Intel XENIX 286 Programmers Guide (86) - Tenox.tc

csh: C Shell XENIX Programming
in your .login file. After setting noclobber, typing
date > now
causes an error message if the file now already exists. You can type
date >! now
if you really want to overwrite the contents of now. The " > !" is a special syntax
indicating that overwriting or "clobbering" the file is permitted. (The space between
the exclamation point (!) and the word "now" is critical here, as "!now" would be an
invocation of the history mechanism (described below) and would have a very different
effect.)
Using the C Shell History List
The C shell can maintain a history list containing the text of previous commands. You
can use a notation that reuses commands, or words from commands, in forming new
commands. This notation can be used to repeat previous commands or to correct minor
typing mistakes in commands.
The following example gives a sample session using the history mechanism of the C
shell. The example assumes that the bug.c file exists and that its contents are exactly
as shown below. Boldface indicates user input.
8-4
% cat bug.c
main( )
{
printf("hello);
}
% cc !$
cc bug.c
bug.c (5) : warning 8: newline in string constant
bug.c (5): error 59 : syntax error: ' } '
% ed !$
ed bug.c
29
* 4s/);/");/p
printf(" hello");
*w
30
* q
% !c
cc bug.c
% a.out
hello% !e
ed bug.c
30
* 4s/lo/lo\\n/p
pri ntf(" hello\n ");