How do I assign alias(es) to my C Shell (csh)? 




  





    
	
  1. 
		Syntax for Defining Alias
	
  2. 
		C shell alias examples
	
  3. 
		Managing Alias(es)
	












        Syntax for Defining Alias





  




Alias is a pseudonym  or shorthand for a command or series of commands, i.e., 
a convenient macro for frequently used command or a series of commands.
An alias definition affects the current shell execution
environment  and the execution environments of the subshells
of the current shell. The alias definition will 
not affect the parent process of the current shell  
nor any utility environment invoked by the shell.



For C shell, you can define alias(es) using





alias  alias_name  'command'





syntax in .cshrc file in your root
directory. You can define as many aliases as you want (as long as you
can remember alias names) in .cshrc.







	







        C shell alias examples





  










        
	
                
        
        
	
	Collection of useful aliases







For example, to create a simple command alias, first open your .cshrc file in your home directory using any text
editor of your choice.





alias del 'rm -i'





This creates an alias del for the command 
"rm -i" which prompts you for confirmation that you want to remove a
file before it does so.



To create a command alias that consists of a series of commands,





alias ll '/usr/bin/ls -Flsa |more'





This creates an alias ll for the command
"ls" with "Flsa" flags and pipe the result to "more" command to display
the result one screenful at a time.



Of course, you can refer to another command alias within an alias,





alias h history

alias rev  'h | tail -10'





The first command assigns an alias h to the
"history" command. The next
command assigns another alias rev to the
command "h | tail -10". This takes the output from the alias h (= the "history" command) and pipes it through
the "tail" command to list the
ten most recent commands in the command history.



Here an example to pass command arguments to the alias,





alias print 'lpr \\!^ -Php4'





Now, to print a file to the CEE UCL default printer "hp4," 
you can enters a command such as:





$ print ohboy.f





The notation "!^" causes the first argument to the command
alias print to be inserted in 
the command at this point. The command that is carried out is:





lpr ohboy.f -Php4





Of course, you can also pass multiple arguments to a command alias.





alias mprint 'lpr \\!* -Php4'





The notation "!*" causes multiple arguments given to the alias
mprint to be inserted in 
the command.  If you enters following command





$ mprint ohboy.f headache.txt huge_bug_list.ps





the actual command would look like





lpr ohboy.f headache.txt huge_bug_list.ps -Php4





Notice that the "!" character is preceeded by a 
"\\" to prevent it being interpreted by C shell as a metacharacter.  
The reason is that "!" is one of shell metacharacters
that are inetrpreted as something other than the character or symbol
by the shell. FYI, here's a list of all metacharacters for C shell.




    

  •    ;  &  ( )  |  ^  <  >  ~  %  { }

  •    $  #   '  "  \  @@  *  ?  [ ]  -  !

  •    Newline	(a <Return>)

  •    Space	(a <Space>)

  •    Tab	(a <Tab>)








        








        Managing Alias(es)





  







    

  1. To display the value of an alias known to the shell,
type; 

    


    
$ alias

    

    

To display the current value for a particular alias, use
the command;

    


    
$ alias  name_of_alias

    

    

For example, to display the current value of the alias
named print;

    


    
$ alias  print
    
lpr \\!^ -Php4

    

    

    


  2. Once alias definition is save in .cshrc,
the alias will be in effect next time you login. If you wish to make the
alias in effect immediately, update your alias definition by sourcing
out .cshrc

    


    
$ source .cshrc

    

    

    


  3. To cancel a command alias during your current login
session use the command;

    


    
$ unalias  name_of_alias

    

    

For example,

    


    
$ unalias  print

    

    

will cancel the command alias print 
for your current login session.
You will have to remove the alias definition from your
.cshrc file if you want to cancel the alias permanently.

    








For further details, RTFM on "alias."