Copies and shortens code from one file to another

codecopy.py

import argparse


def cp(inp, out):

    with open(out, "w") as output, open(inp, "r") as inp:
        lines = []
        for line in inp:
            # ignores new lines
            if line == "\n":
                continue
            # gets the first word
            sentenceList = line.split(" ", 1)
            firstWord = sentenceList[0]
            
            # shortens the first word if it's longer than 4
            if len(firstWord) > 4:
                firstWord = firstWord[0]
                
            # replaces the shortened word  
            lines.append(firstWord+" "+" ".join(sentenceList[1:]))

        output.writelines(lines)


def main():
    parser = argparse.ArgumentParser(description="Copies and shortens lines"
                                     " between 2 files.")

    parser.add_argument("inputFile", metavar="inputFile", help="Input file")
    parser.add_argument("outputFile", metavar="outputFile", help="Output file")

    args = parser.parse_args()

    cp(args.inputFile, args.outputFile)
    print("Copied from "+str(args.inputFile) + " to " + args.outputFile + ".")
    

if __name__ == "__main__":
    main()