11.15 Changing C Shell History Characters with histchars

The existence of special characters (particularly ! ) can be a pain; you may often need to type commands that have exclamation points in them, and occasionally need commands with carets ( ^ ). These get the C shell confused unless you "quote" them properly. If you use these special characters often, you can choose different ones by setting the histchars variable. histchars is a two-character string; the first character replaces the exclamation point (the "history" character), and the second character replaces the caret (the "modification" character ( 11.5 ) ). For example:

% 

set histchars='@#'


% 

ls file*


file1   file2   file3
% 

@@

   
Repeat previous command (was 


!!


)

ls file*
file1   file2   file3
% 

#file#data#

   
Edit previous command (was 


^file^data^


)

ls data*
data4   data5

An obvious point: you can set histchars to any characters you like, but it's a good idea to choose characters that you aren't likely to use often on command lines. Two good choices might be # (hash mark) and , (comma). [2]

[2] In the C shell, # is a comment character ( 44.2 ) only in non-interactive shells. Using it as a history character doesn't conflict because history isn't enabled in non-interactive shells.