linux - how to store result of tail command in variable? -

i developing application in mean stack. want create script of image resizing & cropping background process when new image uploads server.

script watches new image uploads in folder , crop it.

i preferred way of linux shell scripting daemon.

i have used following idea accomplished tasks. - new image uploads on server writes in photolog.txt file, can grab images line line. - read photolog.txt in watch.sh shell scripting file. - iterates through line line, until reaches eol. - again new file arrives append @ eol. - manage updated file tail command, , latest add file display in command-line. upto code works charm.

now grab image list of newly added file on server. main issue fails store output of tail command in variable, , must me because whatever output full path of filename , use in imagemagick crop command.

imagemagick center crop scale image.

convert -define file-type:size=widthxheight original_filename -thumbnail 120x120^ -gravity center -extent 100x100 resize_filename

watch.sh

#!/bin/bash path="/var/www/html/appbite/trunk/photolog.txt" cat $path | \  until false     # if file exists      if [[ -f "$path" ]]                 while ifs= read -r photo                     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 

i grab command-line output not able store value in variable, next use imagemagick image processing command.

or suggest me other way continuous monitoring folder newly added file list.

since tail -f doesn't terminate, don't want capture output in variable. since call in loop anyway, call on , on this:

out=`tail "$path"` 

or using modern syntax:

out=$(tail "$path")