debugging preinst

root@localhost:/deb/extract/fontconfig-config# export DPKG_MAINTSCRIPT_NAME=preinst
root@localhost:/deb/extract/fontconfig-config# export_MAINTSCRIPT_ARCH=ALLn
root@localhost:/deb/extract/fontconfig-config# export DPKG_MAINTSCRIPT_PACKAGE=fontconfig-config_2.11.0-6.7
root@localhost:/deb/extract/fontconfig-config# bash -x  dpkg-maintscript-helper rm_conffile /etc/fonts/fonts.dtd 2.10 -- -i
Display all 261 possibilities? (y or n)
root@localhost:/deb/extract/fontconfig-config# bash -x  dpkg-maintscript-helper rm_conffile /etc/fonts/fonts.dtd 2.10 -- -i
+ set -e
++ basename dpkg-maintscript-helper
+ PROGNAME=dpkg-maintscript-helper
+ version=1.18.25
+ command=rm_conffile
+ '[' 5 -gt 0 ']'
+ shift
+ case "$command" in
+ rm_conffile /etc/fonts/fonts.dtd 2.10 -- -i
+ local CONFFILE=/etc/fonts/fonts.dtd
+ local LASTVERSION=2.10
+ local PACKAGE=--
+ '[' 2.10 = -- ']'
+ '[' -- = -- -o -z -- ']'
+ PACKAGE=fontconfig-config_2.11.0-6.7
+ '[' /etc/fonts/fonts.dtd '!=' -- -a 4 -gt 0 ']'
+ shift
+ '[' 2.10 '!=' -- -a 3 -gt 0 ']'
+ shift
+ '[' -- '!=' -- -a 2 -gt 0 ']'
+ '[' 2 -gt 0 ']'
+ shift
+ '[' -n fontconfig-config_2.11.0-6.7 ']'
+ '[' -n -i ']'
+ '[' -n preinst ']'
+ '[' /etc/fonts/fonts.dtd '!=' etc/fonts/fonts.dtd ']'
+ validate_optional_version 2.10
+ local VERSION=2.10
+ '[' -z 2.10 ']'
++ dpkg --validate-version -- 2.10
+ VERSIONCHECK='dpkg: unrecognized option '\''--validate-version'\''
BusyBox v1.27.2 (Debian 1:1.27.2-2) multi-call binary.

Usage: dpkg [-ilCPru] [-F OPT] PACKAGE

Install, remove and manage Debian packages

    -i,--install    Install the package
    -l,--list   List of installed packages
    --configure Configure an unpackaged package
    -P,--purge  Purge all files of a package
    -r,--remove Remove all but the configuration files for a package
    --unpack    Unpack a package, but don'\''t configure it
    --force-depends Ignore dependency problems
    --force-confnew Overwrite existing config files when installing
    --force-confold Keep old config files when installing'
+ error 'dpkg: unrecognized option '\''--validate-version'\''
BusyBox v1.27.2 (Debian 1:1.27.2-2) multi-call binary.

Usage: dpkg [-ilCPru] [-F OPT] PACKAGE

Install, remove and manage Debian packages

    -i,--install    Install the package
    -l,--list   List of installed packages
    --configure Configure an unpackaged package
    -P,--purge  Purge all files of a package
    -r,--remove Remove all but the configuration files for a package
    --unpack    Unpack a package, but don'\''t configure it
    --force-depends Ignore dependency problems
    --force-confnew Overwrite existing config files when installing
    --force-confold Keep old config files when installing'
+ echo 'dpkg-maintscript-helper: error: dpkg: unrecognized option '\''--validate-version'\''