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

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

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Review
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In Week 3 (week03notes.txt) you added these commands/options to your list
of known Unix commands (see Notes file unix_command_list.txt):
    apropos sum last sleep hostname head(-5) tail(-5)
    passwd tr diff cut awk($1) uniq wc(-lwc) ls(-sd) sort(-rn) grep(-v)

You can search using / in MORE and LESS.
You know many ways of getting out of programs.
You can create a valid Assignment Label.
You understand shell redirection, pipes, and /dev/null.
You know about Unix line-end characters in text files.
You can translate any set of characters to any other set.
You can compare two text files.
You can use arguments to head and tail to select any range of lines.
You can select fields from input lines (know two commands to do this).

You did readings in Learning Unix and Running Linux.
You read selected files under the course Notes button.

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This Week (Week 4)
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1.  Understand Unix redirection into files and into programs,
    including stdin, stdout, and stderr:
    - all these:  >  >>  <  |  1>  2>  2>&1
    - Running Linux: "Saving Your Output" p.93
    - Learning Unix: Chapter 5 - Redirecting I/O (all)
    - file redirection.txt under Notes

2.  Understand Unix GLOB patterns:  *  ?  []
    - Running Linux: "Filename Expansion" p.92
    - Learning Unix: Chapter 4 - File Management (Wildcards p.67)
      $ echo *      - no hidden files
      $ echo ?*     - no hidden files
      $ echo [.]*   - no hidden files (this pattern never matches anything)
      $ echo .*     - only hidden files (including . and .. )
      $ echo /*/passwd           - all directories under ROOT containing passwd
      $ echo /*/*/passwd         - down exactly two levels (not just one)

3.  A partial list of special shell meta-characters you know:
      # $ * | \ [] ; " ' <> ?
    (There are even more special characters that you don't know yet.)
    All the above are interpreted by the shell unless they are quoted.
    Quoting is used to hide metacharacters (including blanks) from
    the shell:  echo 'hello # $ * | \ [] ; " <> ?' "'"

4.  You can put multiple commands on one line by separating them with
    the semi-colon shell metacharacter:  date ; who ; ls ; pwd
    Every command is separate; redirection applies only to a single
    command, not to the whole line.  (To redirect the whole line, put
    parentheses around it and put the redirection outside.)

5.  You can write a simple executable shell script, using a first line of:
    #!/bin/bash -u
    and then:  $ chmod +x myscript.sh
    and then:  $ ./myscript.sh
    You can choose a different shell or program by changing the first
    line.  The Unix kernel reads this first line to know which program
    to use to execute your script.  The first line is a comment (ignored)
    when read by any of the shells.

6.  You know about the argv.sh script that prints its arguments:
    $ ./argv.sh one "two three"     four
    Argument 0 is [./argv.sh]
    Argument 1 is [one]
    Argument 2 is [two three]
    Argument 3 is [four]

7.  You heard about inodes and hard-linked file names:
    links_and_inodes.html  Hard links and Unix file system nodes (inodes)
    file_system.txt        Unix/Linux File System - (correct explanation)
    Examples (most done in class):
    $ touch a ; ln a b
    $ ls -il a b
    $ touch a ; ls -il a b
    $ chmod +x a ; ls -il a b
    $ date >a ; ls -il a b ; cat b
    $ wc a >b    - tricky! - never use same input file for output!

8.  You learned of the "script" command that will record a terminal
    session for you:

    $ script
    Script started, file is typescript
    $ 
    ... execute many commands here ...
    $ exit
    Script done, file is typescript
    $ less typescript

9.  Start work on DAT2330 Exercise #2.  Submit it by the due date.

10. Study for the Midterm Test Friday, February 6:

    Midterm Topics
    --------------

  * Running Linux:
    "Intro", "Logging In", "Setting a Password", "Virtual Consoles" p.81-84
    "Directories", "Listing Files" p.84-86
    "Viewing Files" p.86-87
    "Shells" p.88-89
    "Useful Keys" p.90
    "Typing Shortcuts", "Word Completion" p.91
    "Moving Around Among Commands" p.92
    "Filename Expansion" p.92
    "Saving Your Output" p.93

  * Learning Unix:
    Chapter 1 - Getting Started
    Chapter 3 - Using your Unix account
    Chapter 4 - File Management
    Chapter 5 - Redirecting I/O

  * Notes: 
    pathnames.txt              Unix/Linux Pathnames
    redirection.txt            Unix Shell I/O Redirection
    miscellaneous.txt          Miscellanous Unix Facts
    internet_basics.html       Internet Networking Basics, URLs, etc.
    home_and_HOME.txt          Directories: current, HOME, and /home
    arguments_and_options.txt  Options and Arguments on Unix Command Lines
    quotes.txt                 Unix/Linux Shell Command Line Quoting
    shells.txt                 The Unix Shell
    man_page_RTFM.txt          Searching for items in the manual pages (RTFM)
    file_system.txt        Unix/Linux File System - (correct explanation)
    links_and_inodes.html  Hard links and Unix file system nodes (inodes)
    stdxxx.c++.txt         C++ program using stdout, stderr, stdin.

  * Practice:
    practiceTest1.*         Practice Test (PDF, PS, and TXT format)
    practiceCommands_1.txt  Practice commands

    I will not be asking questions about how to use the VIM editor on
    this test.