Re: Zsh Guide chapter 5 (substitutions)

Re: Zsh Guide chapter 5 (substitutions)

[Peter Stephenson]

Bart Schaefer wrote:
> On Aug 16, 12:00am, Peter Stephenson wrote:
>   ./myscript 2> >(grep -v idiot >error.log) |
>        process-output >output.log
> 
> Don't remove the space between them, either: for what
>                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> that will do, and for more on the meaning of `2>', see the section on
> redirections, below.
> ---------------
> 
> I don't know what you're driving at, there.

I think the answer is something on the lines of `I don't know what the hell
I'm talking about'.

-- 
Peter Stephenson <pws@csr.com>                  Software Engineer
CSR Ltd., Unit 300, Science Park, Milton Road,
Cambridge, CB4 0XL, UK                          Tel: +44 (0)1223 392070


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Re: Zsh Guide chapter 5 (substitutions)

[Peter Stephenson]

Bart Schaefer wrote:
> And that's all, except that I'm left puzzling over this:
> 
>  The other tricky point is the use of double quotes in the eval. That
>  means that if the second argument has a double quote in it, the shell
>  will get very confused.
> 
> This refers to:
> 
>      eval "f2=\"$result\""
> 
> I'm left wondering whether
> 
>      f2=${(e)result}
> 
> wouldn't be equivalent and avoid the need for the double quotes?

Well, hmm.  Yeah.

Fixed some other things, too.

Index: Functions/Misc/zmv
===================================================================
RCS file: /cvsroot/zsh/zsh/Functions/Misc/zmv,v
retrieving revision 1.8
diff -u -r1.8 zmv
--- Functions/Misc/zmv	2001/04/02 13:04:05	1.8
+++ Functions/Misc/zmv	2001/08/28 20:19:20
@@ -103,10 +103,6 @@
 #   are now turned off by default.  To force the use of glob qualifiers,
 #   give the flag -Q.
 #
-#   The second argument is re-evaluated in order to expand the parameters,
-#   so quoting may be a bit haphazard.  In particular, a double quote
-#   will need an extra level of quoting.
-#
 #   The pattern is always treated as an extendedglob pattern.  This
 #   can also be interpreted as a feature.
 #
@@ -130,7 +126,7 @@
     print -P "%N: unrecognized option: -$OPTARG" >&2
     return 1
   fi
-  eval "opt_$opt=${OPTARG:--$opt}"
+  eval "opt_$opt=${(q)OPTARG:--$opt}"
 done
 (( OPTIND > 1 )) && shift $(( OPTIND - 1 ))
 
@@ -153,6 +149,7 @@
 
 pat=$1
 repl=$2
+shift 2
 
 if [[ -z $action ]]; then
   # We can't necessarily get the name of the function directly, because
@@ -229,9 +226,9 @@
   fi
   [[ -e $f && $f = (#b)${~pat} ]] || continue
   set -- "$match[@]"
-  eval g=\"$repl\"
+  g=${(e)repl}
   if [[ -z $g ]]; then
-    errs=($errs "$f expanded to empty string")
+    errs=($errs "\`$f' expanded to an empty string")
   elif [[ $f = $g ]]; then
     # don't cause error: more useful just to skip
     #   errs=($errs "$f not altered by substitution")
@@ -255,7 +252,7 @@
 for f in $files; do
   [[ -z $to[$f] ]] && continue
   exec=($action ${=opt_o} $opt_s -- $f $to[$f])
-  [[ -n $opt_i$opt_n$opt_v ]] && print -- $exec
+  [[ -n $opt_i$opt_n$opt_v ]] && print -r -- ${(q)exec}
   if [[ -n $opt_i ]]; then
     read -q 'opt?Execute? ' || continue
   fi

-- 
Peter Stephenson <pws@pwstephenson.fsnet.co.uk>
Work: pws@csr.com
Web: http://www.pwstephenson.fsnet.co.uk