The Command Line

cornawakeSoftware and s/w Development

Nov 4, 2013 (4 years and 5 days ago)

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Section
-
3

The Command Line

Shell Architecture

The
Tenex

C shell


The

C

shell

was

developed

for

Berkeley

Software

Distribution

(BSD)

UNIX

systems

by

Bill

Joy

while

he

was

a

graduate

student

at

the

University

of

California,

Berkeley,

in

1978


One

of

the

key

design

objectives

for

the

C

shell

was

to

create

a

scripting

language

that

looked

similar

to

the

C

language
.


A

useful

feature

introduced

by

Bill

Joy

in

the

C

shell

was

command

history
.


Korn

Shell


The

Korn

shell

(
ksh
),

designed

by

David

Korn
,

was

introduced

around

the

same

time

as

the

Tenex

C

shell
.


Korn

shell

used

as

a

scripting

language

in

addition

to

being

backward
-
compatible

with

the

original

Bourne

shell
.



Environment Variables


Environment Settings that give it a particular
look, feel, and, in some cases, behavior.


Defining your own and using them for your
own needs.


printenv



Pipes


Pipes

are

a

mechanism

by

which

the

output

of

one

program

can

be

sent

as

the

input

to

another

program
.

Individual

programs

can

be

chained

together

to

become

extremely

powerful

tools
.


printenv

|

grep

TERM


Redirection


Through

redirection,

you

can

take

the

output

of

a

program

and

have

it

automatically

sent

to

a

file
.


Redirection

comes

in

three

classes
:



output

to

a

file



append

to

a

file



send

a

file

as

input
.

The man Command


Manual Section Subject

1 User tools

2 System calls

3 C library calls

4 Device driver information

5 Configuration files

6 Games

7 Packages

8 System tools


Text info system


Another common form of documentation is
texinfo
.


info
grub