Samenvatting Operating Systems-1

Operating systems samenvatting
Inhoud
Inleiding..................................................................................................................................................3
Shell........................................................................................................................................................4
Tekstbestanden......................................................................................................................................9
Bestandsbeheer....................................................................................................................................15
Scripts – deel 1.....................................................................................................................................19
Herhaling..........................................................................................................................................19
Eenvoudige scripts............................................................................................................................20
Variabelen........................................................................................................................................22
Back quotes......................................................................................................................................25
Argumenten......................................................................................................................................26
Log files.............................................................................................................................................26
Scripts deel 2........................................................................................................................................27
Exit codes..........................................................................................................................................27
Condities...........................................................................................................................................28
Functies............................................................................................................................................32
Iteraties............................................................................................................................................33
Switch-case.......................................................................................................................................34
Gebruikers en permissies.....................................................................................................................35
Gebruikers en groepen.....................................................................................................................35
Permissies.........................................................................................................................................38
Proces- en pakketbeheer......................................................................................................................40
Pakketbeheer...................................................................................................................................40
Procesbeheer....................................................................................................................................42
Schijfbeheer..........................................................................................................................................44
Opslag en partities............................................................................................................................44
Koppelen van een file system...........................................................................................................46
Swap space.......................................................................................................................................47
Diskruimte........................................................................................................................................47
Aanvulling oefeningen..........................................................................................................................48
Week 9..............................................................................................................................................48
Week 11............................................................................................................................................49
11.2...............................................................................................................................................49


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,Inleiding
 Operating systems
o = Linux
 Bash command line (commando’s geven)
 Bash scripting (automatiseren)
 Gebruik je op servers,… Praktisch alles wat in de cloud zit
o Elke machine heeft een operating system nodig
 Real-time OS = heel specifiek
 Bv.: Windows, Mac, IOS, Andriod
o (word, browser, … communiceren allemaal met het operating system)
o UNIX
 = één van de eerste OS, closed source (alleen de makers konden er aan
werken, andere mensen konden er niet dingen in aanpassen + was betalend)
 Kleine programma gecombineerd <-> Windows is één groot bestand
 Hierdoor minder kans op bugs
 Programma’s werken met tekstbestanden (ASCII of unicode) als input-output
 UNIX kernel
 Taken
o Hardware aansturen (muis, scherm, …)
o Booting / opstarten
o Bestandsbeheer
 Harde schijf > (opgedeeld in) partities > blokken data
o Procesbeheer
 Beheert meerdere applicaties tegelijkertijd
o Geheugenbeheer
o …
 Zonder kernel moet iedere applicatie dit allemaal zelf doen
 Multi-user (gebruikers kunnen tegelijkertijd op één systeem, via
terminals
 Interactie met gebruiker via terminal (tekst) of X-terminal (grafisch)
 Multitasking
 “Processor onafhankelijk”: grotendeels geschreven in C
 Geschiedenis
o 1965: UNIX, C (closed source door Ken Thompson en Dennis Richie)
o 1985 – 1989: Open source, GNU (Richard Stallman)
 GNU is Not Unix (open sourcebeweging)
 GPL (= Gnu Public Licence)
 Free speech <-> free beer (GNU hoeft niet persé gratis te zijn)
 LibreOffice, Firefox, Wikipedia, …
o 1987: Minix (Andrew S. Tanenbaum)
o 1991: Linux kernel: Linus Torvalds
 Kernel = stuk van een operating system




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,  Schema operating system:




 Open source
o Software (LibreOffice, Audacity,…)
o Boeken (vb. Boek linux, cursus hardware)
o Processoren (vb. MIPS, Sun Sparc, Moncky, …)
o Hardware (Thingiverse) -> gebruikt om voorwerpen 3D te printen
o Auto’s (wikispeed,…)
o …
o Veel versies
 Veel distributies van GNU/Linux
 Debian based (ubuntu)
 Redhat based (Fedora)
 Oracle
 …

Shell
 Command prompt (= command line)
o In Windows:
 “DOS” prompt (= tekstgebaseerde gebruikersinterface, Disk Operating
System)
 “cmd” (= command) of “powershell”
 Windows subsystem for Linux (WSL)
o MAC OSX
 “terminal
o Secure shell
 Server in de cloud Meestal
 Geen user interface
 Secure shell gebruiken om verbinding te maken




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