Write exercises for using basic shell tools

[illicitonion]

We want backlog items for using:

• ls
• cat
• tr
• wc
• sed (just a few basic things)
• awk (just a few basic things)

They should:

• Motivate why these tools are useful
• Suggest when each tool is the right one to pick

We should test the following learning objectives:

• List the files in a directory with ls
• Show the contents of a file with cat
• Show the contents of a file, including line numbers, with cat
• Replace all occurrences of one character with another using tr
• Count the bytes, words, and lines of a file with wc
• Count just the words of a file with wc
• Remove numbers from the start of lines in a file with sed
• Filter a space-separated file and extract a positional field using awk