Software I: Utilities and Internals

1. Software I: Utilities and Internals Lecture 1 – UNIX for Beginners * Credit to Dr. Robert Siegfried and http://www.upscale.utoronto.ca/GeneralInterest/Harrison/LearnLinux/ by David M.

2. What is UNIX? • UNIX is a time-sharing operating system with user-chosen shells (user interfaces) and one kernel (operating system core, which allocates and control resources such as CPU time, memory and I/O devices). • UNIX includes: • kernel • tools, including compilers, editors, etc. • shell, which includes its own programming language

3. Unix OS Layers Microsoft, Corporation,. Unix Application Migration Guide (Patterns & Practices) Apr 2, 2003

4. Unix Philosophy • Simplicity – KISS • Focus – one program -> one task • Reusable components – libraries • Filters – transform input to produce output – combine unix programs easily that way • Open file formats – config and data not binary • Flexible – assume others will use it differently than you intended

5. What is LINUX? • Linux is an open-source operating system, indirectly based on the last public release of UNIX. • Linux is available in many different versions and different releases and is also closely associated with the GNU project, and through the GNU project has many tools comparable to those found in a UNIX distribution. • GNU – open license (though read details); collaborative project; www.gnu.org

6. GNU Project software for Linux • GCC: The GNU Compiler for C • G++: The GNU Compiler for C++ • GDB: A source code-level debugger • GNU Make: compilation instructions • Bash: A command shell • GNU Emacs: An editor • Linux is the kernel, and you add in projects to make a complete Linux Installation

7. History of UNIX • AT&T Bell Labs (1969) • one of the first time-sharing operating systems. • It was originally developed on a DEC PDP-7 and later redeveloped on a DEC PDP-11 in C, • the first OS written in a high-level language. • popular at colleges and universities and later in the financial industry. • Standards: POSIX (portable Operating System Interface Specs) by IEEE - 1988 • The Single UNIX Specification by The Open Group

8. History of Linux • Andrew Tanenbaum developed MINIX from the last public distribution of UNIX for use with his operating Systems textbook. 1987 • When version 2 of MINIX was released, it was not well adapted for 32-bit processors. This inspired Linus Torsvald to begin work on what became Linux. 1991 • Torsvald welcomed suggestions; this gave way to the community approach to software development that became a hallmark of Linux. • Kernel should contain only freely distributable code

9. Logging In motd (message of the day) doesn't appear when you type login as: pepper pepper@panther.adelphi.edu's password: Last login: Sat Aug 30 21:51:58 2014 from pool-1 Welcome to Panther! If you experience problems or have questions, please contact the IT Help Desk at (516) 877-3340, email support@adelphi.edu, or visit us in the Information Commons on the Second Floor of Swirbul Library. ** Reminder: Your Website is http://home.adelphi.edu/~pe16132 PEPPER@panther:~$ prompt

10. Where are you? • Home • cd ~ or just cd • Present working directory • pwd • What do you have • ls • Moving around directories • cd directory • cd ..

11. Commands to Try Case Sensitivity • date – gives date and time • who – tells you who is on the system and connected to what terminal • who am i – tells you who you are and to what terminal you are connected • whoami – tells you who you are • w – displays what the system users are doing

12. UNIX and Terminals • Unix is full duplex – communications between computer and terminal goes in both directions simultaneously and the computer controls terminal display, using a process called echo. • Example echo hi there hi there (turn echo off with stty –echo and back on with stty echo)

13. stty • UNIX gives the user a way of adjusting terminal settings • stty– set terminal – change and print terminal line settings. • Example PEPPER@panther:~$ stty -a speed 38400 baud; rows 24; columns 80; line = 0; intr = ^C; quit = ^\; erase = ^?; kill = ^U; eof = ^D; eol = <undef>; eol2 = <undef>; swtch = <undef>; … …

14. Standard Codes

15. Try one Standard Code • ^s to stop • Type why don’t I see this • ^q to resume • Type a bit more without pressing enter • Press ^u to erase

16. Stopping A Program • Programs can be stopped by pressing the Break, usually the ^c. • ^z stops a program temporarily. • You can restart it by listing jobs with jobs . • You can bring it to the foreground using fg %1 • ^d indicates end of file. • In your shell, it exits, logging you off • After cat command it stops input mode

17. Logging Out • You can log out by typing logout or exit. If you use the wrong one, the system will let you know. • You can logout by simply typing ^d.

18. Online manual • Most UNIX (and Linux) systems have an online manual that can be accessed by typing: man commandname • Example man who – shows the manual page on who man man– shows the manual page on man (g to top, G to bottom, /<search>, space to get the next page)

19. Info manual • Same information as man but with navigation • See tutorial with ctrl + H and exit that with l • Place cursor and enter to reach section • [ to return

20. Files and File-Oriented Commands • A great deal of work on the system involves files (data moving into or out of the computer), which makes file-oriented commands particularly important. • File commands include: • vi, ex, ed, emacs – file editors • cat, more, pr – printing and display commands • mv, cp, rm – file manipulation commands • grep, sort, diff, tail - filters

21. Create a file using cat • cat concatenates one or more files • Can add file content • Syntax: • cat > filename to create • Lines in the file • Ctrl d to end cat > hello Hi there I am here Ctrl d

22. Append to a file • > sends output to a new file • creates • Overwrites • >> adds to the end • Creates • Appends cat >> hello Put this at the end Ctrl d

23. Text editors • There are 4 text editors that we will concern ourselves with: • ed – the original line-oriented editor • ex – the extended line-oriented editor • vi – visual editor (screen-oriented) - emacs – rich visual editor

24. A Sample ed Session Start the ED editor: ed [filename] Add mode: a Write: w End/Quit: q $ed a add text … type lots of stuff … . ends adding text w junk write text to a file called junk 39 number of characters saved q quit

25. Changing A File Print current line: p Print all lines: 1,$p start at 1, end at last line [SIEGFRIE@panther ~]$ ed junk junk: No such file or directory a To be or not to be . a That is the question . p That is the question 1,$p To be or not to be That is the question

26. Changing A File (continued) Substitute: s/original/new s/the/The/ 1,$p To be or not to be That is The question w 40 q [SIEGFRIE@panther ~]$

27. ls – Listing Files [SIEGFRIE@panther bbb]$ ls junk temp [SIEGFRIE@panther bbb]$ ls -l total 8 -rw-r--r-- 1 SIEGFRIE users 40 Jun 9 16:49 junk -rw-r--r-- 1 SIEGFRIE users 40 Jun 9 17:03 temp [SIEGFRIE@panther bbb]$ ls -t temp junk [SIEGFRIE@panther bbb]$ ls -l -t total 8 -rw-r--r-- 1 SIEGFRIE users 40 Jun 9 17:03 temp -rw-r--r-- 1 SIEGFRIE users 40 Jun 9 16:49 junk [SIEGFRIE@panther bbb]$ ls -lt total 8 -rw-r--r-- 1 SIEGFRIE users 40 Jun 9 17:03 temp -rw-r--r-- 1 SIEGFRIE users 40 Jun 9 16:49 junk [SIEGFRIE@panther bbb]$ ls * - all contents below

28. ls– l • ls –l – provides a long listing of the files [SIEGFRIE@panther bbb]$ ls –l long listing total 8 -rw-r--r-- 1 SIEGFRIE users 40 Jun 9 16:49 junk -rw-r--r-- 1 SIEGFRIE users 40 Jun 9 17:03 temp date & time of last modification owner's group # of links to file Permissions owner file name # of bytes in file

29. Permission -rw-r--r-- regular file Owner's group has read but not write nor execute permission Owner has read and write but not execute permission The rest of the world has read but not write nor execute permission

30. Displaying File Content • cat - displays multiple files in order • more – displays one page at a time • Space for next page • b to back up (not classic) • q to quit • / to search • G to bottom and g to top • less – similar to more • pr – display as pages for a printer

31. mv, cp and rm • mv – move (or rename) a file • mv origname1 newname • mv origname2 ../newplace/newname • mv origname3 folder1/ • mv origname4 ../ • cp – copy a file • cp file1 file2 • rm – remove (or delete) a file • rm file1 • rm * - deletes everything in the directory! • rm –rf folder1 – deletes folder and its contents

32. Rules Governing File Names • Much older systems may limit names to 14 characters. • UNIX is case-sensitive; junk, Junk and JUNK are three different files. • File names should not (but unfortunately can) include unprintable characters (like escape characters) or characters with special meanings. • E.g., how would you print the file –t?

33. Name completion • Put in the first few characters • Tab • Fills if only one choice • If not unique, tab again for choices

34. Command History • All commands from this shell and then prior fully exited shell • Up and Down keys to see them • Enter to execute • Or Edit with left and right arrow keys • history command • See command number • !command number to execute it

35. Quick VI introduction • Create a file with vi filename • See contents • Type contents (starting in insert mode) • Save: escape :wq • Means escape into command mode • W for write to the filename given • Q for quit

36. Mid PPT summary • Signon • Entry of commands • Terminal settings • Standard control characters • Creating files • Displaying files • Copy and Move files

37. Exercise • Start putty and enter panther.adelphi.edu then open • Exercises 1-3 • Use ls not lc • Use cat, ed and vi to create the files when asked

38. A Few Helpful File Processing Commands • There are several file processing commands that will become useful:

39. grep Search inside a file [SIEGFRIE@panther bbb]$ grep fleas poem Great fleas have little fleas And little fleas have lesser fleas, And the great fleas themselves, in turn, have greater fleas to go on; [SIEGFRIE@panther bbb]$ grep -v fleas poem upon their backs to bite 'em and so on ad infinitum. While these again have greater still, and great still and so on.

40. diff Line by line difference [SIEGFRIE@panther bbb]$ diff poem newpoem 2c2 < upon their backs to bite 'em --- > upon their backs to bite them 4c4 < and so on ad infinitum. --- > and so til ad infinitum. [SIEGFRIE@panther bbb]$

41. Command Summary

42. Command Summary

43. Directories • The system knows how to distinguish between different files with the same name by recognizing that they are listed in different directories. • Each user has his/her own directory, which can be divided into subdirectories by the user. • You can use the cd (change directory) command to switch between different directories and pwd (print working directory) to display the current directory being used.

44. Directory Movement • Move up one directory • cd .. (up one) • cd ../anotherdirectory (get to parallel dir) • cd ../../yetanotherdir (up 2 and down one) • cd directory (goes down) • cd /bin (absolute path) • Move to home • cd ~ • Where are you? • pwd

45. A Sample File System / • /bin : binaries, programs used in booting • /usr/bin: user binaries, standard programs available to users • /usr/local/bin: local binaries, programs specific to installation dev bin etc usr tmp unix boot you mike paul mary junk junk temp junk data

46. Managing Directories • mkdir dirname • Makes a directory inside your present working directory • rmdir dirname • Delete an empty directory • Use file commands to rename or copy dirs • Rename a directory: mv olddir newdir • Copy a directory: cp olddir newdir

47. The Shell • The shell is another name for the command interpreter, which runs all the commands that we type in a session on a UNIX (or Linux) system. • It provides 3 benefits: • File name shorthands - a whole bunch of files specified using wild card characters, can be specified at one. • Input-output redirection – a file can replace either keyboard or screen or both. • You can personalize your environment.

48. Using * * Expands to all matching files • pr * - displays all the files in print format. • rm * - deletes all files in current directory. (do not do this) • rm *.sav – deletes all files ending with .sav • ls * - displays all files and folder contents except . And .. • ls.* - displays all files and folder contents above and all below you

49. Metacharacters – An Example [SIEGFRIE@panther junk]$ echo * cookie temp See all files except hidden that * suppresses [SIEGFRIE@panther junk]$ echo .* . .. .mybad Just the hidden files PEPPER@panther:~/271/tobetar$ ls * junk99 linkToMenu5.c menu4.c menu5.c insidedir: afileinsidedir afileinsidedir2 All files inside dir and subdir PEPPER@panther:~/271/tobetar$ ls .* .: insidedir junk99 linkToMenu5.c menu4.c menu5.c ..: alphavowels dict.txt All files inside the . Files of . And .. – so all above

50. [ ] • [ ] matches a single occurrence of one of the characters in the brackets. • pr ch[12346789] prints every whole chapter except 5. • pr ch[1-46-9] prints every whole chapter except 5. • rm temp[a-z] – deletes tempa, tempb, …, tempz if they exist.