C2110 UNIX and programming Lesson 4 -1C2110
UNIX and programming
Petr Kulhanek
kulhanek@chemi.muni.cz
National Center for Biomolecular Research, Faculty of Science
Masaryk University, Kamenice 5, CZ-62500 Brno
Lesson 4
PS / 2020 Distance form of teaching: Rev2
C2110 UNIX and programming Lesson 4 -2-
Revision
➢ Processor, Process
➢ Running Programs
➢ Redirection
➢ Pipes
C2110 UNIX and programming Lesson 4 -3Internal
Scheme of a Computer
north
bridge
north
bridge
south
bridge
south
bridgeUSB
mouse,
keyboard
real time
clock
SATA controllers
hard drives
BIOS
graphics
system
memory
memory controller
peripherals with fast access
via PCI Express
Network
(ethernet)
sound
PCI bus
computational cores (CPU core)
processor
number of CPU cores > 1
= SMP computer
Operating system ensures running of
programs (processes) on the processors
and optimal use of other resources
(memory, disk capacity). Multitasking
technique is used in management of
processes.
C2110 UNIX and programming Lesson 4 -4Starting
processes
the name of the program or script is
given including the path (absolute or
relative)
User programs and scripts:
$ ./my_script
$ ~/bin/my_application
Standard commands and programs:
$ ls Standard commands and programs are in
the path defined by the PATH variable
Running applications in the foreground
Running applications in the background
$ gimp &
at the end (after arguments and redirects) of the
statement we type an ampersand
$ gimp
processes running in the foreground block the
terminal because they use its standard input and
output
processes running in the background do not
block the terminal
usable for both standard and user
programs
C2110 UNIX and programming Lesson 4 -5-
Redirection
Input-output currents can be redirected to use files instead of the keyboard or screen.
$ program < input.txt > output.txt 2> error.txt
process
(command, program)standard input stream
(keyboard)
standard output stream
(terminal screen)
standard error stream
(terminal screen)
input.txt
output.txt error.txt
C2110 UNIX and programming Lesson 4 -6-
Pipes
Pipes serve to combine the standard output of one process with the standard input of
another process.
process 1 process 2
input
output | input
output
error output
error output
$ command_1 | command_2
Usage:
Redirection and pipes can be combined.
C2110 UNIX and programming Lesson 4 -7Next
Subject
➢ Basic Work with Linux
C2110 UNIX and programming Lesson 4 -8-
Content
➢ Linux as a Desktop Environment
• GNOME
• Terminals
• Standard and scientific-technical applications
➢ File System
• Quotas
• Disk device
• Symbolic links
➢ Text Editors
• vi, vim, nano
• gedit, kwrite, kate