“Awesomeness put to mundane use”
TV Tropes on Mundane Utility
Slide 3
Slide 3 text
Unix Shell Userland
Kernel
Hardware
Slide 4
Slide 4 text
How did we get here…
Slide 5
Slide 5 text
How did we get here…
firmware
Slide 6
Slide 6 text
How did we get here…
firmware
boot loader
Slide 7
Slide 7 text
How did we get here…
firmware
boot loader
kernel
Slide 8
Slide 8 text
How did we get here…
firmware
boot loader
kernel
init
Slide 9
Slide 9 text
No content
Slide 10
Slide 10 text
How did we get here…
firmware
boot loader
kernel
init
Slide 11
Slide 11 text
How did we get here…
firmware
boot loader
kernel
init
getty
note this is just one
example sequence at
this point onwards
Slide 12
Slide 12 text
How did we get here…
firmware
boot loader
kernel
init
getty
login
Slide 13
Slide 13 text
How did we get here…
firmware
boot loader
kernel
init
getty
login
shell
Slide 14
Slide 14 text
How did we get here…
firmware
boot loader
kernel
init
getty
login
shell
ls
Slide 15
Slide 15 text
A shell…
Slide 16
Slide 16 text
why?
A shell…
Slide 17
Slide 17 text
No content
Slide 18
Slide 18 text
A shell…
Line Editing
Command Parsing
Command Expansion
Process Management
Builtins
Slide 19
Slide 19 text
line editing…
q w e r t y
Slide 20
Slide 20 text
command parsing…
Slide 21
Slide 21 text
command parsing…
::= lists EOF
| EOF
::= list
| list list
::= list
| list pipeline
| list pipeline
::= pipeline
| pipeline command
::= word
| command word
::= ;
::= &&
::= ||
::= |
::= …
Slide 22
Slide 22 text
command parsing…
character input
Slide 23
Slide 23 text
command parsing…
lexer
Slide 24
Slide 24 text
command parsing…
token stream
Slide 25
Slide 25 text
command parsing…
parser
Slide 26
Slide 26 text
command parsing…
program
Slide 27
Slide 27 text
lexing words…
word
soft hard unquoted
text variable text
variable
Slide 28
Slide 28 text
process management…
Slide 29
Slide 29 text
ls | sort | uniq
process management…
Slide 30
Slide 30 text
process management…
fork()
ls | sort | uniq
uniq
sort
ls
xsh
xsh
xsh
xsh
Slide 31
Slide 31 text
fork() fork()
ls | sort | uniq
uniq
sort
ls
xsh
xsh
xsh
xsh
process management…
Slide 32
Slide 32 text
fork() fork() exec()
ls | sort | uniq
uniq
sort
ls
xsh
xsh
xsh
xsh
process management…
Slide 33
Slide 33 text
fork() fork()
fork()
exec()
ls | sort | uniq
uniq
sort
ls
xsh
xsh
xsh
xsh
process management…
Slide 34
Slide 34 text
fork() fork()
fork()
exec()
exec()
ls | sort | uniq
uniq
sort
ls
xsh
xsh
xsh
xsh
process management…
Slide 35
Slide 35 text
fork() fork()
fork()
exec()
exec()
exec()
ls | sort | uniq
uniq
sort
ls
xsh
xsh
xsh
xsh
process management…
Slide 36
Slide 36 text
ls | sort | uniq
xsh xsh xsh xsh
uniq sort ls
fork()
process management…
Slide 37
Slide 37 text
ls | sort | uniq
xsh xsh xsh xsh
uniq sort ls
fork() fork()
process management…
Slide 38
Slide 38 text
ls | sort | uniq
xsh xsh xsh xsh
uniq sort ls
fork() fork() fork()
process management…
Slide 39
Slide 39 text
ls | sort | uniq
xsh xsh xsh xsh
uniq sort ls
fork() fork() fork()
exec()
process management…
Slide 40
Slide 40 text
ls | sort | uniq
xsh xsh xsh xsh
uniq sort ls
fork() fork() fork()
exec() exec()
process management…
Slide 41
Slide 41 text
ls | sort | uniq
xsh xsh xsh xsh
uniq sort ls
fork() fork() fork()
exec() exec() exec()
process management…
Slide 42
Slide 42 text
ls | sort | uniq
fork()
xsh
xsh xsh xsh
ls
sort
uniq
process management…
Slide 43
Slide 43 text
ls | sort | uniq
fork()
exec()
xsh
xsh xsh xsh
ls
sort
uniq
process management…
Slide 44
Slide 44 text
ls | sort | uniq
fork()
fork()
exec()
xsh
xsh xsh xsh
ls
sort
uniq
process management…
Slide 45
Slide 45 text
ls | sort | uniq
fork()
fork()
exec() exec()
xsh
xsh xsh xsh
ls
sort
uniq
process management…
Slide 46
Slide 46 text
ls | sort | uniq
fork() fork()
fork()
exec() exec()
xsh
xsh xsh xsh
ls
sort
uniq
process management…
Slide 47
Slide 47 text
ls | sort | uniq
fork() fork()
fork()
exec() exec() exec()
xsh
xsh xsh xsh
ls
sort
uniq
process management…