shells (was Re: IP-aliasing)

[Craig Sanders <cas@taz.net.au>]

On Tue, 6 Aug 1996, Emilio Lopes wrote:

> >>>>> "CS" == Craig Sanders <cas@taz.net.au> wrote:
> 
> CS> I'd like to see a bourne-like shell with perl-like regexp stuff
> CS> (mainly sed & grep) built in - i'd switch to that in a flash.
> 
> People may say it's called ksh93. IMHO, it may seem somewhat
> interesting, but I really don't like it. Look likes tcl... :-)

zsh seems to have some of these features.

see http://www.mal.com/zsh/ for full details, but this looks useful:

        and a substitution modifier: 

        % echo $name:s/foo/bar/
        bar.c
        % ls
        foo.c    foo.h    foo.o    foo.pro
        % for i in foo.*; mv $i $i:s/foo/bar/
        % ls
        bar.c    bar.h    bar.o    bar.pro


it's only simple substitution, though.  no regexp.

        (siva-cas) ~$ zsh
        % fred=xyz.abc.zzz
        % echo $fred
        xyz.abc.zzz

lets try a regexp subsitution ala sed:
        % echo $fred:s/\(...\).\(...\).\(...\)/\3\2\1/
        xyz.abc.zzz
ok.  that obviously doesn't work.  lets try a different format:
        % echo $fred:s/(...).(...).(...)/\3\2\1/
        xyz.abc.zzz
nope. 


you can string together multiple substitions, though:
        % echo $fred:s/abc/111/                       
        xyz.111.zzz
        % echo $fred:s/abc/111/:s/xyz/222/
        222.111.zzz
        % echo $fred:s/abc/111/:s/xyz/222/:s/zzz/333/
        222.111.333


zsh looks like it's got nice stuff out of sh/bash, ksh, and csh.

looks useful, but it doesn't get eliminate the need to fork sed and
grep.

hmmm...the substitution facility could be useful for standardising
responses in a case statement:

read yesno
case $yesno:l:s/yes/y/:s/no/n/ in
  y) do_yes ;; 
  n) do_no ;;
  *) do_error ;;
esac




it's probably too non-standard to use for debian.{pre,post}{rm,inst} scripts
but i might switch to it for my personal use.