(Not too successfully) trying to use Unix tools instead of Python utility scripts

Inspired by articles such asWhy you should learn just a little Awk andLearn one sed command, I am trying to make use of Unix toolssed, awk, grep, cut, uniq, sort, etc. instead of writing short Python utility scripts.

Here is a Python script I wrote this week. It greps a file for a given regular expression pattern and returns a unique, sorted, list of matches inside the capturing parentheses.

# grep2.py

import re
import sys


def main():
    patt = sys.argv[1]
    filename = sys.argv[2]

    text = open(filename).read()
    matchlist = set(m.group(1) for m in re.finditer(patt, text, re.MULTILINE))
    for m in sorted(matchlist):
        print m


if __name__ == '__main__':
    main()

As an example, I used my script to search one of the Django admin template files for all the Django template markup in the file.

$ python grep2.py '({{[^{}]+}}|{%[^{}]+%})' tabular.html 

Output:

{% admin_media_prefix %}
{% blocktrans with inline_admin_formset.opts.verbose_name|title as verbose_name %}
{% cycle "row1" "row2" %}
{% else %}
{% endblocktrans %}
{% endfor %}
{% endif %}
{% endspaceless %}
{% for field in inline_admin_formset.fields %}
{% for field in line %}
{% for fieldset in inline_admin_form %}
{% for inline_admin_form in inline_admin_formset %}
{% for line in fieldset %}
{% if field.is_hidden %}
{% if field.is_readonly %}
{% if field.required %}
{% if forloop.first %}
{% if forloop.last %}
{% if inline_admin_form.form.non_field_errors %}
{% if inline_admin_form.has_auto_field %}
{% if inline_admin_form.original %}
{% if inline_admin_form.original or inline_admin_form.show_url %}
{% if inline_admin_form.show_url %}
{% if inline_admin_formset.formset.can_delete %}
{% if not field.widget.is_hidden %}
{% if not forloop.last %}
{% load i18n adminmedia admin_modify %}
{% spaceless %}
{% trans "Delete?" %}
{% trans "Remove" %}
{% trans "View on site" %}
{{ field.contents }}
{{ field.field }}
{{ field.field.errors.as_ul }}
{{ field.field.name }}
{{ field.label|capfirst }}
{{ forloop.counter0 }}
{{ inline_admin_form.deletion_field.field }}
{{ inline_admin_form.fk_field.field }}
{{ inline_admin_form.form.non_field_errors }}
{{ inline_admin_form.original }}
{{ inline_admin_form.original.id }}
{{ inline_admin_form.original_content_type_id }}
{{ inline_admin_form.pk_field.field }}
{{ inline_admin_formset.formset.management_form }}
{{ inline_admin_formset.formset.non_form_errors }}
{{ inline_admin_formset.formset.prefix }}
{{ inline_admin_formset.opts.verbose_name_plural|capfirst }}
{{ inline_admin_form|cell_count }}
{{ verbose_name }}

Here's my attempt at using Unix tools:

$ sed -rn 's/^.*(\{\{.*\}\}|\{%.*%\}).*$/\1/gp' tabular.html | sort | uniq 

However the output isn't quite the same:

{% admin_media_prefix %}
{% else %}
{% endblocktrans %}
{% endfor %}
{% endif %}
{% endspaceless %}
{% for field in inline_admin_formset.fields %}
{% for field in line %}
{% for fieldset in inline_admin_form %}
{% for inline_admin_form in inline_admin_formset %}
{% for line in fieldset %}
{% if field.is_readonly %}
{% if inline_admin_form.form.non_field_errors %}
{% if inline_admin_form.original or inline_admin_form.show_url %}
{% if inline_admin_formset.formset.can_delete %}
{% if not field.widget.is_hidden %}
{% load i18n adminmedia admin_modify %}
{% spaceless %}
{% trans "Remove" %}
{{ field.contents }}
{{ field.field }}
{{ field.field.errors.as_ul }}
{{ field.field.name }}
{{ field.label|capfirst }}
{{ inline_admin_form.fk_field.field }}
{{ inline_admin_form.form.non_field_errors }}
{{ inline_admin_formset.formset.management_form }}
{{ inline_admin_formset.formset.non_form_errors }}
{{ inline_admin_formset.formset.prefix }}
{{ inline_admin_formset.opts.verbose_name_plural|capfirst }}

Unix tools are powerful and concise, but I still need to get a lot more comfortable with their syntax. Please leave a comment if you know how to fix my command.