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UNIX

UNIX. What is UNIX? Getting Connected Basic UNIX Commands Help! Working with Directories Running Programs Editors The Shell Exercise. What is UNIX?. Multi-Tasking O/S Multi-User O/S Available on a range of Computers. Which UNIX?. SunOS Sun Microsystems IRIX Silicon Graphics

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UNIX

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  1. UNIX • What is UNIX? • Getting Connected • Basic UNIX Commands • Help! • Working with Directories • Running Programs • Editors • The Shell • Exercise

  2. What is UNIX? • Multi-Tasking O/S • Multi-User O/S • Available on a range of Computers

  3. Which UNIX? • SunOS Sun Microsystems • IRIX Silicon Graphics • HP-UX Hewlett Packard • Linux For IBM PC compatibles

  4. UNIX Internals (Simplified) • Kernel • System Internals • Shell • Command Interpreter • Programming language • File System • Process Management

  5. UNIX Shells • C-Shell • Bourne Shell • Korn Shell • T-Shell • bash

  6. Terminal Emulation Software • DOS Based Telnet • Windows 9x/NT/XP, Telnet and X Windows • Networked Macintosh, Telnet

  7. Graphical UNIX via Exceed • X Concepts • Using the Exceed Software • Starting the Common Desktop Environment

  8. Basic X Concepts • X Server runs on local machine • PC Exceed • UNIX Workstation Included in OS • Apple Mac Exodus • X Client runs on remote machine • Graphical Application • xterm • file manager • Modelling Package

  9. Basic X Concepts

  10. The Common Desktop Environment

  11. Starting CDE- XSession Options

  12. Setting the XServer Options

  13. Using Exceed :XTerm

  14. Using Exceed to Start an XClient

  15. Rules of Engagement • UNIX is case sensitive • Commands are in lower case • Backspace and Del Keys correct typing errors • Ctrl U clears the command line • Ctrl C Aborts a program or command • Do Not use the arrow keys

  16. Filenames • Filenames can comprise: a-z, A-Z alphabetic characters 0-9 digits .-_+ special characters mon+tue_01.06-03-96 • Wildcards * means any character or sequence of characters

  17. Format of UNIX commands • command [option ...] [filename ...] eg: ls ls -l tutorial more tutorial

  18. List Directory • ls list directory • ls -l list directory in long format • ls -a list all (inc. hidden) files -rw------ l course01 57 Oct 18 11:05 hello.c Access Permissions Number ofbytes in file Date and time last modified

  19. Displaying a Text File • morefilename Spacebar next screenful Enter next line q quit ? list commands

  20. Copy, Rename and Remove • Copy a file cp oldfile newfile • Rename a file mv oldname newname • Remove a file rm afile

  21. Searching Files • grep string file string = word or phrase file = file or list of files

  22. Redirection • The output of a command usually goes to the screen • Redirect the output to a file using ‘>‘ ls -l > dirlist

  23. Piping • Feeding the output of one command into the input of another command • The symbol ‘|’ is called a pipe command | command • eg: ls -al | more ls -la | grep Nov

  24. Manual Pages • man command • man - k topic • man - k topic | more

  25. Example Manual Pages • Synopsis mv [ - ] [- fi] filename1 filename2 optional options cp [ - ip] filename1 filename2 cp [ - iprR ] filename ... directory rm [ - ] [ - fir ] filename ... rmdir directory

  26. Directory Structure / (root) home1 usr me cs ph cs4un1 cs4un2 /home1/cs/cs4un1

  27. Directories • pwd print working directory • cd change directory cd move to home directory cd .. move up one level cd mydir move into a subdirectory cd /var/adm move to an absolute directory

  28. Managing Filestore • Each user has an allocation of filestore (Disk Space) • Monitor filestore usage with the ‘quota’ command EG: quota -v Disk quotas for username (uid 20002) Filesystem usage quota limit timeleft files quota limit timeleft /stoat-g 20 2000 4000 13 1000 1500 • The quota value can be exceeded for 7 days quota < usage < limit for 7 days • The limit value can not be exceeded usage < limit always • If usage > quota for 7 days account is expired and files can not be created

  29. Running programs • Two modes of operation foreground and background • Foreground Interact with program via keyboard/screen • Background No connection with keyboard/screen Submit to backbround by Appending ‘&’ EG: myprog >& myfile & The symbols ‘>&’ redirect output and any errors to the file myfile Another method of submitting programs to the background is via a batch processing system, such as Sun Grid Engine (as used on Titania)

  30. Foreground Program Control • Kill a program Ctrl C • Stop a program Ctrl Z Note a stopped program still exists in the system

  31. Program control within current shell • jobs Lists jobs (programs) • bg %job_id Place a job in the background • fg %job_id Return a job to the foreground • stop %job_id Stop a job • kill %job_id Kill a job jobs [1] + Running time.sh > out stop %1 [1] + Stopped (signal) time.sh > out bg %1 [1] + time.sh > out & kill %1 Terminated

  32. Program control using ‘ps’ and ‘kill’ • ps Report process status ps -f -u username UID PID PPID C STIME TTY TIME CMD username 24816 24585 0 16:23:04 pts/50 0:00 sleep 2 username 20169 19956 0 16:05:45 pts/50 0:01 -csh username 24585 20169 0 16:35:07 pts/50 0:00 /bin/sh time.sh • kill Terminate process • Find its process ID (PID) using the ps command • Kill the process using the kill command kill 24585 • Sometimes kill on its own does not work so try kill -KILL 24585

  33. Programe Control using top • top is a separate utility and not part of the OS top -Uusername • k kill program (process) k PID, k -KILL PID • h help • q quit top

  34. Vi Text Editor • Very powerful • Available on all versions of UNIX • No in-built help • Man page gives detailed help • Vi has three modes • Command • Text entry • Last line

  35. Editors • Dtpad • nedit • vi • emacs

  36. Desktop Note Pad Editor

  37. T-Shell - Filename Completion • Complete a partially typed filename • Operation • Type enough characters to uniquely identify the name • Press the ‘Tab’ key (for C – shell use ‘Esc’ key) • If the response is a ‘bleep’ press Ctrl-d to list possible matches • Setup • Add the following to your .cshrc file • set filec

  38. T-Shell -Repeating Previous Commands • Operation • history List previous commands • !! re-run last command • !n re-run the nth command • !str last command starting with str eg: !vi • Setup • Add the following to your .cshrc file • set history=40

  39. T-Shell - Command Aliasing • Definitions • alias ll ' ls -lF ' • alias h ' history 24 ' • alias dir ' ls ' • Setup • Add alias definitions to your .cshrc file

  40. The Secure shell protocol • SSH is a new method of communications over the Internet that encrypts data end-to-end • Replaces telnet, ftp, rsh and rcp • Components • Secure shell ssh • Secure ftp sftp • Secure copy scp

  41. Secure Shell • Program to log into another computer over a network • Execute commands on a remote machine • Move files from one machine to another • Provides strong authentication and secure communications over insecure channels. • Intended as a replacement for rlogin, rsh, rcp, and rdist.

  42. ssh • You only need the SSH client. The server is unnecessary, unless you wish to connect back to your home machine via the Internet using SSH. • Connecting to a WRG nodessh -l wrsmg maxima.leeds.ac.uk • To use X-windows add the "-X" flag • SSH will then carry Xwindows traffic over the Internet to connect • Range of options for changing ports, specifying authentication files, encryption algorithms etc…. • Use man ssh for help with options

  43. Secure ftp (sftp) • Establishes an FTP-style file transfer session between the Unix systems • sftp command always used in the form: sftpuser@server • e.g.from titania sftp wrsmg@maxima.leeds.ac.uk

  44. Transferring Files Using sftp From the SFTP prompt (sftp>) can do the following: • get command to retrieve a file from the remote Unix server. • get test.txt • put command to transfer a file from your Unix system to the remote Unix system you are connected to. • put file2.txt

  45. Navigating file systems using sftp From the SFTP prompt (sftp>) can do the following: • ls command to display the contents of a directory on the remote Unix system you are connected to. • ls /home/user. Will display the contents of the directory /home/user on the remote Unix system. • cd and lcd commands change current remote directory, or current local directory. • e.g. cd /home/user. Will change the current remote directory to /home/user.

  46. Summary of sftp commands 1 • mget Retrieve multiple files from server • Mput Transfer multiple files to server • pwd Display remote working directory • quit or exit Quit sftp • rename oldpath newpath Rename remote file • rmdir path Remove remote directory • rm path Delete remote file • version Show SFTP version • ? Synonym for help

  47. Summary Listing of SFTP commands 2 ascii Use text transfer mode help Display the help text image Use binary transfer mode lls [ls-options [path]] Display local directory listing lmkdir path Create local directory ls [path] Display remote directory listing mkdir path Create remote directory put local-path [remote-path] Upload file

  48. Secure copy - scp • Using SCPFast, easy method to copy single files from your Unix system to a remote Unix system.

  49. Retrieving a file using SCP • To retrieve a file from a remote Unix system, the syntax is: scp username@server:file local-file • username= username on the remote system • server= the name of the remote Unix system • file= the file to retrieve from the remote system • local-file= the location you wish to save the file to on your local Unix system

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