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Quick start bash script

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Simon Su
Simon Su

This document provides an introduction to shell scripting using Bash. It outlines different shell types and their features. It then covers basic Bash scripting concepts like environment variables, file redirection, command substitution and parameters. The document demonstrates basic Bash commands like alias, if/then, loops, functions and find/awk/sed/xargs. It concludes with an overview of vi text editor commands for navigation, editing, splitting windows and setting options.

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Quick Start - Bash Script Simon Su
● Not a linux/unix guide ... ● Talk something basic about programming shell script ... ○ Basic concepts ○ Basic commands ○ Vi Outline
Shell Scripts ● sh ● bash ● ksh ● csh ● zsh sh csh ksh bash tcsh zsh rc es Job control N Y Y Y Y Y N N Aliases N Y Y Y Y Y N N Shell functions Y(1) N Y Y N Y Y Y "Sensible" Input/Output redirection Y N Y Y N Y Y Y Directory stack N Y Y Y Y Y F F Command history N Y Y Y Y Y L L Command line editing N N Y Y Y Y L L Vi Command line editing N N Y Y Y(3) Y L L Emacs Command line editing N N Y Y Y Y L L Rebindable Command line editing N N N Y Y Y L L User name look up N Y Y Y Y Y L L Login/Logout watching N N N N Y Y F F Filename completion N Y(1) Y Y Y Y L L Username completion N Y(2) Y Y Y Y L L Hostname completion N Y(2) Y Y Y Y L L History completion N N N Y Y Y L L Fully programmable Completion N N N N Y Y N N Mh Mailbox completion N N N N(4) N(6) N(6) N N Co Processes N N Y N N Y N N Builtin artithmetic evaluation N Y Y Y Y Y N N Can follow symbolic links invisibly N N Y Y Y Y N N Periodic command execution N N N N Y Y N N Custom Prompt (easily) N N Y Y Y Y Y Y Sun Keyboard Hack N N N N N Y N N Spelling Correction N N N N Y Y N N Process Substitution N N N Y(2) N Y Y Y Underlying Syntax sh csh sh sh csh sh rc r Freely Available N N N(5) Y Y Y Y Y Checks Mailbox N Y Y Y Y Y F F Tty Sanity Checking N N N N Y Y N N Can cope with large argument lists Y N Y Y Y Y Y Y Has non-interactive startup file N Y Y(7) Y(7) Y Y N N Has non-login startup file N Y Y(7) Y Y Y N N Can avoid user startup files N Y N Y N Y Y Y Can specify startup file N N Y Y N N N N Low level command redefinition N N N N N N N Y Has anonymous functions N N N N N N Y Y List Variables N Y Y N Y Y Y Y Full signal trap handling Y N Y Y N Y Y Y File no clobber ability N Y Y Y Y Y N F Local variables N N Y Y N Y Y Y Lexically scoped variables N N N N N N N Y Exceptions N N N N N N N Y
Basic Concept - .bashrc / .bash_profile / .bash_history ● .bashrc ● .bash_profile ● .bash_history
Basic Concept - man page ● man [commands] ex: man bash
Basic Concept - Declare & Comment ● #!/bin/bash ● #comments...
Basic Concept - Environment ● export KEY=VALUE
Basic Concept - source ● . [script file] ● source [script file]
Basic Concept - “|” ● ps -ef | grep root ● ps -ef | cat > /tmp/ps.log ● ps -ef | grep httpd | awk '{print $2}'
Basic Concept - “<” & “>” & “>>” ● mysql -uroot -p < test.sql ● ps -ef > ps.log ● bash [file] > /dev/null 2>&1 ● ps -ef >> ps.log
Basic Concept - `[commands]` ● kill -9 `ps -ef | grep httpd | awk ‘{print $2}’` ● tail -f `svcs -L apache`
Basic Concept - ‘’ & “”
Basic Concept - & and && ● bash [file] & ● bash [file1] && bash [file2]
Basic Concept - bash execution ● #!/bin/bash ● ./[file] ● bash [file] ● bash -x [file]
Basic Concept - Parameter input ● Input: bash [file] [parameter 1] [parameter 2] … ● Receive: $1, $2....
Basic Concept - Parameters of Bash ● $# ● $@ ● $* ● $?
● alias ll=”ls -l” Basic Commands - alias
Basic Commands - bg / fg Process lock screen.. ctrl + z (process stop and screen return) bg (process keep running) fg (screen back to process)
Basic Commands - background proc ● bash [script file] & ● nohup bash [script file] & ● nohup bash [script file] > /dev/null 2>&1 &
if …. then … elseif … fi export i=5; if [ $i -gt 5 ] ; then echo $i; fi if [ $i -eq 5 ] ; then echo $i; fi if Expression then Commands elif Expression then Commands else Commands fi if (Expression) then Commands elif (Expression) then Commands else Commands fi if [ Expression ]; then Commands elif [ Expression ]; then Commands else Commands fi
for / while / until loop for name in { 1..10 } do …. done for VariableName in List do Commands done while [Expression] do Commands done until [ Expression ] do Commands done
function helloworld(){ echo hello $1 } helloworld simon
Basic Commands - find ● find [from] -name [pattern] -print ● find [from] -name [pattern] -type f ● find [from] -ctime 3 -print ● find [from] -atime +1 -print -exec ls -l {} ;
Basic Commands - awk ● awk -F "t" '{print $1,$2}' /etc/hosts ● cat /etc/hosts | awk -F "t" '{print $1,$2}'
Basic Commands - sed ● sed 's/old_text/new_text/g' [file] ● sed -i 's/old_text/new_text/g' [file]
Basic Commands - xargs ● ps -ef | grep node | awk '{print $2}' | xargs kill -9
Nice tool - bash_it ● https://github.com/revans/bash-it ● Install: ○ Check a clone of this repo: git clone http://github.com/revans/bash-it.git ~/.bash_it ○ Run ~/.bash_it/install.sh ○ Edit your ~/.bash_profile file in order to customize bash-it.
Vi
Vi - View Mode
Vi - Edit Mode
Vi - Goto line & Search & Replace ● Goto line: :[line number] ● Search: /[key] ● Replace first: %s/[old]/[new] ● Replace all: %s/[old]/[new]/g
Vi - split, vsplit ● :vsp ● :vsp [file] ● :sp ● :s[ [file] ● ctrl+w
Vi - tabedit ● :tabe [file] ● gt ● n gt
Vi - set ● :set nu / :set nonu ● :set paste
Vi - execute command ● :![command]
Vi - ~/.vimrc

More Related Content

Quick start bash script

  • 1. Quick Start - Bash Script Simon Su
  • 2. ● Not a linux/unix guide ... ● Talk something basic about programming shell script ... ○ Basic concepts ○ Basic commands ○ Vi Outline
  • 3. Shell Scripts ● sh ● bash ● ksh ● csh ● zsh sh csh ksh bash tcsh zsh rc es Job control N Y Y Y Y Y N N Aliases N Y Y Y Y Y N N Shell functions Y(1) N Y Y N Y Y Y "Sensible" Input/Output redirection Y N Y Y N Y Y Y Directory stack N Y Y Y Y Y F F Command history N Y Y Y Y Y L L Command line editing N N Y Y Y Y L L Vi Command line editing N N Y Y Y(3) Y L L Emacs Command line editing N N Y Y Y Y L L Rebindable Command line editing N N N Y Y Y L L User name look up N Y Y Y Y Y L L Login/Logout watching N N N N Y Y F F Filename completion N Y(1) Y Y Y Y L L Username completion N Y(2) Y Y Y Y L L Hostname completion N Y(2) Y Y Y Y L L History completion N N N Y Y Y L L Fully programmable Completion N N N N Y Y N N Mh Mailbox completion N N N N(4) N(6) N(6) N N Co Processes N N Y N N Y N N Builtin artithmetic evaluation N Y Y Y Y Y N N Can follow symbolic links invisibly N N Y Y Y Y N N Periodic command execution N N N N Y Y N N Custom Prompt (easily) N N Y Y Y Y Y Y Sun Keyboard Hack N N N N N Y N N Spelling Correction N N N N Y Y N N Process Substitution N N N Y(2) N Y Y Y Underlying Syntax sh csh sh sh csh sh rc r Freely Available N N N(5) Y Y Y Y Y Checks Mailbox N Y Y Y Y Y F F Tty Sanity Checking N N N N Y Y N N Can cope with large argument lists Y N Y Y Y Y Y Y Has non-interactive startup file N Y Y(7) Y(7) Y Y N N Has non-login startup file N Y Y(7) Y Y Y N N Can avoid user startup files N Y N Y N Y Y Y Can specify startup file N N Y Y N N N N Low level command redefinition N N N N N N N Y Has anonymous functions N N N N N N Y Y List Variables N Y Y N Y Y Y Y Full signal trap handling Y N Y Y N Y Y Y File no clobber ability N Y Y Y Y Y N F Local variables N N Y Y N Y Y Y Lexically scoped variables N N N N N N N Y Exceptions N N N N N N N Y
  • 4. Basic Concept - .bashrc / .bash_profile / .bash_history ● .bashrc ● .bash_profile ● .bash_history
  • 5. Basic Concept - man page ● man [commands] ex: man bash
  • 6. Basic Concept - Declare & Comment ● #!/bin/bash ● #comments...
  • 7. Basic Concept - Environment ● export KEY=VALUE
  • 8. Basic Concept - source ● . [script file] ● source [script file]
  • 9. Basic Concept - “|” ● ps -ef | grep root ● ps -ef | cat > /tmp/ps.log ● ps -ef | grep httpd | awk '{print $2}'
  • 10. Basic Concept - “<” & “>” & “>>” ● mysql -uroot -p < test.sql ● ps -ef > ps.log ● bash [file] > /dev/null 2>&1 ● ps -ef >> ps.log
  • 11. Basic Concept - `[commands]` ● kill -9 `ps -ef | grep httpd | awk ‘{print $2}’` ● tail -f `svcs -L apache`
  • 12. Basic Concept - ‘’ & “”
  • 13. Basic Concept - & and && ● bash [file] & ● bash [file1] && bash [file2]
  • 14. Basic Concept - bash execution ● #!/bin/bash ● ./[file] ● bash [file] ● bash -x [file]
  • 15. Basic Concept - Parameter input ● Input: bash [file] [parameter 1] [parameter 2] … ● Receive: $1, $2....
  • 16. Basic Concept - Parameters of Bash ● $# ● $@ ● $* ● $?
  • 17. ● alias ll=”ls -l” Basic Commands - alias
  • 18. Basic Commands - bg / fg Process lock screen.. ctrl + z (process stop and screen return) bg (process keep running) fg (screen back to process)
  • 19. Basic Commands - background proc ● bash [script file] & ● nohup bash [script file] & ● nohup bash [script file] > /dev/null 2>&1 &
  • 20. if …. then … elseif … fi export i=5; if [ $i -gt 5 ] ; then echo $i; fi if [ $i -eq 5 ] ; then echo $i; fi if Expression then Commands elif Expression then Commands else Commands fi if (Expression) then Commands elif (Expression) then Commands else Commands fi if [ Expression ]; then Commands elif [ Expression ]; then Commands else Commands fi
  • 21. for / while / until loop for name in { 1..10 } do …. done for VariableName in List do Commands done while [Expression] do Commands done until [ Expression ] do Commands done
  • 23. Basic Commands - find ● find [from] -name [pattern] -print ● find [from] -name [pattern] -type f ● find [from] -ctime 3 -print ● find [from] -atime +1 -print -exec ls -l {} ;
  • 24. Basic Commands - awk ● awk -F "t" '{print $1,$2}' /etc/hosts ● cat /etc/hosts | awk -F "t" '{print $1,$2}'
  • 25. Basic Commands - sed ● sed 's/old_text/new_text/g' [file] ● sed -i 's/old_text/new_text/g' [file]
  • 26. Basic Commands - xargs ● ps -ef | grep node | awk '{print $2}' | xargs kill -9
  • 27. Nice tool - bash_it ● https://github.com/revans/bash-it ● Install: ○ Check a clone of this repo: git clone http://github.com/revans/bash-it.git ~/.bash_it ○ Run ~/.bash_it/install.sh ○ Edit your ~/.bash_profile file in order to customize bash-it.
  • 28. Vi
  • 29. Vi - View Mode
  • 30. Vi - Edit Mode
  • 31. Vi - Goto line & Search & Replace ● Goto line: :[line number] ● Search: /[key] ● Replace first: %s/[old]/[new] ● Replace all: %s/[old]/[new]/g
  • 32. Vi - split, vsplit ● :vsp ● :vsp [file] ● :sp ● :s[ [file] ● ctrl+w
  • 33. Vi - tabedit ● :tabe [file] ● gt ● n gt
  • 34. Vi - set ● :set nu / :set nonu ● :set paste
  • 35. Vi - execute command ● :![command]