+if command -v gsed >/dev/null
+then
+ SED=gsed
+elif sed --help >/dev/null 2>&1
+then
+ SED=sed
+else
+ printf 'ERROR: GNU sed is missing\n' >&2
+ exit 1
+fi
+
+printRealPath ()
+{
+ if command -v grealpath >/dev/null
+ then
+ grealpath "${1}"
+ elif command -v realpath >/dev/null
+ then
+ realpath "${1}"
+ elif command -v greadlink >/dev/null
+ then
+ # test greadlink first as greadlink has the feature on macos
+ # but readlink only has it on linux, note that it's probably
+ # the same on bsd
+ # note: (g)readlink requires the file to be create first
+ greadlink -f "${1}"
+ elif command -v readlink >/dev/null
+ then
+ # --help and -f options are GNU readlink things
+ if readlink --help >/dev/null 2>&1
+ then
+ readlink -f "${1}"
+ else
+ if ! python -c "import os; print(os.path.realpath('${1}'))"
+ then
+ printf 'ERROR: GNU realpath or other way to compute real path of a file is missing\n' >&2
+ exit 1
+ fi
+ fi
+ fi
+}
+