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Simple scripts I made over time

Author: Solène
Date: 19 July 2021
Tags: openbsd scripts shell

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Introduction

I wanted to share a few scripts of mine for some time, here they are!

Scripts

Over time I'm writing a few scripts to help me in some tasks, they are often associated to a key binding or at least in my ~/bin/ directory that I add to my $PATH.

Screenshot of a region and upload

When I want to share something displayed on my screen, I use my simple "screen_up.sh" script (super+r) that will do the following:

use scrot and let me select an area on the screen
convert the file in jpg but also png compression using pngquant and pick the smallest file
upload the file to my remote server in a directory where files older than 3 days are cleaned (using find -ctime -type f -delete)
put the link in the clipboard and show a notification

This simple script has been improved a lot over time like getting a feedback of the result or picking the smallest file from various combinations.

#!/bin/sh
test -f /tmp/capture.png && rm /tmp/capture.png
scrot -s /tmp/capture.png
pngquant -f /tmp/capture.png
convert /tmp/capture-fs8.png /tmp/capture.jpg
FILE=$(ls -1Sr /tmp/capture* | head -n 1)
EXTENSION=${FILE##*.}

MD5=$(md5 -b "$FILE" | awk '{ print $4 }' | tr -d '/+=' )

ls -l $MD5

scp $FILE perso.pw:/var/www/htdocs/solene/i/${MD5}.${EXTENSION}
URL="https://perso.pw/i/${MD5}.${EXTENSION}"
echo "$URL" | xclip -selection clipboard

notify-send -u low $URL

Uploading a file temporarily

Second most used script of mine is a uploading file utility. It will rename a file using the content md5 hash but keeping the extension and will upload it in a directory on my server where it will be deleted after a few days from a crontab. Once the transfer is finished, I get a notification and the url in my clipboard.

#!/bin/sh
FILE="$1"

if [ -z "$1" ]
then
        echo "usage: [file]"
        exit 1
fi
                
                
MD5=$(md5 -b "$1" | awk '{ print $NF }' | tr -d '/+=' )
NAME=${MD5}.${FILE##*.}

scp "$FILE" perso.pw:/var/www/htdocs/solene/f/${NAME}

URL="https://perso.pw/f/${NAME}"
echo -n "$URL" | xclip -selection clipboard

notify-send -u low "$URL"

Sharing some text or code snippets

While I can easily transfer files, sometimes I need to share a snippet of code or a whole file but I want to ease the reader work and display the content in an html page instead of sharing an extension file that will be downloaded. I don't put those files in a cleaned directory and I require a name to give some clues about the content to potential readers. The remote directory contains a highlight.js library used to use syntactic coloration, hence I pass the text language to use the coloration.

#!/bin/sh

if [ "$#" -eq 0 ]
then
        echo "usage: language [name] [path]"
        exit 1
fi

cat > /tmp/paste_upload <<EOF
<html>
<head>
<meta http-equiv="Content-type" content="text/html; charset=utf-8" />
</head>
<body>
        <link rel="stylesheet" href="default.min.css">
        <script src="highlight.min.js"></script>
        <script>hljs.initHighlightingOnLoad();</script>

        <pre><code class="$1">
EOF

# ugly but it works
cat /tmp/paste_upload | tr -d '\n' > /tmp/paste_upload_tmp
mv /tmp/paste_upload_tmp /tmp/paste_upload

if [ -f "$3" ]
then
    cat "$3" | sed 's/</\&lt;/g' | sed 's/>/\&gt;/g' >> /tmp/paste_upload
else
    xclip -o | sed 's/</\&lt;/g' | sed 's/>/\&gt;/g' >> /tmp/paste_upload
fi


cat >> /tmp/paste_upload <<EOF


</code></pre> </body> </html>
EOF


if [ -n "$2" ]
then
    NAME="$2"
else
    NAME=temp
fi

FILE=$(date +%s)_${1}_${NAME}.html

scp /tmp/paste_upload perso.pw:/var/www/htdocs/solene/prog/${FILE}

echo -n "https://perso.pw/prog/${FILE}" | xclip -selection clipboard
notify-send -u low "https://perso.pw/prog/${FILE}"

Resize a picture

I never remember how to resize a picture so I made a one line script to not have to remember about it, I could have used a shell function for this kind of job.

#!/bin/sh

if [ -z "$2" ]
then
	PERCENT="40%"
else
	PERCENT="$2"
fi

convert -resize "$PERCENT" "$1" "tn_${1}"

Latency meter using DNS

Because UDP requests are not reliable they make a good choice for testing network access reliability and performance. I used this as part of my stumpwm window manager bar to get the history of my internet access quality while in a high speed train.

The output uses three characters to tell if it's under a threshold (it works fine), between two threshold (not good quality) or higher than the second one (meaning high latency) or even a network failure.

The default timeout is 1s, if it works, under 60ms you get a "_", between 60ms and 150ms you get a "-" and beyond 150ms you get a "¯", if the network is failure you see a "N".

For example, if your quality is getting worse until it breaks and then works, it may look like this: _-¯¯NNNNN-____-_______ My LISP code was taking care of accumulating the values and only retaining the n values I wanted as history.

Why would you want to do that? Because I was bored in a train. But also, when network is fine, it's time to sync mails or refresh that failed web request to get an important documentation page.

#!/bin/sh

dig perso.pw @9.9.9.9  +timeout=1 | tee /tmp/latencecheck

if [ $? -eq 0 ]
then
        time=$(awk '/Query time/{
                if($4 < 60) { print "_";}
                if($4 >= 60 && $4 <= 150) { print "-"; }
                if($4 > 150) { print "¯"; }
        }' /tmp/latencecheck)
        echo $time | tee /tmp/latenceresult
else
        echo "N" | tee /tmp/latenceresult
    exit 1
fi

Conclusion

Those scripts are part of my habits, I'm a bit lost when I don't have them because I always feel they are available at hand. While they don't bring much benefits, it's quality of life and it's fun to hack on small easy pieces of programs to achieve a simple purpose. I'm glad to share those.