Grab — a unix filter for extracting tokens

Grabs specified tokens from lines on stdin.

usage: grab.py [-h] command [projection]

Each character in command specifies a token. grab will scan the input line for each token in command and print them tab-separated.

If projection is specified, only these tokens are printed (0-indexed). Indices are numbers from 0–9.

Installation

$ pip install futils-grab

Examples

• grab first two numbers from each line: grab dd
• grab "-quoted string and number: grab Qd
• grab three numbers, print them in reverse order: grab ddd 210
• grab client and http status from apache log: <access.log grab iqd 02

Known token types

• d (integer)
• i (IPv4 address)
• a Address (hostname or IP)
• e (email address)
• q (single-quoted string)
• Q (double-quoted string)
• w (word)
• [ (square-bracketed text)

Override or define new token types

You can define your own token types in ~/.grabrc, as a JSON object that maps token type (single character) to Python Regex.

$ cat ~/.grabrc
{
    "b": "foo.?"
}