What are the csh script syntax

This article mainly introduces "what are the csh script grammars". In daily operation, I believe many people have doubts about what csh script syntax problems there are. The editor consulted all kinds of materials and sorted out simple and easy-to-use operation methods. I hope it will be helpful for you to answer the doubts about "what csh script syntax there are"! Next, please follow the editor to study!

Csh instance reference:

The code is as follows:

#! / bin/csh-vx

# csh-vx show the command before running to help debug

# just to check syntax

# csh-n $0

# argv

If ($# argv

< 2) then echo "Sorry, but you entered too few parameters" echo "usage: $0 arg1 arg2 exit endif set arg1 = $1 set arg2 = #2 foreach i ($*) echo $i end #execute commands echo "Hello there `whoami`. How are you today?" echo "You are currently using `hostname` and the time is `date`" echo "Your directory is `pwd`" whoami hostname date pwd #var set name = Mark echo $name set name = "Mark Meyer" # if the string has space, must use "" echo $name # it means set to NULL set name = unset name # get user input set x = $< set current_user = `whoami` #buildin vars echo $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++ #array set name = (mark sally kathy tony) echo $#name # num of the array echo $name[1] echo $name[4] echo $name[2-3] echo $name[2-] # all elements from 2 to the end echo $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 array shift #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 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 expression if ({grep -s junk $1}) then echo "We found junk in file $1" endif # check if the var is defined if ($?dirname) then ls $dirname endif if (-e somefile) then grep $1 somefile else echo "Grievous error! Database file does not exist". endif #foreach foreach i (*) if (-f $i) then echo "============= $i ===================" head $i endif if (-d $i) then (cd $i; headers) endif end #while while ($#argv >

0)

Grep $something $argv [1]

End

@ n = 5

While ($n)

# do something

@ nmuri-

End

# switch-case

Switch ($argv [$I])

Case quit:

Break # leave the switch statement

Case list:

Ls

Breaksw

Case delete:

Case erase:

@ k = $I + 1

Rm $argv [$k]

Breaksw

Endsw

# here document

Grep $I