[ILUG] Shell quoting mystery

[Andrew]

On Friday 23 May 2008 15:40:32 Lars Hecking wrote:
>  bash 2.05b.1(1) on RHEL3.
>
>  I have a script that builds a search expression for find and then runs
>  find. For some reason, an expression which includes "*" gets quoted
>  with single quotes and therefore literally looks for 'foo.*' instead
>  of all foo.*.
If it does not get quoted, then it will get expanded to a list of files, which 
is not what find requires.
>
> FINDRX_C="-name core.\* -o -name core"
> FINDRX="${FINDRX_C}${FINDRX_N}${FINDRX_X}"
> ...
> find ${d} -type d -name .snapshot -prune -o -type f \( $FINDRX \)`
> ...
>
>  becomes
> sh -x ...
> ...
> + FINDRX=-name core.\* -o -name core
> ++ find /home -type d -name .snapshot -prune -o -type f '(' -name 'core.\*'
> -o -name core ')'
>
>  I tried all sorts of quoting tricks, but can't get rid of the single
> quotes surrounding core.\*. Any ideas?
For the find command, you need to run the command (in part):
	find '-name' 'core.*'
without the backslash.  find will check whether each filename under 
consideration matches the wildcard supplied, and the problem you have is 
preventing the shell from expanding the wildcard while simultaneously wanting 
it to separate words.

If you want to set up the command in variables beforehand, you could do it 
like this:
  FINDRX_C[0]="-name"
  FINDRX_C[1]="core.*"
  FINDRX_C[2]="-o"
  FINDRX_C[3]="-name"
  FINDRX_C[4]="core"
# then you see your required result with:
  find "${FINDRX_C[@]}"
which with set -x says:
+ find -name 'core.*' -o -name core

At this point, you would be justified in thinking there's a better way.  I 
can't think of one, but if you are into spectacularly ugly hacks ...
	FINDRX_C="-iname corE.* -o -name core".

&:-)