# ipgrep

Extract IP addresses (and MAC addresses) from text, with optional reachability checks, reverse DNS, and ipinfo.io lookups.

## Build

```sh
./scripts/build.sh
./dist/ipgrep --help
```

## Install (local)

```sh
./scripts/build.sh
sudo install -m 0755 ./dist/ipgrep /usr/local/bin/ipgrep
```

## Usage

```sh
# Extract IPv4 addresses from stdin
cat file.txt | ipgrep

# Extract and uniq/sort
ipgrep -u -s file.txt

# Extract MAC addresses
ipgrep -m file.txt

# Reachability filter (auto chooses ICMP if permitted, otherwise TCP probe)
ipgrep -p file.txt

# Reverse DNS (IP only)
ipgrep -r file.txt

# Lookup ipinfo.io and output CSV (default header included)
ipgrep -l --format=csv file.txt
```

## Notes

- `-p/--pingable`:
  - `--ping-mode=auto` (default) uses ICMP echo when raw sockets are available, otherwise falls back to a TCP connect probe.
  - ICMP echo typically requires root or `cap_net_raw` on Linux:
    - `sudo setcap cap_net_raw+ep /path/to/ipgrep`
- `-l/--lookup` cache:
  - defaults to the OS cache dir (override with `--cache-path`)
  - control size and freshness with `--cache-max-entries` and `--cache-ttl`
- MAC `-r/--resolve` and MAC `-p/--pingable` are best-effort and rely on the local neighbor/ARP table:
  - Linux: `/proc/net/arp`
  - Other OSes: currently unsupported without external tooling
