Shell and perl scripting classes in mumbai

Shell and perl scripting classes in mumbai

• 1.
  Computer Science Lab1
• 2.
  2 SShheellll SSccrriippttiinngg((CC sshheellll)) by
• 3.
  3 CCoonntteennttss Cshell – First Script – Getting User Input – Command Line Arguments – Conditionals and File Testing – Switch & Loops Programming with C Shell – mailingList Summary & Resources
• 4.
  4 CC SShheellll #! /bin/csh  set name = hello -> echo $name $array = ( element1 elemsnt2 ) $array[1] , $array[2]
• 5.
  5 CC SShheellll–– FFiirrsstt SSccrriipptt  ${LOGNAME} – Print user’s name  `unix command` – Enclosed in back quotes – Performed command substitution – Ex) `date`  uname –n – Display the machine name  ps –ef | grep “^ *$LOGNAME” – User’s processes are printed  chmond –u+x greetme
• 6.
  6 CC sshheellllGGeettttiinngg UUsseerr IInnppuutt $< – user input (std) without newline $array = ($name) – An array is created Arithmetic ( operators ): @ integer + , - , / , * , % , << , >> += , -=, *=, /=, ++, -- • Ex) @ sum = 4+6 – Space is required after @
• 7.
  7 CCsshheellll DDeebbuuggggiinnggssccrriippttss Echo (-x) and Verbose (-v) – csh –x scriptname (command ) • Display each line after variable substitution and before execution – set echo , unset ( in the file )
• 8.
  8 c Cshellcoommmmaanndd lliinnee aarrgguummeenntt $0 - The name of the script $1, $2, $3,..${10} – Parameters are referenced by number $* - All positional parameters $argv[1], $argv[2] – The first argument , second … $argv[*] or $argv – all arguments $#argv – The number of arguments (size) $argv[$#argv] – The last argument
• 9.
  9 Cshell Conditionalccoonnssttrruuccttss  == , != , <, > , >= , <= , !  =~ , !~ – String matches ex) $ans =~ [Yy]* || , && – Logical operator
• 10.
  10 CCsshheellll iiffeexxaammpplleess IIff(( eexxpprreessssiioonn )) tthheenn CCoommmmaanndd eellssee CCoommmmaanndd eennddiiff Ex) if ( $#argv != 1) then echo “$0 requires an argument” exit 1 endif
• 11.
  11 CCsshheellll iiffeexxpprreessssiioonn  set name = $< If( “$name” != “” ) then grep “$name” data file endif  If( $answer =~ [Yy]* ) then mail bob < message else mail jon < datafile endif  set x = 1 , y = 2, z = 3 If( (“$x” && “$y”) || ! “$z”) then echo TRUE  If( $#argv == 0 ) exit 1
• 12.
  12 CCsshheellll iiffccoommmmaanndd  If { (command) } then command endif  If { ( who | grep $1 >& /dev/null ) } then echo $1 is logged on endif  startover: set grade = $< if( “$grade” < 0 || “$grade” > 100 ) then echo “Illegal grade” goto startover endif
• 13.
  13 CCsshheellll iiffffiillee tteessttiinngg  if( ! –e $file ) : file exists  if( -d $file ) : a direcotry file  if( -f $file ) : a plain file  if( ! –z $file ) : zero length  if( -r $file && -w $file): readable and writable  if( -x $file ): executable
• 14.
  14 CCsshheellll SSwwiittcchh set color = $< sswwiittcchh ((“$color”)) ccaassee bl*:: echo I feel $color bbrreeaakkssww ddeeffaauulltt:: echo $color not one of them bbrreeaakkssww eennddssww
• 15.
  15 CCsshheellll ffoorr ffoorreeaacchh vvaarriiaabbllee ((wwoorrddlliisstt)) ccoommmmaannddss eenndd – foreach person ( bob sam sue fred) mail $person < letter end – foreach person (`cat maillist`) mail $person <<EOF Hi $person EOF end
• 16.
  16 CCsshheellll wwhhiillee  set num = 0 wwhhiillee ($num < 10 ) echo $num @ num++ eenndd  rreeppeeaattee takes two argument( number, command) – Ex) %repeate 3 echo hello hello hello hello
• 17.
  17 CCsshheellll WWhhiillee sshhiifftt command – Shifts the argv array by one word • Ex) While( $#argv) echo $argv shift end %loop a b c a b c b c c
• 18.
  18 CCsshheellll WWhhiillee break && continue command set answer = $< while( “$answer” !~ [Mm]* ) echo “Wrong! Try again.” set answer = $< if( “$answer” =~ [Mm]*) break; end
• 19.
  19 PPrrooggrraammmmiinngg wwiitthhCC sshheellll mailingList – data • Hello XXX, – friends ( emails )
• 20.
  20 RReessoouurrcceess Oursites  http://vibranttechnologies.co.in/  http://vibrantgroupmumbai.blogspot.in/
• 21.
  Computer Science Lab21