Help! Csh is eating my brain....

[Frederick M. Avolio]

In article <366 at zaphod.UUCP>, flory at zaphod.UUCP (Trevor Flory) writes:
> Hello All;
> 	I'm trying to debug a csh script written by someone who
> 	knew what he was doing I'm sure.  Below is a fragment of
> 	the script which I find rather difficult to understand:
> 		...
> 		alias readandset 'echo -n \!:1 ; set \!:2 = $< ' 
> 		...
> 		readandset "Choice? " chvar
> 		...
> 		if("$chvar" == "quit") ....
> 
> 	In particular I'd like to know what \!:1 or \!:2 means/does.

If you look at a command line, the first word is in position 0, the
next in position 1, and so on.  !:n (where n is a non-negative number)
the csh replaces the string with the word in the nth position from the
previous command.  (!:1 is the first word.  !22:3 is the 3rd word from
command #22 in the history and so on....)

Example --

% ls -ld t*
drwx--x--x 16 avolio       1024 Oct 17 15:23 text
-rw-r--r--  1 avolio          0 Oct 19 10:10 todo

% ls !:2
ls t*
todo

text:

cust.support	  decnet.info	    decuac	      kermit
mail		  paths		    products	      qpr
training	  uac		    uig		      ultrix11
ultrix32	  venix

-----

% echo a b c
a b c

% echo !:3
echo c
c

%


And so on.....

Fred.