running_python_regex_from_bash.sh

#!/bin/bash

outversions="
Things 17.16 I am not 12.23.1 interested

36.35.17
35.34.16
24.23.5
19.18
3.
6.5
38.37.19

Things 17.16 I am not 12.23.1 interested

27.26.8
10.9
12.11
34.33.15
39.38.20
31.30.12
25.24.6
26.25.7
9.8
30.29.11
21.20.2
22.21.3
";

function matchwithpythonregex() {
# you cannot indent this!
pythonprogram="\
#!/usr/bin/env python
# -*- coding: UTF-8 -*-
import re;
import sys;
import codecs

# https://stackoverflow.com/questions/4020539/process-escape-sequences-in-a-string-in-python
ESCAPE_SEQUENCE_RE = re.compile(
r'''
( \\\\U........         # 8-digit hex escapes
| \\\\u....             # 4-digit hex escapes
| \\\\x..               # 2-digit hex escapes
| \\\\[0-7]{1,3}        # Octal escapes
| \\\\N\{[^}]+\}        # Unicode characters by name
| \\\\[\\\\'\"abfnrtv]  # Single-character escapes
)''', re.UNICODE | re.VERBOSE)

def decode_escapes(inputstring):
    def decode_match(match):
        return codecs.decode( match.group(0), 'unicode-escape' );
    return ESCAPE_SEQUENCE_RE.sub( decode_match, inputstring );

versions = ''.join( sys.argv[1:] );
versions = decode_escapes( versions );

# print( 'versions %s' % versions );
for line in versions.split( '\n' ):

    # print( 'line %s' % line );
    result = re.search( r'^((?:(?:\d)\.?)+)', line );

    if result:
        print( result.group( 1 ) );
";

    versions="${1}";
    python -c "${pythonprogram}" "${versions}";
}

resultlines="$(matchwithpythonregex "${outversions}")";
printf "The resultlines are:\\n%s\\n" "${resultlines}";