grep2awk: ZSH plugin for command transformation

While trying to find the needle in a haystack, you find yourself recklessly grepping some log files. Suddenly, it occurs to you that there might be a pattern in the data, and awk will be the fastest way to figure out if this pattern has any relevance or not. You want to change your grep into an awk oneliner.

This involves some mechanical work: Arrow up to get to the command line, move to the word grep and change it, forward to the start of the regular expression and add '/. Move to the end of the regular expression, and type: / {}'. Not a big deal, but mechanical work, which does add up if you're doing this eight times a day.

For this slight inconvenience, the tool grep2awk was written. It finds the first occurrence of the word grep in the current command line, and tries to convert the options and the regular expression into a skeleton for an awk-script. Just press a key you have chosen yourself, and you're already past the point of potential distraction which the mechanical work can entail.

Some examples

After pressing a magical key combination, your editing buffer will be searched for grep commands, and the buffer will have the grep part replaced by an awk command.

% grep 'there^here'<CTRL-X><CTRL-A>
% awk -- '/there\^here/ {print $0}'

It works with pipes, subshells, et cetera (thanks to split-shell-arguments):

% ps aux | grep kswap | sort<CTRLX><CTRL-A>
% ps aux | awk -- '/kswap/ {print $0}' | sort

The meat of this thing is in the transformation of BREs to EREs (when egrep or -E is not called):

% grep '^a^b\(c(\|d)e\)' file<CTRL-X><CTRL-A>
% awk -- '/^a\^b(c\(|d\)e)/ {print $0}' file

Some options to grep will be translated to appropriate awk statements:

% grep -vi 'not here' file <CTRLX><CTRL-A>
% awk -- 'BEGIN{IGNORECASE=1}; !/not here/ {print $0}' file

Installation

If you are using some zsh configuration framework or plugin manager, jump ahead. If you are rolling your own zsh configuration, here is the deal. Clone the repository someplace:

cd someplace
git clone [email protected]:joepvd/grep2awk.git

Then, in ~/.zshrc, append someplace to $fpath:

fpath+=(someplace)

Make sure grep2awk gets autoload-ed, making the script known as a line editor (zle) script, and assigning a key binding to it:

autoload -Uz grep2awk
zle -N grep2awk
bindkey "^X^A" grep2awk

Now, pressing <CTRL-X>-<CTRL-A> will bring you goodies!

Oh-my-zsh

Clone this repository in the custom/plugins directory of oh-my-zsh. Then add grep2awk to the list of plugins:

plugins+=(grep2awk)

If you don't like the default ^X^A-keybinding, you can set the variable GREP2AWK_KEY to your desired key combination.

Antigen

Put antigen bundle joepvd/grep2awk in your startup file, and you should be good. GREP2AWK_KEY can be used to override the default key binding.

Prezto

Clone the repository in the modules directory of zpresto:

cd ${ZDOTDIR:-$HOME}/.zprezto/modules
git clone [email protected]:joepvd/grep2awk.git

Then, probably in ~/.zprestorc, add grep2awk to the list zstyle ':prezto:load' pmodule. The keybinding defaults to ^X^A, but can be set by setting the variable GREP2AWK_KEY.

Configuration

This zle function can be configured as follows:

zstyle ':grep2awk:' awk 'gawk --'

This sets the command that will be executed. The default is awk, and if you desire to use another awk program, you can do so.

zstyle ':grep2awk:*:' debug /path/to/file

If debug has a value, some information is dumped in the file specified. If it does not start with a /, the working directory of the current zsh shell is used. Currently, only the context bre2ere is supported.

The following grep options are supported:

-v

inverse match

-w

word match

-x

line match

-l

list matching files

-L

list not matching files

-H

include filename in result

-n

include line number in result

-c

count occurrences per file

-i

case insensitive matching

-E

Extended Regular Expressions

-F

Fixed string matching

Development

Patches and bug reports welcome! Main development takes place at https://github.com/joepvd/grep2awk/.

There is a testing library in the t-directory, in which the testing framework from the ZSH-project has been adjusted to work with the currently installed shell. Please run and update the tests when playing with the code.

Please let me know if you like it, and what could be better to support your needs!