Based on Nat Friedman's https://coderwall.com/p/y5eiiq

gistfile1.txt

#!/bin/sh

SCP_USER='user'
SCP_HOST='host'
SCP_PASS='pass'
SCP_PATH='/path/to/file'

HTTP_URL="http://url"

FILENAME=`(cat /dev/random|head -c 10; date) | md5 -q | head -c 10`.png
FILEPATH=/tmp/$FILENAME

screencapture -i $@ $FILEPATH
if [ -f $FILEPATH ]
then
    echo $HTTP_URL$FILENAME | pbcopy
    sshpass -p ${SCP_PASS} scp $FILEPATH ${SCP_USER}@${SCP_HOST}:$SCP_PATH
    rm $FILEPATH

    echo `date` $HTTP_URL$FILENAME >> ~/bin/sattap.log
fi