mini exam 1

print

display program output

debug

find and fix program errors

shell

in unix, the primary end-user, command-line interface to the system is a program called

unix system

computer systems that provide a unix environment

operating system

primary piece of software on most computers, a program or collection of programs that manage the computer’s resources for its users and the other programs that those users run

$

represents the prompt

ssh

secure shell comand

pwd

print the absolute path of the current working directory

absolute path of home directory

/home/myid/username

/

represents the root directory of the system, an absolute path always starts with this

print

print the system date and time

exit

exit the currrent shell

whoami

print the user name associated with the current user

ssh user@hostname

start a secure shell connection to hostname and login as user

ls

list contents of the current working directories

ls PATH

list contents of the last directory in the provided PATH

tree PATH

list contents of the last directory in the provided PATH and its subdirectories, in a tree format

ls -l

ls uses long listing formats

ls -l -h

ls uses long listing format with human-readable size units

cd

home directory

cd -

last previous working directory

cd a/b/dest

dest, assuming a is in the current directory and a/b/dest is a valid relative path

cd /a/b/dest

dest, assuming /a/b/dest is a valid absolute path

cd ~/a/b/dest

dest, assuming a is in your home directory and ~/a/b/dest is a valid path

.

path alias for the directory itself

..

path alias for parent of the directory (parent directory)

ls -a

ls shows hidden files (those that start with .)

ls .

ls lists the contents of . (current directory); same as ls with no arguments

ls ..

ls lists the contents of .. (parent directory)

cd ..

cd changes working directory to .. (parent directory; “up one”)

cd ../..

cd changes working directory to ../.. (parent of parent directory; “up two”)

C

CTRL (control)

M

META (meta): usually ALT, OPT, or ESC

S

SHIFT (shift)

C-a

move the cursor to the beginning of the line

C-e

move the cursor to the end of the line

C-f

move the cursor forward (right) one character

M-f

move the cursor forward (right) one word

C-b

move the cursor backward (left) one character

M-b

move the cursor backward (left) one word

C-p

backward one line through the command history

C-n

forward one line through the command history

C-r

reverse incremental search through command history

C-s

forward incremental search through command history

C - < (C-S-)

when in incremental search, move to beginning of command history

C - > (C-S- .)

When in incremental search, move to end of command history

cat

(concatenate [to standard output] command) displays the entire contents of a file all at once

mkdir

make a new directory

mv SOURCE DEST

rename SOURCE to DEST

mv SOURCE … DIRECTORY

move SOURCE(s) into DIRECTORY

cp SOURCE DEST

copy SOURCE to DEST

cp SOURCE … DIRECTORY

copy SOURCE(s) into DIRECTORY

rm

(remove command) to delete a file in Unix

-r

(recursive) option; to make rm recusrively remove the contents of a directory so that it can remove it

emacs

a powerful text editor that can run directly inside the terminalC

C-x C-f

open/find file

C-h t

emacs tutorial

C-x C-c

close/exit emacs

C-x C-s

save current buffer

C-g

quit/cancel a partially typed command

C-v

move down one page

M-v

move up one page

C-l

scroll to make the current line appear in the center, bottom, then top

M-g M-g

go to line (enter the number at prompt, then press RET)

M-<

move to beginning of buffer

M->

move to end of buffer

C-d

forward delete a single cahracter (similar to the delete key)

M-d

forward delete a word

C-x u

undo one batch of changes (usually one command worth)

C-/

undo one batch of changes (usually one command worth)

C-<SPC>

set the mark point (start a selection)

C-k

kill / cut to the end of the line (goes to kill buffer)

C-w

cut selection (goes to kill buffer)

M-w

copy selection (goes to kill buffer)

C-y

paste / yank (from kill buffer)

C-x h

select all

C-s

incremental search (forward direction)

C-r

incremental search (backward direction)

M-%

query replace

C-x 1

close other windows (maximize current window)

C-x 2

split window horizontally (stacked top and bottom)

C-x 3

split window vertically (side-by-side)

C-x o

switch cursor focus to the other window

C-x C-b

list available buffers

packages

used to organized code

simple class name

class name; will always begin with a capital letter; ex) Scanner

package name

will always be lowercase; ex) java.util

fully qualified name (FQN)

ex) java.util.Scanner

primary benefits of packages

1) name space management

2) access protection

src

default package for source code; will contain .java files

bin

default package for compiled code; will contain .class files

-cp

class path; the path to default package for compiled code

-d

destination

javac

compilation command