alias-exec

#!/bin/sh -e

# Multitool binary provider. Default is 'busybox'.
[ -n "$ALIAS_PROVIDER" ] ||
	ALIAS_PROVIDER='busybox'

# See executed script REQUIRES variable. Default is most common tools.
[ -n "$ALIAS_REQUIRES" ] ||
	ALIAS_REQUIRES="$REQUIRES \
printf id mkdir rmdir ln cp mv rm readlink \
chown chmod cmp mktemp sort tr sed \
"

################################################################################

if [ -z "$THIS_DIR" ]; then
	# This script file name (on most shells)
	THIS_SCRIPT="$0"

	# Program (script) name
	prog_name="${THIS_SCRIPT##*/}"

	# Try to determine THIS_DIR unless given
	THIS_DIR="${THIS_SCRIPT%$prog_name}"
	THIS_DIR="${THIS_DIR:-.}"
	# Make it absolute path
	THIS_DIR="$(cd "$THIS_DIR" && echo "$PWD")"
fi

if ! type "$ALIAS_PROVIDER" >/dev/null 2>&1; then
	echo "$prog_name: multitool binary provider \"$ALIAS_PROVIDER\" not found" >&2
	exit 1
fi

# Setup aliases
for r in $ALIAS_REQUIRES; do
	eval "$r() { '$ALIAS_PROVIDER' '$r' \"\$@\"; }"
done

# Setup helper to execute single alias (never export it)
do_alias_func()
{
	"$IN_ALIAS_EXEC" "$@"
}
DO_ALIAS_EXEC='do_alias_func'

if [ -n "$IN_ALIAS_EXEC" ]; then
	# Only aliases is necessary here
	return 0
fi

# Command to run
if [ $# -le 0 ]; then
	echo "Usage: $THIS_SCRIPT {deploy.sh|install.sh|...} <args>..." >&2
	exit 2
fi

cmd="$1"
[ -z "${cmd##*/*}" ] || cmd="$THIS_DIR/$cmd"
shift

# Always export it to indicate that aliases must be sourced by executed script
export IN_ALIAS_EXEC="$ALIAS_PROVIDER"

# Source rather than exec as we need to submit aliases
. "$cmd" "$@"