Homework: Scripting in the shell

For the homework assume you$$re in the standard C or POSIX locale. The shell command locale should output LC$\_$CTYPE$="$C$"$ or LC$\_$CTYPE$=$"POSIX". If it doesn$$t$,$ use the following shell command:

export LC$\_$ALL$=\text{'}$C$\text{'}$

and make sure locale outputs the right thing afterwards.

Shell scripting

Steve Parker, Shell Scripting Tutorial $(2023)$

The Open Group, Shell Command Language $(2018).$ This is the standard for POSIX shells, and you are not expected to read it all, though it can be handy to refer to it$.$

Read enough about the shell to understand how to do I$/$O redirection and pipes.

For each command tr$,$ sort, comm, read the command$$s man page and use that to deduce what the command should do given its operands shown below.

Examine the SEASnet file $/$usr$/$share$/$dict$/$linux$.$words, which contains a list of English words, one per line. Each word consists of one or more ASCII characters.

Use sort with $<$ and $>$ to sort this file and put the sorted output into a file sorted.words.

Then, take a text file containing the HTML in this assignment$$s web page, and run the following commands with that text file being standard input. Also, look generally at what each command outputs $($in particular, how its output differs from that of the previous command$),$ and why.

tr $-$c $\text{'}$A$-$Za$-$z$\text{'}\text{'}[$

$*]\text{'}$

tr $-$cs $\text{'}$A$-$Za$-$z$\text{'}\text{'}[$

$*]\text{'}$

tr $-$cs $\text{'}$A$-$Za$-$z$\text{'}\text{'}[$

$*]\text{'}|$ sort

tr $-$cs $\text{'}$A$-$Za$-$z$\text{'}\text{'}[$

$*]\text{'}|$ sort $-$u

tr $-$cs $\text{'}$A$-$Za$-$z$\text{'}\text{'}[$

$*]\text{'}|$ sort $-$u $|$ comm $-$ sorted.words

tr $-$cs $\text{'}$A$-$Za$-$z$\text{'}\text{'}[$

$*]\text{'}|$ sort $-$u $|$ comm $-23-$ sorted.words

Let$$s take the last command as the crude implementation of an English spelling checker. This implementation mishandles the input file $/$usr$/$share$/$dict$/$linux$.$words! Verify this by running a command like this and inspecting the output:

tr $-$cs $\text{'}$A$-$Za$-$z$\text{'}\text{'}[$

$*]\text{'}$ my$.$words

Submit

myspell. This should not have a file name extension; for example, it should not be myspell.sh$.$

makedict. This also should lack a file name extension. Do not submit this file if your myspell script can operate without an auxiliary dictionary file to read.