Shell Programming and Scripting

nawk -v RS='' '/Banana/ {print $0 ORS}' myFile

# FindR - Find(e)r - Find( )R(ecords)
# Finds certain records within decoded files given one or more search patterns...
# v3.0 - 20100317 - cs03dmj

# Usage Information:
usage() {
        echo "Usage: $0 decoded_filname search_pattern(s)"
        echo && echo "e.g. to find records containing a value:"
        echo "  $0 myfile monkey"
        echo && echo "e.g. to find records containing several values:"
        echo "  $0 myfile monkey banana"
        echo && echo "e.g. to find records containing specific data, use one or more regular expressions in quotes:"
        echo "  $0 mydecodedfile \"m.*y\" \"b.*a\""
        echo && echo "N.B. If output is redirected to a file, user messages will not be included..." && echo
        # Exit with an errored return code:
        exit 1
}

# If the number of parameters ($#) is less than two (i.e. filename and one search pattern) then display usage information:
[ $# -lt 2 ] && usage

# If the first paramater ($1) is not a valid file, report the problem then display usage information:
[ ! -f $1 ] && echo "File $1 does not exist." && usage

# Use nawk as awk can't handle large files:
nawk '
BEGIN {
        # Records are split by one or more blank lines, so set the Record Separator (RS) appropriately:
        RS = ""
        # ARGV is the built-in array of passed parameters.
        # ARGC is the number of elements in array ARGV
        # ARGV[0] = nawk
        # ARGV[1] = decoded_filename
        # Parse remaining parameters (ARGV[2 ...]) into "searches" array:
        for (i = 2; i < ARGC; i++) {
                searches[i] = ARGV[i]
                # Delete the parameter so is not treated as another input file:
                delete ARGV[i]
        }
        # Create a variable to count the total number of matches (if any):
        totalmatches = 0
}

# For every record:
{
        # For every search pattern in "searches" array:
        for (search in searches) {
                # If the record does not contain a matching search, skip to the next record:
                if ( $0 !~ searches[search] ) { next }
        }
        # If we have made it this far, all searches have been matched, so print the record followed by a newline:
        print $0 "\n"
        # Increment the total matches variable:
        totalmatches++
}

# At the end of the file:
END {
        # Notify the user (via stderr) how many matches have been found:
        print "...found " totalmatches " matching record(s) from " NR " total record(s)." > "/dev/stderr/"
}
' "$@" # <-- Here's where we pass all the parameters to nawk for processing, using $@ in quotes to ensure that whitespaces are kept and wildcards are not expanded by the shell.