dynamic variables

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Top Forums Shell Programming and Scripting dynamic variables - eval - expand etc. Post 302508071 by Chubler_XL on Friday 25th of March 2011 03:11:57 PM

03-25-2011

Moderator

Just a logic problem - you were assigning VAR2 on 3rd loop:

Code:

example=1
for counter in 0 1 2; do
      if [ ! "$(eval echo "\$testing$example")" ]; then
            echo "FIRST LOOP, CREATING DYN VAR1"
            eval testing$example="test"
      else
         if [ ! "$(eval echo "\$testing2$example")" ]; then
              echo "SECOND LOOP, CREATING DYN VAR2"
              eval testing2$example="test"
         fi
            echo "COMPARING DYN VAR1 to DYN VAR2"
            if [ "$(eval echo \$testing$example)" == "$(eval echo \$testing2$example)" ]; then
                echo "MATCH"
                echo "CHANGING SECOND DYN VAR TO GET NO MATCH NEXT LOOP"
                eval testing2$example="test2"
            else
                echo "NO MATCH"
            fi
      fi
done

If your doing a lot of this sort of stuff why not write notdefined and dynval functions:

Code:

notdefined() {
[ ${!1-X} != ${!1-Y} ]
}
dynval() {
  printf ${!1}
}
example=1
for counter in 0 1 2; do
      if notdefined testing$example ; then
            echo "FIRST LOOP, CREATING DYN VAR1"
            eval testing$example="test"
      else
            if notdefined testing2$example ; then
              echo "SECOND LOOP, CREATING DYN VAR2"
              eval testing2$example="test"
            fi
            echo "COMPARING DYN VAR1 to DYN VAR2"
            if [ "$(dynval testing$example)" == "$(dynval testing2$example)" ]; then
                echo "MATCH"
                echo "CHANGING SECOND DYN VAR TO GET NO MATCH NEXT LOOP"
                eval testing2$example="test2"
            else
                echo "NO MATCH"
            fi
      fi
done

Last edited by Chubler_XL; 03-25-2011 at 04:28 PM..

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dh-exec-subst

DH-EXEC-SUBST(1)						      dh-exec							  DH-EXEC-SUBST(1)

NAME

       dh-exec-subst - Debhelper executable file substition scripts

SYNOPSIS

       #! /usr/bin/dh-exec
       src/libfoo-*.so.* debian/foo-plugins/usr/lib/foo/${DEB_HOST_MULTIARCH}/

DESCRIPTION

       Being a sub-command of dh-exec(1), this program must not be ran directly, but through dh-exec, which automatically runs all available
       sub-commands if run bare; or explicitly with dh-exec --with=subst.

       It is a wrapper around the various other substitution helpers, and will pipe the input file through all the available substitution helpers.
       It is up to these scripts to do the actual work.

       When a helper fails to expand a variable within its input, it will leave it as-is, so that later in the pipeline it can perhaps be expanded
       by another program.

SCRIPTS

       dh-exec-subst-env
	      Substitutes any of the available, exported environment variables into its input. It does not do any kind of filtering: whatever is
	      available in the environment, will be available for substitution, however unsafe that may be.

       dh-exec-subst-multiarch
	      Attempts to expand any of the variables known to dpkg-architecture(1), mostly useful for multi-arch support.

	      The command will query dpkg-architecture(1) directly, and does not rely on environment variables set (as the called program will
	      prefer already set environment variables anyway).

ENVIRONMENT

       DH_EXEC_SCRIPTDIR
	   Indicates which directory the command-specific scripts should be sought for. If not specified, scripts will be searched for in
	   /usr/share/dh-exec/.

FILES

       $DH_EXEC_SCRIPTDIR/dh-exec-subst-*
	   The various scripts for the higher-level program.

SEE ALSO

       debhelper(1), dh-exec(1)

AUTHOR

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								    2012-05-03							  DH-EXEC-SUBST(1)

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