Updated: 2017-03-13 09:08 EDT
touch
vi/vim, nano
head, tail
cat, more, less
head, tail
mkdir
mv
(including using ..
)cp
rm, rmdir
find
using “wildcard” (GLOB) patterns - same as shell GLOB.bash_history
fileCheck the due date for each assignment and put a reminder in your agenda, calendar, and digital assistant. Just like in the Real World, not all due dates are on the same days or at the same times.
PS1 find mkdir mv cp rm touch file
PS1 find mkdir mv cp touch file
Worksheets are preparation for your assignments. You can’t do the assignments without having done the worksheets first, and you can’t do the worksheets without having first read the Course Notes: 1. Read. 2. Worksheet. 3. Assignment.
Form a small study group to do the worksheets. Each person tries the example given, and you make sure you all get the same answers. Worksheets are not for hand-in; they are not worth marks; the assignments test your knowledge of the lectures and worksheets.
The worksheets are available in four formats: Open Office (ODT), PDF, HTML, and Text. Only the Open Office format allows you “fill in the blanks” in the worksheet. The PDF format looks good but doesn’t allow you to type into the blanks in the worksheet. The HTML format is crude but useful for quick for viewing online.
Do NOT open the Worksheet ODT files using any Microsoft products; they will mangle the format and mis-number the questions. Use the free Libre Office or Open Office programs to open these ODT documents. On campus, you can download Libre Office here.
These first two worksheets require you to have read File System and Pathnames:
PS1, cd, find, less, ls, man, mkdir, passwd, pwd, rmdir
cat, clear, cp, find, fgrep, history, less, man, mv, rm, sleep, touch
alias, sum, unalias
vim
vimtutor
program on the CLS.Worksheets prepare you for the upcoming assignments.
For full marks, read the Test Instructions (all the words) before your midterm tests. Use the Name Game link to test your name before the test. I don’t answer questions about the instructions during the test.
Tests take place at 10am in your 50-minute lecture class, not in your lab period. Each midterm test is 45 minutes long and contains approximately 45 multiple-choice questions.
Take notes in class! Keep a pad open on your desk.
This week, we finish with using pathnames and learn how to find files and match file names with GLOB patterns.
Students will have their CLS accounts disabled if they have not changed their default password. (I do not want people breaking into my machine because of you.)
See my online timetable for how to make an office appointment to see me if you want your account back.
See the note in Assignment #03 HTML about drawing file system diagrams on paper. Do it!
Keep a notebook with a List of Commands in it.
- You need to write down yourself what each command does.
- Check the updated list of commands each week.
- I will check for this list in your lab periods.
You can tell whether a file system name is a directory or a file by using the file
command or by looking for a letter d
on the left in the output of ls -l
. Ordinary files are indicated by a dash -
character on the left. The first two lines, below, are files. The last three are directories.
$ ls -l /
-rw-r--r-- 1 root root 22528 Sep 4 11:01 aquota.group
-rw-r--r-- 1 root root 73728 Sep 4 11:01 aquota.user
drwxr-xr-x 2 root root 4096 Jul 1 15:57 bin
drwxr-xr-x 3 root root 4096 Sep 2 17:58 boot
drwxr-xr-x 2 root root 4096 Sep 7 2012 cdrom
rmdir
command will only remove an empty directory.
The copy command cp
will not copy directories unless you use the right option. (You know this option from doing Section 3 of Worksheet #03 HTML.)
cp
and rename/move command mv
can both accept a directory as the destination, and will put all the source files into that destination directory using the source file name(s):
bar
is a directory, then cp foo bar
creates file bar/foo
bar
is a directory, then mv foo bar
creates file bar/foo
bar
is not a directory, then cp foo bar
creates file bar
bar
is not a directory, then mv foo bar
creates file bar
You can use pathnames anywhere you can use a file name, even for output redirection, e.g.:
$ date >date.txt # date.txt in the current directory
$ date >../date.txt # date.txt in the parent directory
$ mkdir foo
$ date >foo/date.txt # date.txt in the foo directory
$ mkdir foo/bar
$ date >foo/bar/date.txt # date.txt in the foo/bar directory
You will need to know this for Assignment #03 HTML.
Commands to show the number of locked out IP addresses and attempts to use locked-out IP addresses in /etc/hosts.evil
:
$ wc /etc/hosts.evil
$ fgrep -c 'refused' /var/log/auth.log
$ fgrep 'refused' /var/log/auth.log | less
Count the unique locked-out addresses, and then show the top twenty:
$ fgrep 'refused' /var/log/auth.log | awk '{print $NF}' | sort -u | wc
$ fgrep 'refused' /var/log/auth.log | awk '{print $NF}' | sort | uniq -c | sort -nr | head -n 20
Password failures:
$ fgrep -c 'Failed' /var/log/auth.log
$ fgrep 'Failed' /var/log/auth.log | less
Userid failures:
$ fgrep -c 'input_userauth' /var/log/auth.log
$ fgrep 'input_userauth' /var/log/auth.log | less
You can use the whois
command on Linux to identify which country is responsible for an IP address, or use a Web Whois Lookup. (The Linux whois
command is blocked from use at Algonquin College, except if you are on the CLS. You can’t use the Linux command in your own Linux machines on campus. Use it on the CLS or use the web interface instead.)
When you are locked out, follow the directions in the notes to get your IP address re-enabled.