how to store result of tail command in variable?
<p>I am developing application in MEAN stack. I want to create a script of image resizing &amp; cropping as a background process when new image uploads to server.</p>

<p>Script watches new image uploads in folder and crop it.</p>

<p>I preferred way of Linux shell scripting as daemon.</p>

<p>I have used following idea to accomplished tasks.
   - New image uploads on server it writes in photolog.txt file, where I can grab images line by line.
   - I read photolog.txt in watch.sh shell scripting file.
   - It Iterates through line by line, until it reaches to the EOL.
   - Again new file arrives it will append at EOL.
   - I manage to get updated file by tail command, and get the latest add file display in command-line. Upto this code it works charm.</p>

<p>Now I am successfully grab the image list of newly added file on server. but main issue is that I fails to store output of tail command in variable, and it must to me because whatever output I get it is full path of filename and it will use in imagemagick crop command.</p>

<p><strong>Imagemagick center crop with scale an image.</strong></p>

<blockquote>
  <p>convert -define <strong>file-type</strong>:size=<strong>widthxheight</strong> <strong>original_filename</strong> -thumbnail 120x120^ -gravity center -extent 100x100 <strong>resize_filename</strong></p>
</blockquote>

<p><strong>watch.sh</strong></p>

<pre><code>#!/bin/bash
path="/var/www/html/AppBite/trunk/photolog.txt"
cat $path | \

until false
do
    # If file exists 
    if [[ -f "$path" ]]
    then    
        while IFS= read -r photo
        do
            imageFormat=`identify $photo | awk '{print $2}'`
            imageScale=`identify $photo | awk '{print $3}'`
            echo "$photo $imageFormat $imageScale"
        done
    fi
    # Continous monitor file changes via commandline
    tail -f $path
done
</code></pre>

<p>I am successfully grab command-line output but I am not able to store value in variable, for next use imagemagick image processing command.</p>

<p>or suggest me other way to continuous monitoring folder to get newly added file list.</p>