CSH syntax example reference

 

CSH instance reference:

 

# ! /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 'whoam '. 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 = 'whoam'

# 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 less than or equal to
= numerical greater than or equal to
numerical greater than

-E file merely exists (may be protected from user)
-R file exists and is readable by user
-W file is writable by user
-X file is executable by user
-O file is owned by user
-Z file has size 0
-F file is an ordinary file
-D 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
@ N --
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 John Doe 101 Surrey Lane London, UK 5e7 j2k
Angela langsbury 99 Knightsbridge, Apt. K4 Liverpool
John Major 10 Downing Street London
Here

Cat> tempdata <endofdata
53.3 94.3 67.1
48.3 01.3 99.9
42.1 48.6 92.8
Endofdata

Exit 0

 

From:Http://www-cs.canisius.edu/ONLINESTUFF/UNIX/shellprogramming.html

 

Complete!