Path: utzoo!attcan!uunet!husc6!bbn!mit-eddie!uw-beaver!teknowledge-vaxc!mkhaw
From: mkhaw@teknowledge-vaxc.ARPA (Mike Khaw)
Newsgroups: comp.sources.d
Subject: Re: v03i020: "redo"
Keywords: csh history editing
Message-ID: <22746@teknowledge-vaxc.ARPA>
Date: 25 May 88 23:16:05 GMT
References: <8805171730.AA22099@cope> <853@uvm-gen.UUCP>
Reply-To: mkhaw@teknowledge-vaxc.UUCP (Mike Khaw)
Organization: Teknowledge, Inc., Palo Alto CA
Lines: 43
Posted: Wed May 25 16:16:05 1988

In article <853@uvm-gen.UUCP> hartley@uvm-gen.UUCP (Stephen J. Hartley) writes:
...
+< -----------------CLEAR-TEXT VERSION----DO *NOT* CUT AND USE--------------------
+< # Edit history list at line containing last command (open mode).
+< # Get up to 22 most recent commands.
+< # To work properly, put in .login:  alias r source /usr/local/bin/redo
+< # Author unknown.
+< history -h 22 >! /tmp/redo.$$
+< 
+< # Make CR map to :wq! and start ex quietly at 2nd to last line in open mode.
+< ex - '+map ^M :.wq\!^[|$-1 open' /tmp/redo.$$
+< tail -1 /tmp/redo.$$ >! /tmp/cmd.$$
+< 
+< # Insert into history without executing.
+< source -h /tmp/cmd.$$
+< 
+< # Clear out temporaries.
+< /bin/rm -f /tmp/{cmd,redo}.$$
+< 
+< # If thing chosen to redo is the redo alias itself then DON'T redo it.
+< if (!-2:0 != !!:0) !!
+< 
+
+I tried this and noticed that commands "redone" this way do not go
+through csh aliasing, i.e. if you have "mv" aliased to "mv -i" and
+then "redo" some previous command that had a "mv" in it, then you will
+have a plain "mv" redone and run the risk of clobbering a file.
+Does anybody know why the aliasing check is bypassed?

I don't know "why", but it has something to do with the way csh handles the
"if" expression at the end.  Changing it to:

	if (!-2:0 != !!:0) then
		!!
	endif

makes it work correctly (in "tcsh" and the csh that comes with ultrix 2.2)

Mike Khaw
-- 
internet: mkhaw@teknowledge.arpa
uucp:	  {uunet|sun|ucbvax|decwrl|uw-beaver}!mkhaw%teknowledge-vaxc.arpa
hardcopy: Teknowledge Inc, 1850 Embarcadero Rd, POB 10119, Palo Alto, CA 94303