sharexec - create a shar that also runs a specific executable bundled in the shar

sharexec

#!/usr/bin/env bash
# USAGE: sharexec [-d <dir>] <executable> <file>... > my.sh
# Creates a shar file containing <executable> + all <file>s
# On execution:
# 1. unpack everything in <dir> (default: temp dir)
# 2. run <executable>
# 3. if temp dir used, remove it

warn() {
  echo "WARNING: $*" >&2
}
err() {
  echo "ERROR: $*" >&2
}
fatal() {
  echo "FATAL ERROR: $*" >&2
  exit 1
}
dir=
while true; do
  case "$1" in
    -d) dir=$2; shift;;
    *) break;;
  esac
  shift
done

# the shar generator
echo '#!/usr/bin/env bash'
declare -f warn err fatal
declare -p dir
cat <<EOS
if [[ -z \$dir ]]; then
  dir=\$(mktemp -d /tmp/sharexec.XXXXXX) || fatal "Unable to create temp dir"
  trap 'rm -fr "\$dir"' EXIT
fi
mkdir -p "\$dir" || fatal "Unable to create dir '\$dir'"
cd "\$dir" || fatal "Unable to cd into '\$dir'"
EOS
for i in "$@"; do
  if [[ -r $i ]]; then
    cat <<EOS
base64 -d >"$(basename "$i")" <<'EOF' || fatal "Unable to decode '$i'"
$(base64 < "$i")
EOF
EOS
    [[ -s $bin ]] || bin=$(basename "$i")
  else
    warn "Unable to read '$i', skipping"
  fi
done
cat <<EOS
chmod +rx "$bin"
./"$bin"
EOS