NDOS515_Session_2

Question 1

How to Organize your tree…?

Answer 1

• Some conventions:
  
  • Desktop shows up on your GUI desktop
  • Documents for …. documents.
  • bin holds “binaries” and executable scripts
  • public_html (sometimes) has your Web page(s)
• Otherwise, pretty wide open
  
  • Two suggestions:
    
    1. Think about it early on
    2. Be willing to reorganize from time to time.

Question 2

Navigating on Command line

Answer 2

• pwd tells where you are
• cd to get to a new directory (folder)
• ~ refers to your home
  
  • cd ~
  • cd ~/music
• Leading slash (or ~) means “start at top”
  
  • Absence of slash means “from here”
  • cd ~/music/elvis
  • cd ~/music; cd elvis

Question 3

Linux Standard Directories

Answer 3

/bin		Important executables
/etc		System configuration
/home	User homes
/tmp		Temporary files
/usr/bin	More executables

(There are more than just these…)

Question 4

Redirection…?

Answer 4

The output of any command can be captured into a file:
ls > listing.txt
(Note: “.txt” isn’t necessary and is omitted by experienced Unix users)

You can add to a file, too:
ls /bin&raquo_space; listing.txt

Question 5

Viewing files…?

Answer 5

Short files can be viewed with cat:
	cat listing.txt
For longer ones, use less:
	less bigfile
(type space to see more, q to quit, h for help)
Use file to find out what something is:
	file /etc/passwd

Question 6

Copy, rename/move, delete…?

Answer 6

cp coolstuff coolstuff.bak
mv coolstuff.bak backup
mv backup my-backups/coolstuff.bak
rm my-backups/coolstuff.bak

Question 7

A Philosophical Note…?

Answer 7

Unix (and Linux) is designed on the assumption that you don’t like chatty computers
Success is generally indicated by silence:
rm backup
rm backup2
rm: cannot remove `backup2’: No such file or directory

Question 8

Directory Management…?

Answer 8

For historical reasons, directories are handled differently:
mkdir backups
rmdir obsolete
cp –r public_html backups/web-backup
rm –r backups
WARNING!!! rm –r is extremely dangerous. Never type Enter until you’ve triple-checked what you typed!

Question 9

Globbing…?

Answer 9

It’s a pain to type lots of file names, so you can abbreviate:
ls a*
less *.txt
	(omits files starting with dot…why?)
ls .??*

More choices, but these are common ones

Question 10

Editors..?

Answer 10

What’s an editor?
- Shows you exactly what’s in the file
- Give you control over file contents
- Can be hard to learn
What’s a word processor?
- Usually easy for beginners to get started
- Puts priority on formatting and layout
- Shows you what printed page will look like
- File contents are very different from what you see

Question 11

Simple Editors on Linux

Answer 11

Nano
 - Command-line
 - Fairly easy to start with
 - Word-wraps by default, which can be problematic
gedit
 - GUI
 - Easy to get going

Question 12

Powerful Linux Editors

Answer 12

vi
- Command line
- Hard to learn
- Modal
- Popular with many (because they learned it first?)
emacs
- Command line or GUI
- Hard to learn
- Amazingly powerful and flexible (too much?)
- Lets you click, type, use arrow keys and mouse (non-modal)

Question 13

Religious Wars

Answer 13

Linux users get heated about editors
Criticize non-favorites, support their own
Don’t make decisions based on logic
Best way to choose an editor:
1. Decide how much work you’re willing to put out
2.Try at least two
- Give enough time to actually learn them well
- Choose significantly different ones
3. Pick based on what fits your preferences & needs
- DON’T choose one just because your friend uses it

Question 14

The second lab

Answer 14

Review of
The ls, cat commands; file system layout and navigation.
Globbing
File redirection.