Practice Using Pipes

Here is a list of small tasks that can be done by chaining together 2 or more unix standard commands into a pipeline to get the results. First one to e-mail me a correct and complete solution for a particular task will receive fame and glory for their brillant solution, and maybe a few bonus points...

1. The ps command can be used to get a list of processes running on the system. Create a pipeline to find all of the processes that you are running on the system.

2. The tail command can be used to continuously monitor the output being generated to a file. Write a filter to watch a file continuously and monitor it for when certain events or output is generated. For example, the /var/log/messages file is where lots of unix services dump log messages. Monitor this file and look for when new kernel messages are generated.

3. du can be used to determine the amount of disk usage being used by a directory. Determine which directory is using the most disk space (hint du and sort would be useful here).

4. Print out only the name and modification time of the oldest file in the current directory. Do the same but for the 3 oldest files.

5. Find is a powerful command that can be used to find files based on not only the name of the file matching a pattern, but by modification time, owner, etc. Find all of the directories under the current directory, but filter out all of the “.svn” subversion directories from the list of directories.