# Argument passing format
Argument parsing can be done with short `-<chars...>` and/or long `--arg[{=, }<value>]` (with or without value, `=` optional.
Short arguments can be chained together: `-abc` is equal to `-a -b -c` . There can be multiple of these: `-ie -O` is equal to `-i -e -O` .
# **TODO** Long arguments
* **TODO** User-set sink file path (e.g `--path /path/to/sink` ) which overrides the default `/dev/null` .
* `--env <file>` - Read environment variables, line-by-line, from `<file>` in the format `KEY=value` and send that as the program's `envp` . Multiple of these can exist, they are concatenated.
(example usage: `LD_PRELOAD=malicious.so sink --env <(env | grep ^LD_PRELOAD) setuid-binary` )
* `--env=[<key>=<value>]` - Add (or replace) `<key>=<value>` to/in `envp` . Multiple of these can exist.
(example usage: `sink --env=LD_PRELOAD=replace.so binary` )
# Short Arguments
* `-i` Replace `stdin` (**default**)
* `-o` Replace `stdout` (**default**)
* `-e` Replace `stderr` (*default with feature* `REPLACE_STDERR` )
* `-I` No replace `stdin`
* `-O` No replace `stderr`
* `-E` No replace `stderr` (**default** *without feature* `REPLACE_STDERR` )
* `-p` `envp` passthrough, including optional modifications. (see `--env` .) (**default** *without feature* `NO_ENV` )
* `-P` No `envp` passthrough, **except** optional modifications. (see `--env` .) (*default with feature* `NO_ENV` )
# **TODO** Other options
* **TODO** Specific fd passthrough (*probably long arg, could also possibly be short args for std{in,out,err} streams specifically*)
* **TOTO** CLOEXEC control (*short arg*)
* **TOTO** add specific fds / open specific files (optionally also at specific fds) to passthrough (*probably long arg*)
# Examples
Short args:
```shell
$ sink -ioe cat # sink steam in,out,err
$ sink -iOE cat # sink stream in. keep stream out and err
$ sink -O cat # sink default streams, but keep out
$ sink -E cat # sink default streams and err
```
**TODO** Long args:
## Redundant examples
Short args:
```shell
$ sink -iI cat # sink default streams and in (I comes after the redundant i)
$ sink -Ii cat # sink default streams except in (i comes after the redundant I)
```
**TODO** Long args:
