Why fails the comparsion between two identical version numbers in this script?

Question

I try to compare in a Script two different version numbers of Drupal via drush status. The result should be printed out in a if-else. I made a minimal example:

# put paths in vars
WEBSITE_ROOT_LIVE=/PATH/TO/LIVE
WEBSITE_ROOT_TEST=/PATH/TO/DEV

# get the drupal version line from drupal status output
cd $WEBSITE_ROOT_TEST
test=$(drush status | grep "Drupal version")
cd $WEBSITE_ROOT_LIVE
live=$(drush status | grep "Drupal version")

# count chars in output
wc -c <<< $live
wc -c <<< $test

# print variables
echo $live
echo $test

# compare
if [ "$test" != "$live" ]
then
    echo "not equal"
else
    
    echo "equal"
fi

Strangely this is the output:

84
88
Drupal version : 9.5.0
Drupal version : 9.5.0
not equal

The difference in characters is the explanation, but why are they different? On one side the string has not so much chars, on the other side they are different length. Why is that so, and how can i fix this? I suspect the substitution within the shells $() syntax.

Answer 1

The standard output of Drush is for humans.

For scripts use the Drush output options to select the field and output a string value:

drush status --fields=drupal-version --format=string

or shorter with --field=FIELD to select just one field, and force format to string.

drush status --field=drupal-version

See drush help status.