more robust: "hostname" command might be absent, notably on Arch Linux (and other systemd-based distributions);
#!/usr/bin/env bash
#
# Author: Makarius
#
# DESCRIPTION: raw ML process (interactive mode)
isabelle scala_build || exit $?
eval "declare -a JAVA_ARGS=($ISABELLE_TOOL_JAVA_OPTIONS)"
mkdir -p "$ISABELLE_TMP_PREFIX" || exit $?
if type -p "$ISABELLE_LINE_EDITOR" > /dev/null
then
exec "$ISABELLE_LINE_EDITOR" isabelle java "${JAVA_ARGS[@]}" isabelle.ML_Console "$@"
else
echo >&2 "### No line editor: \"$ISABELLE_LINE_EDITOR\""
exec isabelle java "${JAVA_ARGS[@]}" isabelle.ML_Console "$@"
fi