Replace an entire branch with new code, commit all and push it. Useful for generated github pages.

replace-branch.sh

#!/bin/bash

# Echo usage to console
usage() {
	cat << EOF
usage: replace-branch.sh [options] repo-url
options:
  -s
    The source folder (default: './build')
  -b
    The branch to deploy too (default: main)
  -o
    The temp output directory (default: '../deploy-{currenttime}')
  -y
	Continue without promoting for confirmation
EOF
	exit 1;
}

# Generic echo of a message as first param, second
function msg() {
	if [[ ! -z "$2" ]]
	then
		echo "$1" 1>&2; exit 1
	else
		echo $1
	fi
}

# the colon denotes that there has to be a value following the -flag, e.g. `-s ./dist, not that the flag is optional
# spacing is NOT important
# A case statement wont run if the option wasnt passed
while getopts s:b:o:yh option
do
	case "${option}" in
		s) SOURCEDIR=${OPTARG};;
		b) BRANCH=${OPTARG};;
		o) OUTPUTDIR=${OPTARG};;
		y) AUTOCONFIRM=1 && echo "hello";;
		h) usage;;
		:)
            msg "ERROR: Option -$OPTARG requires an argument" 1
            ;;
        \?)
            msg "ERROR: Invalid option -$OPTARG" 1
            ;;
	esac
done
shift $((OPTIND -1)) # This removes the params available so we can use positional params for the git repo "$1"

GITREPO=$1
[[ -z "$GITREPO" ]] && usage;

if [ -z "$BRANCH" ]; then BRANCH="main"; fi

# First ensure there is a value for outputdir, if not create generate one with a timestamp to avoid clashes
if [ -z "$OUTPUTDIR" ]; then OUTPUTDIR="$(readlink -f ../deploy-$(date +%s%N))"; else OUTPUTDIR="$(readlink -f $OUTPUTDIR)"; fi
# Check there isnt already an output directory as it will cause clashes
[ -d "$OUTPUTDIR" ] && msg "The '$OUTPUTDIR' already exists" 1;

# Ensure there is a source directory and it exists
if [ -z "$SOURCEDIR" ]; then SOURCEDIR="$(readlink -f './build')"; else SOURCEDIR="$(readlink -f $SOURCEDIR)"; fi
[ ! -d "$SOURCEDIR" ] && msg "The source directory '$SOURCEDIR' could not be found" 1;

ORIGINALDIR="$(pwd)"

## User message
echo "Git Repo: $GITREPO"
echo "Branch: $BRANCH"
echo "Source: $ORIGINALDIR"
echo "Temp Folder: $OUTPUTDIR"

# Get conformation from the user (a key press of 'y') to ensure they are happy to continue
[[ "$AUTOCONFIRM" -ne "1" ]] && read -p "Are you sure? " -n 1 -r

# Note as some have pointed out its better to 'not' negate this and exit as the code could still run if there is an error
if [[ "$AUTOCONFIRM" -eq "1" || $REPLY =~ ^[Yy]$ ]]
then
	# Create the output directory
	mkdir "$OUTPUTDIR"

	# Clone the lightest version of the repo possible into the current directory
	git clone --depth 1 $GITREPO "$OUTPUTDIR"

	# Switch to that directory
	cd "$OUTPUTDIR"

	# Delete all files from target folder, making sure to ignore the .git files and folder at top level only
	find . -maxdepth 1 ! -name '.git*' ! -name '.' -exec rm -rf {} \;

	cp -R "$SOURCEDIR/." "$OUTPUTDIR"

	git add .

	git commit -m "Published"

	git push

	cd "$ORIGINALDIR"

	rm -rf "$OUTPUTDIR"

	echo "Finished..."
fi