Dev-day Linux

Gnu linux history and simple shellscripts

Transcript

1. Tarcisio Coutinho 16 Nov 2012 Dev-day Linux - 101
2. Timeline • 1965 :: MULTICS :: MTI, Bell Labs (AT&T) e General Eletric • 1969 :: Ken Thompson :: Unics (Assembly) • 1971 :: Ken Thompson :: Rewrites the system on B language (to solve portability problems) • 1973 :: Thompson and Denis Richie :: C programming language • 1974 :: UNIX \o/ • 1983 :: AT&T closes the UNIX's source code • 1983 :: Andrew Tanenbaum :: MINIX • 1984 :: Richard Stallman :: GNU (GCC, Emacs) • 1991 :: Linux Torvalds :: GNU/Linux
3. GNU/Linux Distribution Timeline http://futurist.se/gldt/
4. GNU/Linux
5. GNU/Linux Structure
6. Shell
7. What is Shell? • Provides the command prompt and to interpret commands • Provides user interface for the OS and Kernel
8. Shell implementations • bash (bourne again shell :: GNU implementation) • ash (Almquist Shell :: BSD) • csh (C shell :: BSD) • tcsh (tee-shell) • sh (Stephen Bourne) • ksh (Korn shell)
9. Shell Variable Basics • bash maintains a set of shell variables ◦ PS1 :: Prompt String 1 :: Default interaction ◦ PS2 :: Prompt String 1 :: Continuation interactive prompt ◦ PATH :: contains a list of all the directories that hold commands or other programs you are likely to execute • bash variables are untyped
10. Export Variables • When a variable is exported to the environment, it is passed into the environment of all child processes • let's go to the terminal ◦ REDU="Redu Tech" ▪ conventionally uppercase ◦ echo $REDU or echo ${REDU} ▪ $ prefix to interpret a shell var ◦ echo "echo \$REDU" | bash
11. Fun with PS1 :: Information • \u - Username • \h - Hostname • \w - Full path of the current woking directory
12. export PS1="\u@\h \w"
13. export PS1="\u@\redu: \w "
14. Fun with PS1 :: Colors • \e[ :: indicates the beginning of color • x;ym :: indicates color code • \e[m :: indicates end of color prompt White 1;37 Green 1;32 Cyan 1;36 Yellow 1;33
15. PS1="\e[01;32m\u\e[m@\redu: \w "
16. PS1="\e[01;32m\u\e[m\e[1;37m@\e [mredu: \w "
17. PS1="\e[01;32m\u\e[m\e[1;37m@\e [m\e[1;36mredu:\e[m \w "
18. PS1="\e[01;32m\u\e[m\e[1;37m@\e [m\e[1;36mredu:\e[m\e[1;33m\w\e [m "
19. Streams, Pipes and Redirects
20. Streams • Everything is a file. ◦ a program reading from the terminal’s device file will receive characters typed at the keyboard • When a program is launched, it is automatically provided with three file descriptors ◦ Standard input (abbreviated stdin) :: 0 ◦ Standard output (abbreviated stdout) :: 1 ◦ Standard error (abbreviated stderr) :: 2 • The standard input is different than parameters
21. Pipes and Redirects • Pipes | ◦ provides communication inter-process ▪ tie the output of one program to the input of another ▪ e.g. echo "echo 'Hello Redu'" | bash • Redirection ◦ allows you to manage the origin of input streams and the destination of output streams ▪ > :: Redirection operator ▪ >> :: Append operator ▪ < :: Receive stdin from file
22. GNU and Unix Commands
23. Tricks • cd - :: go to the recent directory ◦ Works with git branches ▪ git checkout - • !! :: call most recent command ◦ bang-bang • $( ) :: Command substitution or sub-shell ◦ cd $(pwd)/..
24. GNU and Unix sed & awk
25. Sed • Stream based processing text editor echo "sed tutorial. sed is a powerful text editor" | sed 's/sed/awk/' echo "sed tutorial. sed is a powerful text editor" | sed 's/sed/awk/g' echo "sed tutorial. sed is a powerful text editor" | sed 's/sed/awk/2g'
26. Sed echo "line without numbers \nline with numbers: 1 2 3 " | sed -r 's/[0-9]+/X/g' echo "line without numbers \nline with numbers: 1 2 3 " | sed -rn 's/[0-9]+/X/g' echo "line without numbers \nline with numbers: 1 2 3 " | sed -rn 's/[0-9]+/X/gp'
27. Sed • Delete lines ◦ sed '1,2-3 d' [FILE] ◦ sed '/[pattern]/d [FILE] ◦ sed -i '1 d' [FILE] • Add lines ◦ sed '/[pattern]/ i [text]' [FILE] ◦ sed '/[pattern]/ a [text]' [FILE] ◦ sed "1s/^/[text]" [FILE]
28. Awk • AWK ◦ processing text programming language ▪ column based awk -F [pattern] '{ [CMD] }' $n -> variable from split by pattern match ls -l | awk -F ' ' '{print $0}'
29. Quests
30. Fun with Seds • Parse rails logs ◦ Request count development.log ◦ Top 10 most slow compound log job grep awk head wc uniq sort tail sed 'N;' sed cut nl expand tr
31. Dev-day Linux - 101