shell script to run pyflakes on all python files in a git diff

difflake.sh

#!/bin/bash

PYFLAKES=$(which pyflakes)
GIT=$(which git)
BRANCH=$($GIT rev-parse --abbrev-ref HEAD)

if [ $# -eq 0 ]
  then
    echo "No arguments supplied, please provide atleast 1 branch or commit hash. SYNTAX: difflakes [src] [dst]"
    exit;
fi

if [ "$1" != "master" ]; then
	A=$1
else
	A='master'
fi

if [ -z "$2" ]; then
	B=$BRANCH
else
	B=$2
fi

echo "running pyflakes on diff between $A and $B"

pyflakes $(git diff $A..$B --name-only | grep \.py$)