loop through dates in a bash script. Also uses a while loop, and if and not/then statements

bash_loop_dates.sh

#!/bin/bash
# loop through dates, using GNU dates
# GNU date reference: https://www.gnu.org/software/coreutils/manual/html_node/Examples-of-date.html

# define paths
open_path=../data/raw
save_path=../data/processed

# define dates
start_date=2020-02-25
end_date=2020-03-04

d=$start
# end date
while [ "$d" -lt 2020-03-04 ]; do
    # define file names, which are based on date
    DATAFILE=$open_path/new_domains_$d.pkl
    SAVEFILE=$save_path/new_domains_predict_$d.pkl
    
    # if DATAFILE exits, but not SAVEFILE
    if [ -f "$DATAFILE" ] &&  [ ! -f "$SAVEFILE" ]
    then
        # run python script
        python3 predict.py -f $DATAFILE -o $SAVEFILE -s -v
    else 
        echo "cannot find $DATAFILE or $SAVEFILE already exists"

    fi
    # increment date
    d=$(date -I -d "$d + 1 day")
done