Using bash

Here is a small bash script. It changes file suffixes:

    #! /bin/bash

    old_suffix=$1
    new_suffix=$2

    for f in *.$old_suffix
    do
        new_name=${f%.*}.$new_suffix
        echo Rename $f to $new_name
    done

You might use it like this, to rename all of your C files (ending in .c) to be C++ files (ending in .cpp):

    ./rn c cpp

For this lab, you should:

Understand how the script works
Understand why we said ./rn as opposed to just rn
Copy & paste this into your own file rn, and try it out
Make it actually rename the file, rather than just saying so
Add a usage message if too many or too few arguments are given
Send the usage message to stderr
Complain if a file can’t be renamed
Not clobber existing files

For extra fame & glory, you could:

Add a -n option that doesn’t rename, but just says what it would do
Add a -v option that renames verbosely
Complain if no files have the given suffix
Make it work for filenames and suffixes that contain spaces
Make it work for suffixes that are wildcards (whatever that means)

CS253: Software Development with C++

Spring 2018

Bash

Using bash