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Week 4 Notes for DAT2330
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-Ian! D. Allen - idallen@idallen.ca

*** Keep up on your readings (Course Outline: average 5 hours/week homework)

Remember - knowing how to find out an answer is more important than
memorizing the answer.  Learn to fish!  RTFM!  (Read The Fine Manual)

Reminder: Midterm Test #1 is in Week #5 (see the Course Home Page).
 - You all were sent email about this test on Sunday January 22.
 - See Notes file termtest1directions.txt for the test format.

In Week 4 (see also week03notes.txt) you did this:

Review Class Notes:

  arguments_and_options.txt  Options and Arguments on Unix Command Lines
  datsubmit.txt         Using the datsubmit command
  file_transfer.txt     File transfer between machines
  home_and_HOME.txt     Directories: current, HOME, and /home
  miscellaneous.txt     Miscellaneous Unix Facts
  pathnames.txt         Unix/Linux Pathnames
  shell_basics.txt      The Unix Shell
  shell_prompt.txt      Setting the BASH shell prompt
  startup_files.txt     Setting up Startup Files: .profile and .bashrc

Readings in "Practical Guide to Linux (2005 edition) [PGL]":

- chapter 1 - welcome to Linux
- chapter 2 - getting started
  - correcting Mistakes
  - getting help (man)
  - consoles
  - password
- chapter 3 - command line utilities (read up on the ones we use)
    ls cat rm cp less hostname mv grep head tail sort uniq diff file echo
    date script unix2dos
    bzip2 bunzip2 bzcat bzip2recover gzip gunzip zcat compress
    tar which whereis apropos slocate who finger w write mesg
- chapter 4 - the linux filesystem
- chapter 5 - the shell
- chapter 6 - the vim editor
  - read up on file locks and aborted sessions p.152
  - concentrate on learning the commands covered in the online vim tutorial

Shell - see Notes files: shell_basics.txt, arguments_and_options.txt
 - arguments_and_options.txt     Options and Arguments on Unix Command Lines
 - shell splits line into separate commands, perhaps joined by pipes
   - pipes separate commands but join output:  grep foo /etc/passwd | wc
   - you can also use ';' to fully separate commands:  sleep 4 ; echo BOO
 - next, shell splits each separate command into options and arguments

More on Pathnames: see Notes file: pathnames.txt
 - New: hidden files, ls -a to see them
 - empty dir ; ls and hidden pathnames (define what is a hidden pathname) 
 - making and removing directories (chapter 4)
   - rm -r to remove a whole directory (not rmdir!)
 - show simple directory traversal
 - absolute path ; relative path  (pathnames.txt)
 - mkdir foo ; cp /etc/passwd foo/bar ; ls
   mkdir bar ; cp /etc/passwd . ; mv passwd bar ; ls
   mkdir xxx ; cp /etc/passwd . ; mv passwd xxx/../yyy ; ls
   Review: cp pwd rm mv
   Review: dot and dot dot
   New: cd, mkdir, rmdir, rm -r

New commands and/or command options (read text chapter 3):
  grep -v -w
  sort -n -u -r
  uniq -c
  diff -u
  which
  whereis
  slocate
  w

New Class Notes presented:
  finding_files.txt     Searching for and finding files by name
  glob_patterns.txt     GLOB patterns (wildcard pathname matching)

Finding Files - see Notes file finding_files.txt

The shell can expand file GLOB patterns - see Notes file glob_patterns.txt
 - similar to DOS wildcard; but, the shell does it, not the command
 - shell helps with wildcards (GLOB) (see shell_basics.txt)
 - See Notes: glob_patterns.txt - GLOB patterns (wildcard pathname matching)
 - Hidden files as (not) seen by ls and glob wildcard *
 - GLOB patterns do not match hidden files unless you
    explicitly include the leading period:  echo .*
 - * matches zero or more characters
 - ? matches a single character (any character, even a space)
 - [abc] matches a single character from the list abc
 - GLOB patterns do not match names that start with a period (hidden
   pathnames), unless you explicitly put the period at the start of
   the pathname component
   $ echo *
   a b c
   $ echo .*
   . .. .bashrc
   $ echo /var/www/html/.*
   /var/www/html/. /var/www/html/.. /var/www/html/.htaccess
   $ echo * a* *b *b* a*a ? ?? ??? a? ???*
 - like ls, GLOB patterns do not match hidden pathnames
   - you can see hidden names using:  ls -a
 - echo *  - does not match hidden pathnames
 - creating command line arguments using quotes and backslashes
 - wildcards (GLOB)
   - mention that, like ls, GLOB patterns do not match hidden names

Hiding GLOB characters from the shell:
 - use single or double quotes to hide GLOB characters:
   $ echo "*** warning ***"

Reminder: Midterm Test #1 is in Week #5 (see the Course Home Page).
 - You all were sent email about this test on Sunday January 22.
 - See Notes file termtest1directions.txt for the test format.