How to find the value for a given key, in a particular file. The notion of "key" and "value" are a bit loose. See the documentation.

findValueForKeyInFile.sh

#!/bin/bash

# In this example, we demonstrate how to find the value for a given key, in a particular file,
# using the Bash Shell Scripting language. We've setup some primitive functions to provide
# some modularity. See near the end for example usage on how you might call this.
#
# Assumptions:
# 1. Stripping leading and trailing whitespace in the value string is desired.
# 2. The last occurrence of the key (if there are multiple) is all we care about.


# This function strips out leading and trailing whitespace.
# It is adapted from the excellent examples found at: http://stackoverflow.com/a/3232433/535054
# Make sure you encase the value to be stripped in double quotes at the call site, incase
# you have a phrase whose intermediate spaces you do not wish to be stripped.
#
# @param $1 The string whose leading and trailing spaces you wish to be stripped.
#
# @return The stripped version of the passed in string.
strip_external_whitespace() {
    # Retrieve parameters:
	local string_to_strip=$1
	
	stripped_version="$(echo -e "${string_to_strip}" | sed -e 's/^[[:space:]]*//' -e 's/[[:space:]]*$//')"
	echo ${stripped_version}
}


# Finds a value associated with a specified key, in the specified file. This function
# assumes that there is only once instance of the string to be found.
#
# @param $1 The path and name to the file we'll search within.
# @param $2 The string representing the "key" we are searching for.
# @param $3 The string representing the delimiter between the key and the value.
#
# @return The value associated with the specified key, stripped of leading and trailing whitespace.
find_value_for_key_in_file() {
    # Retrieve parameters:
	local file_path=$1
	local provided_key=$2
    local provided_delimiter=$3
	
	retrieved_value_raw=`egrep "${provided_key}" ${file_path} | tail -1 | cut -f 2 -d ${provided_delimiter}`
	retrieved_value=`strip_external_whitespace "${retrieved_value_raw}"`
	
	echo ${retrieved_value}
}


# --- Example Usage ---
#
# Let's say you have a text file on disk with the line:
#
# 	Build Configuration: Debug Level 1
#
# You want to treat the word 'Build Configuration' as a key, the colon as a delimeter,
# and you thus, want to retrieve the value string 'Debug Level 1'. 

file_path=~/MyTestFile.txt
provided_key="Build Configuration"
provided_delimiter=":"

echo `find_value_for_key_in_file "${file_path}" "${provided_key}" "${provided_delimiter}"`