Tasks

One of these files has a space in its name. Print its contents, in a single command, with nothing on standard error.

par 1 command

There is a file called -rf.txt. rm will read that name as options. Remove it anyway, and leave everything else alone.

par 1 command

Put *.txt in a variable, then use it so that it expands to the matching filenames.

par 2 commands

Try to read a file that is not there, then print the status it left behind — and no other output.

par 2 commands

Write ready into the named file, but only if that file does not already exist. One line.

par 1 command

A pipeline whose first stage fails reports success. Turn on the option that changes that, run one, and print the status.

par 3 commands

Read one file that exists and one that does not. The error goes into errors.txt; the output stays on the terminal.

par 1 command

Print the first line of big.txt. The answer is graded on what it read as well as what it printed — a pipeline that reads the whole file does not pass.

par 1 command

Sort the words, save the sorted list to sorted.txt, and count the lines — all in one pipeline.

par 1 command

Take three lines from something that never stops on its own. The pipeline has to terminate.

par 1 command

Run something that fails in the background, then report the status it exited with. $? straight after an & will not tell you.

par 2 commands

Print how many lines of app.log mention ERROR. Just the number.

par 1 command

Print each distinct word once, with how many times it appeared.

par 1 command

Print only the second colon-separated field of every line.

par 1 command

Print app.log without any of its DEBUG lines. The file itself must not change.

par 1 command

Every ERROR in app.log should read FAILURE afterwards — in the file, not just on screen. Check it before you commit to it.

par 1 command

Print the second column of table.txt. The columns are not aligned, and that is the point.

par 1 command

Print the sum of the second column of table.txt, and nothing else.

par 1 command

Print the name from every row of table.txt whose second column is more than 40. grep compares text, so it will not do.

par 1 command

Give the file a second name without making a second copy of it. Copying is not allowed here.

par 1 command

List every .txt file anywhere below the current directory, one per line.

par 1 command

Set the top-level directory so somebody may read a file inside it if they know the name, but may not see what is there.

par 1 command

Print every line of words.txt wrapped in square brackets, using a while read loop. sed is not allowed: this task is about the loop.

par 1 command

Write a function that sets count without disturbing the caller's value, then show that it did not.

par 4 commands

Create a two-line file with a here-document rather than two separate echo commands.

par 1 command

Set the positional parameters, then print each one on its own line — including the one with a space in it.

par 2 commands

Write a script taking -v and -o FILE, which then reports what it was given and what was left over. The operands must survive.

par 2 commands

DIR is not set, and the line is rm -rf "$DIR/". Print what that line would actually hand to rm — without handing it to rm.

par 1 command

The documentation says curl -fsSL https://example.test/install.sh | sh. Do it the other way round: save the script, then report how many of its lines contain rm -rf.

par 2 commands

clean.sh runs rm -rf "$BUILD"/* and nothing sets BUILD. Add the one line that makes it fail instead of emptying this directory, immediately after the shebang. Do not run it to find out.

par 1 command