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See this page as a slide show

CS155 Commands1

Review

• Information on a Unix system is organized in a tree called the file system.
• All files have an absolute path given their location from the file system root, /, or a user’s home directory.
• On login, our starting point is called the home directory, represented by ~ or ~username
• The current directory is . and the parent directory is: ..
• We can navigate the file system using the Unix commands: pwd, ls, cd

Learning More with man and info

Many Unix command have options that modify their behavior.

To learn more about a specific command try:

• man – show manual for command
• info – show info page for command

Consider them travel guides. man and info can answer many of your questions.

Viewing Files

% cat ~/monster
			/|  /|
			||__||
		       /  o o \__
		      /		 \
		     /	    \	  \
		    /	_    \	   \
		   /	|\____\	    \
		  /	| | | |\____/
		 /	 \| | | |/ |	 __
		/  /  \	  -------  |_____||__
	       /   |   |	   |	   --|
	       |   |   |	   |_____  --|
	       |<–|_|_|_|––<<<	   |	 \----
	       /\		   |
	      / /\	  |	   /
	     / /  |	  |	  |
	 ___/ /	  |	  |	  |
	|____/	  c_c_c_C/ \C_c_c_c

The simplest way to view the contents of a file is to use:

• more – show a file one screenful at a time
• cat – dump the complete file to the screen

Modifying the file system

% ls
% cp ~/monster .
% ls
monster
% cp monster foo
% ls
foo  monster
% mv foo bar
% ls
bar  monster
% rm monster
% ls
bar

Here are three commands for handling files:

• cp – copy a file to some location
• mv – move a file to a new location
• rm – remove a file

Modifying the file system (cont.)

% cp ~/monster .
% ls -l
total 4
-rw------- 1 cs155 class 401 Nov 23 17:19 monster
% mkdir new_dir
% ls -l
total 4
-rw------- 1 cs155 class 401 Nov 23 17:19 monster
drwx------ 2 cs155 class  40 Nov 23 17:19 new_dir
% rmdir new_dir
% ls -l
total 4
-rw------- 1 cs155 class 401 Nov 23 17:19 monster

The previous commands allowed us to move files around in the file system, but what about modifying the structure itself?

• mkdir: make directory
• rmdir: remove directory

echo, echo, echo, echo, echo, echo, echo, echo, echo, echo, echo, echo, echo, echo, echo,

% echo hey children
hey children
% echo hey         children
hey children
% echo "hey         children"
hey         children
% echo "~"
~
% echo ~
/s/bach/a/class/cs155

The echo command prints some text to the screen.

• Use " to preserve text on the command line

Is this useful for anything? Sure!

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