Adding the value of an array to a variable

Im just learning bash so this question mighta bit stupid. What im trying to do, is to add the values of every colum of an array, that contain 100 letters at maximum, to an Variable and give out the sum. For this i have created the following noscript:

#!/bin/bash
read save[1000]
i=0
sum=0
while (($i < 1000)); do
sum=$(($sum + ${save[$i]}))
((i++))
done
echo $sum

When executing i get the following error message:

line 5: 0 + : syntax error: operand expected (error token is "+ ")

How can i fix this?

https://redd.it/13xry3j
@r_bash

? - The only cheat sheet you need
https://gist.github.com/thingsiplay/69aada6a57f829d9580d7b54f8a207a0

https://redd.it/13xz1kc
@r_bash

Installer noscript for CMake, Ninja, and Meson

I thought I would share my custom installer noscript for the latest GitHub versions of CMake, Ninja, and Meson.

It uses GitHub's API to grab the latest tag version of each repo and will install the static binaries to /usr/local/bin

bash <(curl -sSL https://build-tools.optimizethis.net)

This is my GitHub repo in case anyone wants to check it out before using: GitHub Script Repo

I hope someone finds this useful. (I know apt works but it doesn't install the latest versions usually).

And please let me know if something is wrong so I can make changes. =)

https://redd.it/13xy52n
@r_bash

Maximize Productivity Of The Bash Shell
https://bluz71.github.io/2023/06/02/maximize-productivity-of-the-bash-shell.html

https://redd.it/13y4pg6
@r_bash

I don't understand how this lines with arrays works

Hello guys, we talked about bash arrays in our shell noscripting course and the professor gave us this demonstration of a cool use of bash arrays but I am not able to understand why this works.

declare -A SELECTOR
declare -A SOMEDATA
declare -A OTHERDATA
SELECTORsome='SOMEDATA$KEY'
SELECTORother='OTHERDATA$KEY'
SOMEDATAfirstkey=somefirstvalue
SOMEDATAsecondkey=somesecondvalue
OTHERDATAfirstkey=otherfirstvalue
OTHERDATAsecondkey=othersecondvalue

KEY=firstkey
DATASET=some
echo ${!SELECTOR$DATASET}
#somefirstvalue

As I know, from bash manual:

>It is possible to obtain the keys (indices) of an array as well as the values. ${!name[@\]} and ${!name[*\]} expand to the indices assigned in array variable name. The treatment when in double quotes is similar to the expansion of the special parameters ‘@’ and ‘*’ within double quotes.

How this syntax of getting the assigned keys of an array let you create this dynamic dataset selection? I am not understanding the step-by-step expansions and operations performed by the shell. Also, I would like to know if any known shell noscripts have used this approach to see a more consistent-real use.

Thanks.

https://redd.it/13yabi7
@r_bash

How do I open a dir/filename with cat command?

For simplicity: I have a directory that contains two things: a setup noscript file, and another directory containing a text file with VS Code extensions, one per line. The paths to the two files would be:

~/Downloads/noscripts/setupnoscript

~/Downloads/noscripts/VSCode/extensions.txt

I have this line in the setup noscript from this superuser topic:

cat VSCode/extensions.txt | xargs -n 1 code --install-extension

I get No such file or directory errors when I run this line; despite trying a number of ways to get it to recognize the file like different path prefixes (/, ./, ../) and even putting extensions.txt in the same directory as setupnoscript. Where am I going wrong?

https://redd.it/13ym85l
@r_bash

Script to simply read value give a not found error ?

Hi

I have a quite simple noscript and somehow i can't figure how to fix it.. It give me a not found all the time. If some do see the point...

nano /sbin/tempcpunotif.sh

#!/bin/bash

while true; do

val=$(sensors | awk '/temp1/ {print $2}')

max="+75.0"

if [[ "$val" > "$max" ]]; then

systemctl suspend

fi

sleep 10

clear

sensors

done

exit 0

&#x200B;

Or i try with a simpler one, but not sure as i told me the temp is not found..:

&#x200B;

#!/bin/sh

# Threshold for when to send alert

threshold=75000

&#x200B;

#sensors | grep -e "Package id 0" | while read line; do

cat /sys/devices/platform/coretemp.0/hwmon/hwmon1/temp1_input | while read line; do

temp=$(echo $line | awk -F "+" '{ print $2 }' | awk -F "." '{ print $1 }');

if (( temp > $threshold )); then sh /sbin/tempnotif.sh

fi;

done

&#x200B;

Thanks in advance

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

woman - Preview list for man documents
https://gist.github.com/thingsiplay/f71383569c10da17f772b9967f5a5767

https://redd.it/13z41ji
@r_bash

What is this command?

I have a noscript that should run only when certain directory exists. It begins like that:

-d /home/path/to/directory &&

I found that example somewhere and it works, but I don't understand what these brackets really do. Is it correct way?

https://redd.it/13z8dfl
@r_bash

Curious Bash: Get Notified When It's Done
https://blog.carlolobrano.com/posts/2023-06-02-curious-bash-get-notified-when-done/

https://redd.it/13zj9ly
@r_bash

Run a noscript into a new "less" istance then go back to the normal shell when the noscript has finished

Scenario: I want run a noscript into a terminal window, but to keep this window "clean" (ie I want to display only START and FINISHED) I want to display all the outputs into a clean space (like into the "less" command or even by opening it in "xterm"), then when the noscript has finisced I want to come back to the terminal window, automatically, so without having to press a key (like Q in "less"). All I want to see on that window is START and FINISCED! Nothing more. How should I do? I'm going mad!

https://redd.it/13zo2g6
@r_bash

Idempotent mutation of PATH-like env variables

It always bothered me that every example of altering colon-separated values in an environment variable such as PATH or LD_LIBRARY_PATH (usually by prepending a new value) wouldn't bother to check if it was already in there and delete it if so, leading to garbage entries and violating idempotency (in other words, re-running the same command WOULD NOT result in the same value, it would duplicate the entry). So I present to you, prepend_path:

# function to prepend paths in an idempotent way

prependpath() {
local dir="${1%/}" # discard trailing slash
local var="${2:-PATH}"
if [ -z "$dir" ]; then
echo "Usage: prependpath <pathtoprepend> name_of_path_var" >&2
return 2 # incorrect usage return code, may be an informal standard
fi
local newvalue=${!var}
[ $newvalue =~ ^$dir: ] && return # quit if value already starts with $dir
newvalue=${newvalue%:$dir} # remove $dir from end of path
newvalue=${newvalue//:$dir:/:} # remove $dir from middle of path
# prepend the new entry
export ${var}="$dir:$newvalue"
}

Usage examples:

prependpath $HOME/.linuxbrew/lib LDLIBRARYPATH
prependpath $HOME/.nix-profile/bin

Note that of course the order matters; the last one to be prepended that matches, triggers first, since it's put earlier in the PATHlike. Also, due to the use of some Bash-only features (I believe) such as the ${!var} construct, it's only being posted to /r/bash =)

EDIT: code modified per /u/rustyflavor 's recommendations, which were good. thanks!!

https://redd.it/13zmp3w
@r_bash

How to recursively rename photographs/videos to their respective folder name

To preface, I'm very new to bash. I have several thousand photographs and videos that I imported from Photos (macOS) and they were stored in folders based on their date. I'm not on Fedora and using gThumb and I cannot view all of my photographs/videos at once since there are so many sub-folders. I'd like to have them all in one folder, but still organized. So, as the noscript states, I'd like help writing a noscript that could recursively scan a directory (including one tier of sub-folders) and rename each photograph/video to the respective directory. Even better if it could remove any alphabetical letters.

Here's an example of a directory: Christmas Eve, December 24, 2018

Here's an example of what I'd like the files to be named: 12-24-2018 (1), 12-24-2018 (2), etc.

This way all of my photographs/videos could be stored in one folder.

Here's something I had tried:

#!/bin/bash

for i in ~/Pictures/*/*.png;

do $parentFolder = dirname $i;

mv $i $parentFolder.png;

echo "Renamed $i to $parentFolder.png";

done

It obviously doesn't work, but I'd appreciate any help in fixing my errors.

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

Shell Scripting Tutorial
https://www.shellnoscript.sh/

https://redd.it/140hz7l
@r_bash

these lines causing errors but I swear they weren't causing error before and I didn't change anything

i=0
while read l
do
varr=$(printf "$l" | awk --field-separator="|" "{ print NF }" )
"$varr" -eq 2 || "$varr" -eq 4 || i=$((i+2))

done < file

the error is this

[: Illegal number:

https://redd.it/140q88d
@r_bash

Dispatcher does nothing on my machine?

I am using this commonly known noscript which isn't working for me at all. As in, no output and no changes in WiFi status:

&#x200B;

#!/bin/bash

enabledisablewifi ()
{
result=$(nmcli dev | grep "ethernet" | grep -w "connected")
if -n "$result" ; then
nmcli radio wifi off
# echo "off"
else
nmcli radio wifi on
# echo "on"
fi
}

if "$2" = "up" ; then
enabledisablewifi
fi

if "$2" = "down" ; then
enabledisablewifi
fi

This is my output of "nmcli dev | grep "ethernet" | grep -w "connected"

enp52s0f3u1u3u4 ethernet connected My Ethernet

What am I doing wrong? :o

https://redd.it/1414kpb
@r_bash

npid - Get name of process by pid
https://github.com/thingsiplay/npid

https://redd.it/141fs84
@r_bash

printf not completely converted

numbers="50 75"

thistime=$(( $(date +%s)+$(printf '%d' "$numbers" | awk '{print $1}') ))

printf: 50 75: not completely converted

&#x200B;

thisTime should be equal to the current time in seconds (since 1970) + 50

https://redd.it/141ly34
@r_bash

#!/usr/bin/bash -eu

Can someone explain what the -eu means in this example please?

I see it mostly at the beginning of shell noscripts, etc.

Thanks.

https://redd.it/141ry2f
@r_bash

awk just printing what I want it to append in the console instead of actually appending it

awk -v mynum="$(mynumber)" -F ',' 'NF==2{print $0" , -5 , mynum , 3 "}' file

so if there is one comma on a line, it should turn

a ,b

to

a , b , -5, mynum , 3

I don't understand why this doesn't work

https://redd.it/141xsra
@r_bash

Terminal acts sporadic at times

If I run a command $ while ! ping -c 1 -W 1 1.1.1.1; do echo "still waiting for 1.1.1.1" sleep 1 done and I recall it with the up arrow or I recopy and paste it, the order of the command comes up in a weird order and there is no dollar sign preceding the command like such still waiting for 1.1.1.1" sleep 1 done while ! ping -c 1 -W 1 1.1.1.1; do echo ". Also when I press backspace, it clears what I inputted but then it continues to clear what I've entered previously in "history", the backspace doesn't stop at the end of the line, it continues onto the previous lines (as if the screen is a giant txt file). I've had this issue come up in git bash as well. When I reopen my terminal this issue is resolved. It seems like a common issue and I've entered some sort of mode but I don't know how to fix it besides restarting the terminal. Any help would be appreciated.

https://redd.it/141xccx
@r_bash