#!/bin/csh -vx#csh -vx show the command before running to help debug#just to check syntax#csh -n $0#argvif ($#argv < 2) then    echo "Sorry, but you entered too few parameters"    echo "usage:  $0 arg1 arg2    exitendifset arg1 = $1set arg2 = #2foreach i ($*)   echo $iend   #execute commandsecho "Hello there `whoami`.  How are you today?"echo "You are currently using `hostname` and the time is `date`"echo "Your directory is `pwd`"whoamihostnamedatepwd#varset name = Markecho $nameset name = "Mark Meyer" # if the string has space, must use ""echo $name# it means set to NULLset name = unset name# get user inputset x = $<  set current_user = `whoami`#buildin varsecho $user      # who am I?echo $status    # a numeric variable, usually used to retun error codes#Arithmetic variables@ i = 2@ k = ($x - 2) * 4@ k = $k + 1@ i--@ i++#arrayset name = (mark sally kathy tony)echo $#name    # num of the arrayecho $name[1]echo $name[4]echo $name[2-3]echo $name[2-]        # all elements from 2 to the endecho $name[1-3]echo $name[$i]set name = ($name doran)set name = (doran $name)set name = ($name[1-2] alfie $name[3-])shift name  # get rid of the frist element of the arrayshift #if no argument is given, it will get rid of argv#Expressions and operators==        equal     (either strings or numbers)!=        not equal     (either strings or numbers)=~        string match!~        string mismatch<=        numerical less than or equal to>=        numerical greater than or equal to>         numerical greater than<         numerical less than-e file           file merely exists (may be protected from user)-r file           file exists and is readable by user-w file           file is writable by user-x file           file is executable by user-o file           file is owned by user-z file           file has size 0-f file           file is an ordinary file-d file           file is a directory!   -- negate                 &&  -- logical and||  -- logical or#if-else# run cmd as if expressionif ({grep -s junk $1}) then     echo "We found junk in file $1"endif# check if the var is definedif ($?dirname) then     ls $dirnameendifif (-e somefile) then grep $1 somefileelse echo "Grievous error!  Database file does not exist".endif#foreachforeach i (*)    if (-f $i) then        echo "============= $i ==================="        head $i    endif    if (-d $i) then        (cd $i; headers)    endifend#whilewhile ($#argv > 0)    grep $something $argv[1]end@ n = 5while ($n)      # do something     @ n--end#switch-caseswitch ($argv[$i]) case quit:        break        # leave the switch statement case list:        ls        breaksw case delete: case erase:        @ k = $i + 1        rm $argv[$k]        breakswendsw    #here documentgrep $i <
    
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