extract

Extract text from text using a regex - a simple way to consume keyed fields from poorly-(or un-)structured text.

Usage

Extract accepts as an argument a regex with a single capture group, and will read lines from stdin, printing captured values.

> echo "hello subject=world" | extract "subject=(.+)"
world

extract keeps reading until it reaches the end of input, processing lines one-at-a-time:

> cat multiline
Hello subject=world
Hello subject=Dorris
> cat multiline | extract "subject=(\w+)"
world
Dorris

Installation

From source:

cargo install

From crates.io:

cargo install extract

License

MIT / Apache 2.

Issues / Contributing

Feel free to open an issue / PR. I’d be interested in adding support for more structured outputs (e.g. JSON from a regex with named capture groups).

FAQs

• How is this different to grep -o?

extract only prints the captured group, not the whole match.

• Can’t you use sed for this?

Not first time, normally. Maybe your sed-fu is better than mine. This tool was originally created when I needed to extract ids from the output of xinput --list, in frustration after the fourth attempt to deliver the correct incantations to sed.