CSCI 3294 (Unix Power Tools), Fall 2009:
Homework 3

Credit:

20 points.

Reading

Read about the following topics in the list of suggested readings, either in one of the suggested readings or in another book or reference. (This is the topic for September 23):

• Shell scripting basics.

Programming Problems

Do the following programming problems. You will end up with at least one code file per problem. Turn in your code by sending mail to bmassing@cs.trinity.edu, with each of your code files as an attachment. Please use a subject line that mentions the course number and the assignment (e.g., ``csci 3294 homework 3''). If there's any question of which file(s) correspond to which problems, explain in the body of the mail message. You can develop your programs on any system that provides the needed functionality, but I will test them on one of the department's Fedora 11 Linux machines, so you should probably make sure they work in that environment before turning them in.

Shell scripting

1. (10 points) Do one of the following:
   1. Write a shell script that renames a file (specified as a parameter), changing any blanks in its name to underscores. If no filename is given, or if the file does not exist, the script should print an error message.

      Hint: See the examples in the class notes and the example scripts on the sample programs page.

   2. Write a shell script that makes use of a conditional (if/then/else/fi) and at least one positional parameter and does something you find useful or interesting. Include comments at the top of the script describing its purpose.

2. (10 points) Do one of the following:
   1. Write a shell script that searches all directories in your search path for a specified file/executable and prints the directories where it is found. For example, if the script is called find-in-path, find-in-path ls would print /bin or /bin/ls. If the specified file is found in more than one directory, the script should print them all. If it is not found at all, the script can print an error message or just do nothing. If no file/executable is specified, the script should print an error message.

      Hint: See the examples in the class notes and the example scripts on the sample programs page.

   2. Write a shell script that makes use of a loop (for or while) and does something you find useful or interesting. Include comments at the top of the script describing its purpose.