Shell Script Output not written to file properly

Question

I tried to put the output of my program into a text file. It appends the echo commands to the file properly, but the imagemagick "compare" command is not appended to the file. It just STOUD's the "PSNR value", which is returned by compare method into terminal.

Is there a way to append this commands output to the textfile too? Also if I call my script just with "./script.sh > test.txt" it doesn't print anything more than the echos to file and compare results to terminal.

Here's a part of my code:

ls images/toconvert/ > lsout.txt

while read LINE
do
    echo ====================== $LINE ==================== >> psnrdiff.txt
    echo Jpeg2000 >>  psnrdiff.txt
    compare -metric PSNR images/toconvert/$LINE images/converted/$LINE.jp2 images/psnrDiffs/$LINE.jp2.png >> psnrdiff.txt
done < lsout.txt

Answer 1

Various imagemagick command output to STDERR instead of STDOUT.

You can redirect STDERR to STDOUT to capture the output:

compare -metric PSNR .... >> psnrdiff.txt 2>&1

Answer 2

ls images/toconvert/ > file.txt 
while read LINE
do
    echo ====================== $LINE ==================== >> psnrdiff.txt
    echo Jpeg2000 >>  psnrdiff.txt
    compare -metric PSNR "images/toconvert/$LINE" "images/converted/$LINE.jp2" "images/psnrDiffs/$LINE.jp2.png" >> psnrdiff.txt
done < file.txt