.

https://redd.it/186mlii
@r_bash

Why is my bash for loop printing from the end?

Here is my code -

```declare -A mydict=(["key1"\]="value1"["key2"\]="value2")

for arg in "${!mydict[@\]}"; dojson_string="{\\"$arg\\":\\"${mydict[$arg\]}\\"}"echo $json_stringdone

```

This is the output -

```{"key2":"value2"}

{"key1":"value1"}

```

I was expecting it to do -

```{"key1":"value1"}

{"key2":"value2"}

&#x200B;

```

https://redd.it/186rdhf
@r_bash

Wildcard to only match certain files ?

So I am trying to create a wildcard that will only match certain files but I am not sure how to do so. In my dir the files look like this

10.0.0.1.csv
10.0.0.2.csv
10.0.0.3.csv
10.0.0.4.csv
10.0.0.5.csv
10.0.0.6.csv
10.0.0.7.csv
10.0.0.8.csv
10.0.0.9.csv
10.0.0.10.csv
toplist.csv
usage.csv
trial.csv


I only want to match the files with the IP addresses in their names , but the IP address in the filename may change. How can I accomplish this ?

https://redd.it/186tv00
@r_bash

A single function to extract all archive file types at once: tar{gz,tgz,xz,lz,bz2} + zip and 7z

####################################################################################
##
## How to demonstrate:
##
### 1) Add all of the following types of archives to an empty directory
## - name.tar.gz
## - name.tar.tgz
## - name.tar.xz
## - name.tar.bz2
## - name.tar.lz
## - name.zip
## - name.7z
##
## 2) Add the untar function to your .bash_functions or .bashrc file and source it or restart your terminal
##
## 3) Simply type "untar" in the same directory as the above archive files
## - Second method is to run this noscript in the same direcotry with the archive files using the command "bash untar.sh"
##
## Result: All archives will be extracted and ready to use
##
####################################################################################

You need 7z installed for the 7z and zip archive files and tar command for the tar files.

Also for the lz tar files you can install it using `sudo apt install lzip`

If you like you can use my GitHub 7zip noscript to instantly install the latest 7zip version 23.01.

bash <(curl -fsSL https://7z.optimizethis.net)

[GitHub Script: 7-zip installer](https://github.com/slyfox1186/noscript-repo/blob/main/Bash/Installer%20Scripts/SlyFox1186%20Scripts/build-7zip)

I hope you guys think it's worthy!

Cheers!

[GitHub Script: untar.sh](https://github.com/slyfox1186/noscript-repo/blob/main/Bash/Misc/untar.sh)

https://redd.it/186zwdp
@r_bash

Bash projects

What are some bash projects that you would think as a “trophy” in a resume/ or that have some potential in general (I’m mostly interested in blue team/ red team related projects).

https://redd.it/186zu8j
@r_bash

How to return lines from a JSON log file which contain matched IPs and timestamps values from a CSV?

IP and timestamp values exists in some way in the line entries of the JSON log file, and if so, return that specific JSON log entry to another file. I tried to make it universal so it's applicable to all IP addresses. Here's what the sample CSV file would look like;

"clientip,""destip","desthostname","timestamp"
"127.0.0.1","0.0.0.0","randomhost","2023-09-09T04:18:22.542Z"

And a sample line entry from the Json Log File

{"log": "09-Sept-2023 rate-limit: info: client @xyz 127.0.0.1, "stream":"stderr", "time": 2023-09-09T04:18:22.542Z"}

It's the lines from the JSON log file we want to return in the output.txt file when there's a match. The JSON file doesn't have the same fields and organization like the CSV does (with clientip, destip, dest\hostname, timestamp, but I was hoping that I could still at least return lines from the JSON log files to a new file that had matches on the clientip (like we see here with 127.0.0.1 in "info: client @xyz 127.0.0.1) and maybe the timestamp.

I tried using the join command like, join file.csv xyz-json.log > output.txt . Andawk did not yield much either.

https://redd.it/1877qzz
@r_bash

set -e, but show error message and line-number

I usually use set -e in my bash noscripts.

Unfortunately, you only get a non-zero exit value if a command fails, but no warning message.

Is there a simple way to get and error message and the line-number, if
a bash noscript stops because a command returned a non-zero status?

https://redd.it/187fr0c
@r_bash