set
set name
set name=word
set name[index]=word
set name=(wordlist)
The first form of the command shows the value of all shell variables. Variables that have other than a single word as their value print as a parenthesized word list. The second form sets name to the null string. The third form sets name to the single word. The fourth form sets the indexth component of name to word; this component must already exist. The final form sets name to the list of words in wordlist. The value is always command and file name expanded.
@
@ name=expr
@ name[index]=expr
The first form prints the values of all the shell variables. The second form sets the specified name to the value of expr. If the expression contains <, >, &, or |, then at least this part of the expression must be placed within ( ). The third form assigns the value of expr to the indexth argument of name. Both name and its indexth component must already exist.
The operators *=, +=, and so forth are available as in C. The space separating the name from the assignment operator is optional. Spaces are, however, mandatory in separating components of expr that would otherwise be single words.
Special postfix ++ and -- operators increment and decrement name respectively. For example "@ i++" increments the variable i.
Look at the following URL for more definitions:
https://www.mkssoftware.com/docs/man1/csh.1.asp