Git squash and rebase branch into a single commit branch

prbr.sh

#!/bin/bash
set -e

git fetch

BRANCH=$(git rev-parse --abbrev-ref HEAD)
NEWBRANCH="$BRANCH-pr"

if [[ -n $(git rev-parse --verify $NEWBRANCH) ]]; then
    read -p "'$NEWBRANCH' exists, do you want to overwrite it? (y/[n])? " CONTINUE
    if [[ $CONTINUE != "y" ]]; then
        exit 0
    fi
    git branch -D $NEWBRANCH
fi

if [[ -z $(git branch | grep dev) ]]; then
    TARGET=master
else
    TARGET=dev
fi

git fetch
git checkout -b $NEWBRANCH $TARGET
git merge $BRANCH
git reset --soft $TARGET
git commit

git push --force --set-upstream origin $NEWBRANCH

git checkout $BRANCH

sqrb.sh

#!/bin/bash
set -e

if [[ $# -eq 0 ]]; then
    BRANCH=$(git rev-parse --abbrev-ref HEAD)
elif [[ "$1" == "-h" || "$1" == "--help" ]]; then
    echo "Usage: `basename $0` [branch] [target]"
    exit 0
else
    BRANCH=$1
fi

if [[ $# -lt 2 ]]; then
    if [[ -z $(git branch | grep dev) ]]; then
        TARGET=master
    else
        TARGET=dev
    fi

    read -p "Do you want to squash '$BRANCH' and rebase it to '$TARGET'? (y/[n])? " CONTINUE
    if [[ $CONTINUE != "y" ]]; then
        exit 0
    fi
else
    TARGET=$2
fi

TEMPORARY="$BRANCH-squashed"

git fetch

git checkout $BRANCH
git diff $TARGET..HEAD > /tmp/1.diff

git checkout $TARGET
git checkout -b $TEMPORARY
git merge $BRANCH
git reset --soft $TARGET
git commit

git diff $TARGET..HEAD > /tmp/2.diff

if [[ $(diff /tmp/1.diff /tmp/2.diff) ]]; then
    git branch -D $TEMPORARY
    exit 1
else
    rm -f /tmp/1.diff /tmp/2.diff
fi

git push origin $TEMPORARY:$BRANCH --force

git checkout $BRANCH
git branch -D $TEMPORARY
git fetch --all
git reset --hard origin/$BRANCH