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Ch 4 UNIX Shells
UNIX The Textbook 2nd edition
44
Computer Science
Undergraduate 2
09/29/2014

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Term
a program that acts as in interface between you and the UNIX kernel
Definition
shell
Term
the shell is also known as the UNIX ___ ___ because the primary purpose of the shell is to interpret your commands
Definition
command interpreter
Term
as soon as the shell receives this keyboard command it terminates and logs you off the system
Definition
Ctrl-D
Term
the names of the directories that a shell searches to find the file corresponding to an external command are stored in the shell variable ____
Definition
PATH
Term
The directory names stored in the PATH variable form what is known as the ___ ___ for the shell
Definition
search path
Term
You can view the search path for your variable by using the ___ ___ command
Definition
echo $PATH
Term
these files are used to set up and configure the operating environment within which programs execute. When you list the names of files contained in your home directory these files do not appear on the list.
Definition
hidden (dot) files
Term
You can determine you login shell by using this command
Definition
echo $SHELL
Term
When you log on one particular type of shell starts execution and it is determined by the system administrator
Definition
login shell
Term
the most popular LINUX shells
Definition
Bash, TC, and Z shells
Term
the most common UNIX shells
Definition
Bourne, C, and Korn shells
Term
A shell is essentially an ____ program
Definition
interpreted
Term
give the location and program name of the rc shell
Definition
/usr/bin/rc rc
Term
give the location and program name of the Bourne shell
Definition
/usr/bin/sh sh
Term
give the location and program name of the C shell
Definition
/usr/bin/csh csh
Term
give the location and program name of the Bourne Again shell
Definition
/bin/bash bsh
Term
give the location and program name of the Z shell
Definition
/usr/bin/zsh zsh
Term
give the location and program name of the Korn shell
Definition
/usr/bin/ksh ksh
Term
give the location and program name of the TC shell
Definition
/usr/bin/tcsh tcsh
Term
How do you change your default shell after you have logged in
Definition
type csh + and the location of the shell program name you want to change to (/user/bin/sh)
Term
use this command terminate or leave a temporary shell and return to your default login shell
Definition
Ctrl+D
Term
can more than one shell program be active at the same time to interpret commands? if so, briefly describe why.
Definition
yes, because UNIX is a multi-process os so more than one command line interpreter at a time can be active. Input, output, and errors are hooked into whatever shell process has control over them currently.
Term
If you type echo $SHELL on the command line and get the response /usr/bin/sh, what shell are you currently running
Definition
Bourne shell
Term
If you type ls *.doc on the UNIX command line, and then press the Enter key, what do you see displayed on screen?
Definition
Any files with the file extension .doc in the current working directory will be displayed
Term
If you type cat > file1 on the UNIX command line, and then press Enter key, what happens?
Definition
Whatever you type on the keyboard will be entered into a file named file1, in the current working directory, until you type Ctrl+D
Term
Each UNIX system has an intial start-up file, usually named ____. This file contains the initial settings of important invironment variables for the shell and some other utilities
Definition
.profile
Term
Characters that have special meaning to the shell
Definition
metacharacters
Term
What shell metacharacter provides for background execution of a command
Definition
Ampersand(&)
Term
What shell metacharacter matches zero or more characters
Definition
Asterisk(*)
Term
What shell metacharacter starts a comment
Definition
# (pound sign)
Term
What shell metacharacter is used to quote multiple characters but allow substitution
Definition
" (double quote)
Term
What shell metacharacter is used to end line and dereference a shell variable
Definition
$ (dollar sign)
Term
What shell metacharacter is used to quote multiple characters
Definition
' (single quote)
Term
What shell metacharacter is used to execute a command list in a subshell
Definition
( )
Term
What shell metacharacter is used to insert wildcards
Definition
[ ]
Term
What shell metacharacter is used to begin a line with a negation symbol
Definition
^ (caret)
Term
What shell metacharacter is used to execute a command list in the current shell
Definition
{ }
Term
What shell metacharacter is used to create a pipe between shells
Definition
| (pipe)
Term
What shell metacharacter is used to seperate commands in sequential execution
Definition
; (semicolon)
Term
What shell metacharacter is used to redirect input for a command
Definition
< (redirection)
Term
What shell metacharacter is used to redirect output for a command
Definition
> (output redirection
Term
What shell metacharacter is used to substitute a wild card for exactly one character
Definition
? (question mark)
Term
What shell metacharacter is to be used as the root directory and as a component seperator in a pathname
Definition
/ (forward slash)
Term
What shell metacharacter is used to escape/quite a character to allow continuation of a shell command on the following line
Definition
\
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