CSI 3336 Aars Final

Linus Torvalds, Helsinki

Who created Linux and where?

Bell laboratories

Where was C/Unix created?

Dennis Ritchie/Bryan Kernigan

Who co-created C?

GNU Public License

Software License GPL

/bin

Machine code path

/usr/bin

Apps/program files

usr/sbin

Admin programs

.a

Unix static library

.lib

Windows static library

.so

Unix shared library

.dll

Windows shared library

Kernal is the core of the OS

What is a kernal?

Shell is the program that interfaces with the driver of the hardware

What is a shell?

C Shell

CSH

Bourne Again Shell

BASH

Korn Shell

KSH

zero or more

* (cmd line)

Two copies, if one is deleted, the other does not exist

Hard link

A file with a reference to another file

Soft link

*, ~

" " suppression

*, ~, variables, commands

' ' suppression

feeds input to command. Right to left

<

Overwrites to file

>

Appends to file

>>

feeds input to command. Left to right

|

?

Replaces a single character

Library

Multiple pieces of object code

Static library

Multiple instances with the linker

Shared Library

One single instance

Set shows shell variables, env only shows environmental variables

set vs env

export

create environmental variables

matches single char

. (regex)

0 or more of previous pattern

* (regex)

character class

[] (regex)

Anchor to beginning

^ (regex)

Anchor to end

$ (regex)

Matches n # of previous pattern

{n} (regex)

at least n# of previous pattern

{n,} (regex)

at most n# of previous pattern

{,n} (regex)

range

{n, m}

1 or more of previous pattern

+ (regex)

0 or 1 of previous pattern

? (regex)

capture group

() (regex)

"(.)\1\1.*\1\1\1"

double triple (regex)

copies files from one box to another

SCP

#! - path to executable to be interpreted

What is the shebang line?

return value

$? (scripting)

name of script

$0 (scripting)

number of arguments

$#

$$ (scripting)

process ID of the script

all parameters

$@ (scripting)

certain argument # n

$n (scripting)