tech stuff.

Debugging regex from the CLI

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Just stumbled across this obvious solution from the why didn’t I realize this earlier? department. GNU grep makes an great regex debugger!

The secret is combining -P (for perlre) with --color to color the matched pattern. For example:

% echo -e '123\n123.123' | grep -P '^\d+(?!\.\d)'
123
123.123
% echo -e '123\n123.123' | grep -P '^\d+(?![\.\d])'
123
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Written by Lee Verberne

2017/02/21 at 12:43

Posted in Uncategorized

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