searchWord.py

#!/usr/bin/python
import argparse
import re

''' A utility to search for a word in a text file. If found, returns the
complete paragraph the word was found in.

Useful in conjunction with gpg to use as a command line password manager
using a simple text file.
'''


def filesearch(pattern):
    '''
    Search each line of the file and return a list of line numbers 
    that match the pattern. There could be multiple returns.
    '''
    linecount = 0
    founditems = []
    for line in lines:
        line = line.strip()
        if p.search(line):
            founditems.append(linecount)
        linecount = linecount + 1
    return founditems

def findstartpositions(founditems):
    '''
    Determine start positions by taking line number (item), subtract 1 and test
    for a blank line.
    '''
    startpositions = []
    for item in founditems:
        while lines[item] not in ['\n', '\r\n']:
            item = item - 1
        startpositions.append(item + 1)
    return startpositions

def makeunique(seq):
    '''
    Sometimes the search word is repeated within the paragraph, so make the
    paragraphs that we print unique.
    '''
    return set(seq)

def printparagraph(startpositions):
    '''
    Print starting with startposition (a line number) and continue
    until a blank line is encountered. If EOF is encountered, break.
    '''
    for start in startpositions:
        while lines[start] not in ['\n', '\r\n']:
            print(lines[start].strip())
            start = start + 1
            if lines[start] == lines[-1]:
                break
        print('\n')
    return

parser = argparse.ArgumentParser(description="search for a word and display the surrounding paragraph")
parser.add_argument("pattern", help="the word you wish to match")
parser.add_argument("--input", type = argparse.FileType("r"), default = "-",
                    dest = "infile", help = "the file you wish to search,\
                    defaults to stdin")
args = parser.parse_args()

''' Read each line of the file into a list '''
lines = args.infile.readlines()

''' Compile a regular expression search pattern, case insensitive '''
p = re.compile(args.pattern, re.I | re.M)

founditems = filesearch(p)

startpositions = findstartpositions(founditems)

printparagraph(makeunique(startpositions))

args.infile.close()