# Unix-specific services

The modules described in this chapter provide interfaces to features that are unique to the Unix operating system, or in some cases to some or many variants of it. Here’s an overview:

- `shlex` — Simple lexical analysis
  - shlex Objects
  - Parsing Rules
  - Improved Compatibility with Shells
- `posix` — The most common POSIX system calls
  - Large File Support
  - Notable Module Contents
- `pwd` — The password database
- `grp` — Baza danych grup
- `termios` — POSIX style tty control
  - Przykład
- `tty` — Terminal control functions
- `pty` — Pseudo-terminal utilities
  - Przykład
- `fcntl` — The `fcntl` and `ioctl` system calls
- `resource` — Resource usage information
  - Resource Limits
  - Resource Usage
- `syslog` — Unix syslog library routines
  - Przykłady
    - Simple example