Final Flashcards
UNIX was created in the:
UNIX was created at:
1970’s
AT&T Bell Laboratories in Murray Hill , New Jersey .
Who owns Bell labs?
Nokia
The original Unix development team included:
Ken Thompson, Dennis Ritchie and many other individuals .
Unix distinguishes itself from its predecessors as the first portable:
operating system
The Unix operating system is almost entirely written in the _________ programming language, which allows Unix to operate on numerous platforms.
C
The C programming language was also written by:
, so it should be no surprise that their Unix operating system is written in C.
Ken Thompson
And Dennis Ritchie
The AT&T UNIX operating system was originally developed to support activities within:
AT&T Bell Labs
Other organizations began developing their own Unix operating systems during:
1970’s and early 1980’s.
rise to the “Unix Wars during the late 1980s and early 1990s where multiple hardware vendors attempted to:
for Unix .
set the standard
List the 7 Unix wars vendors:
AT&T System 5 UNIX (Sys5)
University of California, Berkeley (BSD)
Microsoft (Xenix )
Sun Microsystems (SunOS / Solaris ) Hewlett-Packard (HP-UX)
IBM ( AIX)
Silicon Graphics ( IRIX)
operating system variants, which are able to run on personal computer architectures
Linux
Name 6 Linux operating system variants:
Ubuntu, Gentoo , Red Hat, Debian, CentOS, Linux Mint
Two methods to remotely acces a computer running the Unix os:
- Invoke a client communication program (e.g. PuTTY) on an Internet connected computer
- Via a dedicated “ dumb” terminal and keyboard Rarely used today
Once a connection is made with the Unix computer , you will be challenged to enter:
both a login identification (use rid) and a password
If userid /password combination is valid , you will see:
the Unix system prompt for your default Unix shell
After you initially login to your Unix account, you should:
change the password that was initially assigned to your account.
How do u change password?
Type command $passwd
enter your current password
enter your new password twice
Enter any of the three commands at the shell prompt to terminate a Unix session:
logout
exit
ctrl+d
represents the execution of a program that provides an environment which allows you to interact with the UNIX operating system .
shell session
To invoked a new shell session, simply:
enter the name of the shell to use at the current shell prompt
If you terminate the current shell session:
the previous shell resumes
If you precede the new shell with the ________ command, then all previously invoked shell sessions disappear .
exec
Ex: $exec bash
$exec /bin/bash
All OS’s implement a ____ control system, or ______________.
file
File system
Unix and most , if not all, others use a _________________________ structure .
hierarchical directory tree
Within a hierarchical directory tree structure, only two types of entities exist
( 1) Directories
(2) Files
______ are organized under Directories
Files
Unix’s tree is relatively ____________.
The top most directory is called _______
and is designated by a:
standardized
root
forward slash /
First level directories are shown below:
root
Other directories can be created and reside within existing directories under:
root /
By default/design you always log into your:
home directory or login directory.
Your home directory name will be the same as your:
Warhawks userid!
Home directory’s resides under:
/home
/home/userid
To identify your “present working directory type the command:
pwd
is a sequenceof directory names , separated by “, leading to a final directory or file.
A pathname or path
The directory you’re currently in is referred to as the:
present working director
The systems root directory is ALWAYS:
/
There are two types of paths:
Absolute
Relative
Is always referenced from the root directory
E.g. /home/jdoe/public/assignments
Absolute path
Is always referenced from the “present working directory” directory.
E.g. public /assignments
Relative path
represents the present working directory
represents the parent directory of the present working directory
represents the root directory
represents the user’s directory
.(i.e. dot)
..(i.e. double dot)
/(i.e. slash)
( i.e. tilde)
All ____________ are files but, all files are not ____________!
programs
programs
Files data ->
Programs ->
Data->
programs , etc.
executable instructions , binary images , script /macro , “ run on their own “ etc.
text , databases , graphics , audio , etc.
To determine the “type” of an unknown file, issue the command:
file
Often, we can determine the “type “ of a file by its _________ filename.extension
The part of the filename to the right of the period is called the:
extension
With respect to filenames, all alphanumeric characters are acceptable except:
@ ‘ | < > ! $ & \ / “ ? [ ] ( ) { } ^ # ;
The maximum filename length is ______________ including any extension and intervening periods
255 characters
True or false:
Unix in general is not case sensitive
False:
Unix is case sensitive
Any filename, or directory, that begins with a period (.) is called:
invisible/ hidden file
by default not be shown by a directory listing command
Hidden files
Only one file or directory can exist in a directory with a given:
Likewise , a file and a directory cannot share the same ______ in any directory
name
name
Good filename practice include:
- Use meaningful names
- Use “_” instead of spaces
- Establish your own naming convention
If a file contains text or readable data, then you can display a count of lines, words and characters in the file to standard output without editing it by issuing the command:
wc
4 Command line arguments:
c - count bytes
m - count characters
l - count lines
w - count words
If a file contains text or readable data, then you can display the entire contents of the file to standard output without editing it by issuing the command:
cat
Command line arguments:
n - line number on outputs
# - number of lines to display
c - clear standard output
i - prompt to overwrite
To display the first few lines of the file to standard output without editing , issue the command:
head
To display the last few lines of the file to standard output without editing, issue the command:
tail
To display the entire contents of the file to standard output page by page and without editing, issue the command at the shell prompt:
more
While the more program executes, you can issue several single character commands to interact with the program:
q - Quit
f- Move forward through the file Spacebar - move forward through the file .
b - Move backward through the file
To copy the contents of a source file to a destination file in the present working directory, issue the command:
cp
To copy the contents of a source file to a a new directory where the new file has a new name, issue the following cp command at the shell prompt:
cp [-i] srcFile path/destFile
If the destination file does not exist:
If the destination files exists:
a new file is created
then the prior file contents are overwritten
To rename a file in the present working directory issue the following command at the shell prompt:
mv [-i] srcFile destFile
To move a file from its present working directory to a new directory issue the following mv command at the shell prompt:
mv [-i] srcFile path
To move a file from its present working directory to a new directory AND rename the file, issue the following mv command at the shell prompt:
mv [-i] srcFile path/destFile
To delete a file in the present working directory, issue the following rm command at the shell prompt:
rm [-i] name
To delete a file in any directory, issue the following rm command at the shell prompt:
rm [-i] path / name
To list the files and directories under the present working directory” type the (list) command at the shell prompt:
ls
