wrappers/su at main · tanazd2-dev/wrappers · GitHub

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#!/usr/bin/env sh

VERSION="su 5.3.0"

show_help() {
cat <<'HELP'
Usage: su [options]

Options:
  -c, --command CMD          run command via shell
  -s SHELL                  use specified shell
  -, -l, --login            login shell
  -m, -p, --preserve-environment
                            preserve environment variables
  -h, --help                show help
  -V, --version             show version
HELP
}

# ----------------------------
# Shell auto-detection
# ----------------------------
if [ -x "/usr/bin/bash" ]; then
  shell="/usr/bin/bash"
elif [ -x "/bin/bash" ]; then
  shell="/bin/bash"
elif [ -n "$PREFIX" ] && [ -x "$PREFIX/bin/bash" ]; then
  shell="$PREFIX/bin/bash"
else
  shell="/bin/sh"
fi

cmd=""
login=0
preserve_env=0

# ----------------------------
# Argument parsing
# ----------------------------
while [ $# -gt 0 ]; do
  case "$1" in

    -h|--help)
      show_help
      exit 0
      ;;

    -V|--version)
      echo "$VERSION"
      exit 0
      ;;

    -c|--command)
      shift
      cmd="$1"
      shift
      ;;

    -s)
      shift
      shell="$1"
      shift
      ;;

    -l|--login|-)
      login=1
      shift
      ;;

    -m|-p|--preserve-environment)
      preserve_env=1
      shift
      ;;

    *)
      shift
      ;;
  esac
done

# ----------------------------
# Login shell
# ----------------------------
if [ "$login" -eq 1 ]; then
  shell="$shell -l"
fi

# ----------------------------
# Execution logic
# ----------------------------
if [ "$preserve_env" -eq 0 ]; then
  env -i PATH="$PATH" HOME="$HOME" "$shell" -c "${cmd:-exec $shell}"
else
  if [ -n "$cmd" ]; then
    exec $shell -c "$cmd"
  else
    exec $shell
  fi
fi

exec $shell