On Unix system type files can be identified with the ls -l command which displays the type of the file in the first alphabetic letter of the file system permissions field. You can find more information about file type on Unix system on the [wikipedia page](https://en.wikipedia.org/wiki/Unix_file_types).

- '-' A regular file ==> `file`.
- 'd' A directory ==> `directory`.
- 'l' A symbolic link ==> `symlink`.
- 'c' A character special file. It refers to a device that handles data as a stream of bytes (e.g: a terminal/modem) ==> `character_file`.
- 'b' A block special file. It refers to a device that handles data in blocks (e.g: such as a hard drive or CD-ROM drive) ==> `block_file`.
- 'p' a named pipe ==> `pipe`.
- 's' a socket ==> `socket`.
- 'D' a door ==> `door`.

In this kata you should complete a function that return the `filetype` as a string regarding the `file_attribute` given by the `ls -l` command. 

For example if the function receive `-rwxr-xr-x` it should return `file`.

```python

USER_FILENAME = "<user_code>"
import sys, json, builtins
import math, heapq, bisect, itertools, functools, collections, statistics, fractions, decimal, operator, array, random, re, string, os, pathlib
try:
    import resource as _res
except Exception:
    _res = None
from collections import Counter, defaultdict, deque, OrderedDict
from functools import lru_cache, reduce
from itertools import accumulate, permutations, combinations, product
from math import gcd, ceil, floor, sqrt
from decimal import Decimal
try:
    from typing import *
except Exception:
    pass
try:
    sys.setrecursionlimit(1_000_000)
except Exception:
    pass
try:
    import site as _site
    try:
        _sys_sites = _site.getsitepackages() if hasattr(_site, "getsitepackages") else []
        for _p in _sys_sites:
            if _p and _p not in sys.path:
                sys.path.append(_p)
    except Exception:
        pass
    try:
        _usp = _site.getusersitepackages()
        if isinstance(_usp, str):
            _usp = [_usp]
        for _p in _usp:
            if _p and _p not in sys.path:
                sys.path.append(_p)
    except Exception:
        pass
except Exception:
    pass

def _disabled_input(*args, **kwargs):
    raise RuntimeError("input() is disabled in callable mode")
builtins.input = _disabled_input

ns = {"__name__": "__judge__"}  # prevent if __name__ == "__main__" blocks
for _k, _v in list(globals().items()):
    if not _k.startswith("_"):
        ns[_k] = _v
_CODE = "def linux_type(file_attribute):\n    types = {'-': 'file',\n             'd': 'directory',\n             'l': 'symlink',\n             'c': 'character_file',\n             'b': 'block_file',\n             'p': 'pipe',\n             's': 'socket',\n             'D': 'door'}\n    if not file_attribute:\n        return None\n    ty = file_attribute[0]\n    if ty in types:\n        return types[ty]\n    else:\n        return None"
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

_target = None
_fn_name = 'linux_type'
if _fn_name:
    if "Solution" in ns:
        try:
            _obj = ns["Solution"]()
            if hasattr(_obj, _fn_name):
                _target = getattr(_obj, _fn_name)
        except Exception:
            _target = None
    if _target is None and _fn_name in ns and callable(ns[_fn_name]):
        _target = ns[_fn_name]
# Fallback: if there's exactly one user-defined function, use it
if _target is None:
    _cands = [v for k, v in ns.items() if callable(v) and getattr(v, "__module__", "") in ("__judge__", "__main__")]
    _user_funcs = [c for c in _cands if getattr(c, "__name__", "").startswith("_") is False]
    if len(_user_funcs) == 1:
        _target = _user_funcs[0]
if _target is None:
    raise RuntimeError(f"Could not resolve callable '{_fn_name}'")

_raw = sys.stdin.read().strip()
if _raw:
    _parsed = json.loads(_raw)
    if isinstance(_parsed, dict):
        _kwargs = _parsed.get("kwargs", {})
        _args = _parsed.get("args", [])
    else:
        _args, _kwargs = _parsed, {}
else:
    _args, _kwargs = [], {}
if not isinstance(_args, (list, tuple)):
    _args = [_args]
_res = _target(*_args, **_kwargs)
try:
    sys.stdout.write(repr(_res) + "\n")
except Exception:
    pass

```

Measured memory_bytes: 5400