diff --git a/interface_information.sh b/interface_information.sh
new file mode 100755
index 0000000..afd97e6
--- /dev/null
+++ b/interface_information.sh
@@ -0,0 +1,130 @@
+#!/bin/dash
+
+##
+# This creates function that will gather some system informations
+# and propagate them as environment variables.
+#
+
+. ./utils.sh
+
+##
+# retrieve interfaces. I prefer using ip if it is
+# available, else I fallback to ifconfig... don't know
+# how to retrieve this information on other systems.
+# This also exports the environment variables.
+#
+get_interface_data() {
+	local NO=1
+
+	if [ ${IP} ]
+	then
+		get_interface_data_ip
+	else
+		if [ ${IFCONFIG} ]
+		then
+			get_interface_data_ifconfig
+		else
+			${LOGGER} -p local0.warn 'Found no way to retrieve interface information.'
+		fi
+	fi
+
+	export NINTERFACES
+	export CLASSES
+
+	while [ ${NO} -le ${NINTERFACES:=0} ]
+	do
+		export IF${NO}_NAME IF${NO}_MAC IF${NO}_STATE IF${NO}_IPV4 IF${NO}_IPV6
+		NO=$((NO+1))
+	done
+}
+
+##
+# get the interface information from the ip tool
+#
+get_interface_data_ip() {
+	eval $(${IP} -o link | ${AWK} '{
+		sub(/:/,"",$1);
+		no=$1;
+		sub(/:/,"",$2);
+		name=$2;
+		for (i=3; i<NF; i++) {
+			if ($i == "state") {
+				i++; state=$i
+			}
+			if ($i ~ /link/) {
+				i++; mac=$i;
+				classes=classes mac " "
+			}
+		}
+		print "IF" no "_NAME=" name ";IF" no "_STATE=" state ";IF" no "_MAC=" mac ";";
+		if ("UP" == state) classes=classes mac " "
+	}
+	BEGIN {
+		classes=""
+	}
+	END {
+		print "CLASSES=\"${CLASSES}" classes " \";";
+		print "NINTERFACES=" FNR ";"
+	}')
+
+	eval $(${IP} -o addr | ${AWK} '{
+		sub(/:/,"",$1);
+		no=$1;
+		if ($3 == "inet") {
+			sub(/[\/%].*/,"",$4);
+			print "IF" no "_IPV4=\"${IF" no "_IPV4}" $4 " \";";
+			classes=classes $4 " "
+		}
+		if ($3 == "inet6") {
+			sub(/[\/%].*/,"",$4);
+			print "IF" no "_IPV6=\"${IF" no "_IPV6}" $4 " \";";
+			classes=classes $4 " "
+		}
+	}
+	BEGIN {
+		classes=""
+	}
+	END {
+		print "CLASSES=\"${CLASSES}" classes " \";"
+	}')
+}
+
+##
+# get interface data via the ifconfig tool
+#
+get_interface_data_ifconfig() {
+	eval $(${IFCONFIG} -a | ${AWK} '
+	/ether/ { mac=$2 }
+	/inet / { ipv4=ipv4 $2 " " }
+	/inet6/ { ipv6=ipv6 $2 " " }
+	/^[^ \t]/ {
+		if ("" != ipv4 || "" != ipv6) state="UP"; else state="DOWN";
+		if ("" != name) {
+			print "IF" no "_NAME=" name ";IF" no "_STATE=" state ";IF" no "_MAC=" mac ";" \
+				"IF" no "_IPV4=\"${IF" no "_IPV4}" ipv4 " \";" \
+				"IF" no "_IPV6=\"${IF" no "_IPV6}" ipv6 " \";";
+			no++;
+		}
+		ipv4=ipv6="";
+		sub(/:/,"",$1);
+		name=$1
+	}
+	BEGIN {
+		no=1;
+	}
+	END {
+		if ("" != ipv4 || "" != ipv6) state="UP"; else state="DOWN";
+		print "IF" no "_NAME=" name ";IF" no "_STATE=" state ";IF" no "_MAC=" mac ";" \
+			"IF" no "_IPV4=\"${IF" no "_IPV4}" ipv4 " \";" \
+			"IF" no "_IPV6=\"${IF" no "_IPV6}" ipv6 " \";";
+		print "NINTERFACES=" no
+	}')
+}
+
+##
+# autorun this if sourced.
+#
+
+[ -z "${NINTERFACES}" ] && get_interface_data
+
+# vim: set ts=4 sw=4:
diff --git a/network_tools.sh b/network_tools.sh
new file mode 100755
index 0000000..0d71cab
--- /dev/null
+++ b/network_tools.sh
@@ -0,0 +1,57 @@
+#!/bin/dash
+
+. ./utils.sh
+
+##
+# Function calculates number of bit in a netmask
+#
+mask2cidr() {
+	local NBITS=0
+	local OLDIFS="${IFS}"
+	IFS=.
+
+	for DEC in $1
+	do
+		case ${DEC} in
+			255) NBITS=$((NBITS+8));;
+			254) NBITS=$((NBITS+7));;
+			252) NBITS=$((NBITS+6));;
+			248) NBITS=$((NBITS+5));;
+			240) NBITS=$((NBITS+4));;
+			224) NBITS=$((NBITS+3));;
+			192) NBITS=$((NBITS+2));;
+			128) NBITS=$((NBITS+1));;
+			0);;
+			*) NBITS=0; IFS="${OLDIFS}"; return 1
+		esac
+	done
+	IFS="${OLDIFS}"
+	${ECHO} "${NBITS}"
+}
+
+##
+# Function calculates a netmask from number of bits
+#
+cidr2mask() {
+	local I MASK=""
+	local FULL_OCTETS=$((${1}/8))
+	local PARTIAL_OCTET=$((${1}%8))
+
+	for I in 0 1 2 3
+	do
+		if [ ${I} -lt ${FULL_OCTETS} ]
+		then
+			MASK="${MASK}255"
+		elif [ ${I} -eq ${FULL_OCTETS} ]
+		then
+			MASK="${MASK}$((256-(1<<(8-${PARTIAL_OCTET}))))"
+		else
+			MASK="${MASK}0"
+		fi  
+		[ ${I} -lt 3 ] && MASK="${MASK}."
+	done
+
+	${ECHO} ${MASK}
+}
+
+# vim: set ts=4 sw=4:
diff --git a/run.sh b/run.sh
new file mode 100755
index 0000000..d27cb50
--- /dev/null
+++ b/run.sh
@@ -0,0 +1,46 @@
+#!/bin/dash
+
+##
+# This is a first test what static informations I can gather from a
+# system. The minimal requirement are the IP addresses because
+# on these I build up my classes.
+# The system type is also important...we might need to be running
+# on variuous UNIX flavours. (But for now we focus on various linux
+# flavours and maybe FreeBSD.
+#
+
+. ./utils.sh
+include_once ./system_information.sh
+include_once ../sysman/interface_information.sh
+include_once /home/ghopp/sysman/network_tools.sh
+
+##
+# report everysthing
+#
+
+${PRINTF} "%15s : %s\n" "OS" "${OS}"
+${PRINTF} "%15s : %s\n" "KERNEL" "${KERNEL}"
+${PRINTF} "%15s : %s\n" "VERSION" "${VERSION}"
+${PRINTF} "%15s : %s\n" "PLATFORM" "${PLATFORM}"
+${PRINTF} "%15s : %s\n" "DIST" "${DIST}"
+${PRINTF} "%15s : %s\n" "HOSTNAME" "${HOSTNAME}"
+${PRINTF} "%15s : %s\n" "# INTERFACES" "${NINTERFACES}"
+
+NO=1
+while [ ${NO} -le ${NINTERFACES:=0} ]
+do
+	eval printf \"%15s : %s\\\n\" \"IF${NO}_NAME\" \"\${IF${NO}_NAME}\"
+	eval printf \"%15s : %s\\\n\" \"IF${NO}_MAC\" \"\${IF${NO}_MAC}\"
+	eval printf \"%15s : %s\\\n\" \"IF${NO}_STATE\" \"\${IF${NO}_STATE}\"
+	eval printf \"%15s : %s\\\n\" \"IF${NO}_IPV4\" \"\${IF${NO}_IPV4}\"
+	eval printf \"%15s : %s\\\n\" \"IF${NO}_IPV6\" \"\${IF${NO}_IPV6}\"
+	NO=$((NO+1))
+done
+
+${PRINTF} "%15s : %s\n" "CLASSES" "${CLASSES}"
+
+echo
+echo $(mask2cidr 255.255.128.0)
+echo $(cidr2mask 17)
+eval echo \$\(cidr2mask $(mask2cidr 255.255.128.0)\)
+
diff --git a/system_information.sh b/system_information.sh
index 3d255d9..324bebc 100755
--- a/system_information.sh
+++ b/system_information.sh
@@ -1,155 +1,14 @@
 #!/bin/dash
 
 ##
-# This is a first test what static informations I can gather from a
-# system. The minimal requirement are the IP addresses because
-# on these I build up my classes.
-# The system type is also important...we might need to be running
-# on variuous UNIX flavours. (But for now we focus on various linux
-# flavours and maybe FreeBSD.
+# This creates function that will gather some system informations
+# and propagate them as environment variables.
 #
 
-
-# Function calculates number of bit in a netmask
-#
-mask2cidr() {
-	local NBITS=0
-	local OLDIFS="${IFS}"
-	IFS=.
-
-	for DEC in $1
-	do
-		case ${DEC} in
-			255) NBITS=$((NBITS+8));;
-			254) NBITS=$((NBITS+7));;
-			252) NBITS=$((NBITS+6));;
-			248) NBITS=$((NBITS+5));;
-			240) NBITS=$((NBITS+4));;
-			224) NBITS=$((NBITS+3));;
-			192) NBITS=$((NBITS+2));;
-			128) NBITS=$((NBITS+1));;
-			0);;
-			*) NBITS=0; IFS="${OLDIFS}"; return 1
-		esac
-	done
-	IFS="${OLDIFS}"
-	${ECHO} "${NBITS}"
-}
-
-cidr2mask() {
-	local MASK=""
-	local FULL_OCTETS=$((${1}/8))
-	local PARTIAL_OCTET=$((${1}%8))
-
-	for I in 0 1 2 3
-	do
-		if [ ${I} -lt ${FULL_OCTETS} ]
-		then
-			MASK="${MASK}255"
-		elif [ ${I} -eq ${FULL_OCTETS} ]
-		then
-			MASK="${MASK}$((256-(1<<(8-${PARTIAL_OCTET}))))"
-		else
-			MASK="${MASK}0"
-		fi  
-		${TEST} ${I} -lt 3 && MASK="${MASK}."
-	done
-
-	${ECHO} ${MASK}
-}
-
-##
-# retrieve interfaces. I prefer using ip if it is
-# available, else I fallback to ifconfig... don't know
-# how to retrieve this information on other systems.
-#
-get_if_data() {
-	if [ ${IP} ]
-	then
-		eval $(${IP} -o link | ${AWK} '{
-			sub(/:/,"",$1);
-			no=$1;
-			sub(/:/,"",$2);
-			name=$2;
-			for (i=3; i<NF; i++) {
-				if ($i == "state") {
-					i++; state=$i
-				}
-				if ($i ~ /link/) {
-					i++; mac=$i;
-					classes=classes mac " "
-				}
-			}
-			print "IF" no "_NAME=" name ";IF" no "_STATE=" state ";IF" no "_MAC=" mac ";";
-			if ("UP" == state) classes=classes mac " "
-		}
-		BEGIN {
-			classes=""
-		}
-		END {
-			print "CLASSES=\"${CLASSES}" classes " \";";
-			print "NINTERFACES=" FNR ";"
-		}')
-
-		eval $(${IP} -o addr | ${AWK} '{
-			sub(/:/,"",$1);
-			no=$1;
-			if ($3 == "inet") {
-				sub(/[\/%].*/,"",$4);
-				print "IF" no "_IPV4=\"${IF" no "_IPV4}" $4 " \";";
-				classes=classes $4 " "
-			}
-			if ($3 == "inet6") {
-				sub(/[\/%].*/,"",$4);
-				print "IF" no "_IPV6=\"${IF" no "_IPV6}" $4 " \";";
-				classes=classes $4 " "
-			}
-		}
-		BEGIN {
-			classes=""
-		}
-		END {
-			print "CLASSES=\"${CLASSES}" classes " \";"
-		}')
-	else
-		if [ ${IFCONFIG} ]
-		then
-			#eval $(${IFCONFIG} -a | ${AWK} '{
-			eval $(ifconfig -a | awk '
-			/ether/ { mac=$2 }
-			/inet / { ipv4=ipv4 $2 " " }
-			/inet6/ { ipv6=ipv6 $2 " " }
-			/^[^ \t]/ {
-				if ("" != ipv4 || "" != ipv6) state="UP"; else state="DOWN";
-				if ("" != name) {
-					print "IF" no "_NAME=" name ";IF" no "_STATE=" state ";IF" no "_MAC=" mac ";" \
-						"IF" no "_IPV4=\"${IF" no "_IPV4}" ipv4 " \";" \
-						"IF" no "_IPV6=\"${IF" no "_IPV6}" ipv6 " \";";
-					no++;
-				}
-				ipv4=ipv6="";
-				sub(/:/,"",$1);
-				name=$1
-			}
-			BEGIN {
-				no=1;
-			}
-			END {
-				if ("" != ipv4 || "" != ipv6) state="UP"; else state="DOWN";
-				print "IF" no "_NAME=" name ";IF" no "_STATE=" state ";IF" no "_MAC=" mac ";" \
-					"IF" no "_IPV4=\"${IF" no "_IPV4}" ipv4 " \";" \
-					"IF" no "_IPV6=\"${IF" no "_IPV6}" ipv6 " \";";
-				print "NINTERFACES=" no
-			}')
-		else
-			${LOGGER} -p local0.warn 'Found no way to retrieve interface information.'
-		fi
-	fi
-}
+. ./utils.sh
 
 ##
-# start guessing the system type
-# 1. get informations via uname
+# start guessing the system type via uname and export it.
 #
 get_host_info() {
 	OS="$(${UNAME} -o)"
@@ -159,6 +18,8 @@ get_host_info() {
 	HOSTNAME="$(${UNAME} -n)"
 	CLASSES="$(${ECHO} -e "${OS}\n${KERNEL}\n${VERSION}\n${PLATFORM}\n${HOSTNAME}" |\
 		${SORT} -u | ${TR} "\n" " ")"
+
+	export OS KERNEL VERSION PLATFORM HOSTNAME CLASSES
 }
 
 ##
@@ -186,10 +47,7 @@ get_host_info() {
 # the file.
 #
 get_dist_info() {
-	if [ -z "${KERNEL}" ]
-	then
-		get_host_info
-	fi
+	[ -z "${KERNEL}" ] && get_host_info
 
 	if [ "Linux" = "${KERNEL}" ]
 	then
@@ -229,7 +87,7 @@ get_dist_info() {
 
 			for DIR in ${FILES}
 			do
-				${TEST} -f ${DIR} || CHK=$((CHK&~CUR))
+				[ -f ${DIR} ] || CHK=$((CHK&~CUR))
 			done
 
 			CUR=$((CUR*2))
@@ -237,16 +95,16 @@ get_dist_info() {
 
 		DIST="Unknown"
 
-		${TEST} ${CHK} -eq ${SUSE}      && DIST="Suse"
-		${TEST} ${CHK} -eq ${REDHAT}    && DIST="Redhat"
-		${TEST} ${CHK} -eq ${FEDORA}    && DIST="Fedora"
-		${TEST} ${CHK} -eq ${SLACKWARE} && DIST="Slakware"
-		${TEST} ${CHK} -eq ${DEBIAN}    && DIST="Debian"
-		${TEST} ${CHK} -eq ${MANDRAKE}  && DIST="Mandrake"
-		${TEST} ${CHK} -eq ${YELLOWDOG} && DIST="Yellowdog"
-		${TEST} ${CHK} -eq ${SUNJDS}    && DIST="Sun"
-		${TEST} ${CHK} -eq ${GENTOO}    && DIST="Gentoo"
-		${TEST} ${CHK} -eq ${SOLARIS}   && DIST="Solaris"
+		[ ${CHK} -eq ${SUSE} ]      && DIST="Suse"
+		[ ${CHK} -eq ${REDHAT} ]    && DIST="Redhat"
+		[ ${CHK} -eq ${FEDORA} ]    && DIST="Fedora"
+		[ ${CHK} -eq ${SLACKWARE} ] && DIST="Slakware"
+		[ ${CHK} -eq ${DEBIAN} ]    && DIST="Debian"
+		[ ${CHK} -eq ${MANDRAKE} ]  && DIST="Mandrake"
+		[ ${CHK} -eq ${YELLOWDOG} ] && DIST="Yellowdog"
+		[ ${CHK} -eq ${SUNJDS} ]    && DIST="Sun"
+		[ ${CHK} -eq ${GENTOO} ]    && DIST="Gentoo"
+		[ ${CHK} -eq ${SOLARIS} ]   && DIST="Solaris"
 
 		if [ 'Unknown' != "${DIST}" ]
 		then
@@ -257,59 +115,14 @@ get_dist_info() {
 	else
 		DIST="${OS}"
 	fi
-}
 
-##
-# Here now starts the usage of the functions defined above.
-#
-
-##
-# first specify some programs
-#
-WHICH="/usr/bin/which"
-UNAME="$(${WHICH} uname)"
-TEST="$(${WHICH} test)"
-GREP="$(${WHICH} grep)"
-AWK="$(${WHICH} awk)"
-ECHO="$(${WHICH} echo)"
-SORT="$(${WHICH} sort)"
-TR="$(${WHICH} tr)"
-PRINTF="$(${WHICH} printf)"
-LOGGER="$(${WHICH} logger)"
-IP="$(${WHICH} ip)"
-IFCONFIG="$(${WHICH} ifconfig)"
-
-get_dist_info
-get_if_data
+	export DIST CLASSES
+}
 
 ##
-# report everysthing
+# autorun this if sourced.
 #
 
-${PRINTF} "%15s : %s\n" "OS" "${OS}"
-${PRINTF} "%15s : %s\n" "KERNEL" "${KERNEL}"
-${PRINTF} "%15s : %s\n" "VERSION" "${VERSION}"
-${PRINTF} "%15s : %s\n" "PLATFORM" "${PLATFORM}"
-${PRINTF} "%15s : %s\n" "DIST" "${DIST}"
-${PRINTF} "%15s : %s\n" "HOSTNAME" "${HOSTNAME}"
-${PRINTF} "%15s : %s\n" "# INTERFACES" "${NINTERFACES}"
-
-NO=1
-while [ ${NO} -le ${NINTERFACES:=0} ]
-do
-	eval printf \"%15s : %s\\\n\" \"IF${NO}_NAME\" \"\${IF${NO}_NAME}\"
-	eval printf \"%15s : %s\\\n\" \"IF${NO}_MAC\" \"\${IF${NO}_MAC}\"
-	eval printf \"%15s : %s\\\n\" \"IF${NO}_STATE\" \"\${IF${NO}_STATE}\"
-	eval printf \"%15s : %s\\\n\" \"IF${NO}_IPV4\" \"\${IF${NO}_IPV4}\"
-	eval printf \"%15s : %s\\\n\" \"IF${NO}_IPV6\" \"\${IF${NO}_IPV6}\"
-	NO=$((NO+1))
-done
-
-${PRINTF} "%15s : %s\n" "CLASSES" "${CLASSES}"
-
-echo
-echo $(mask2cidr 255.255.128.0)
-echo $(cidr2mask 17)
-eval echo \$\(cidr2mask $(mask2cidr 255.255.128.0)\)
+[ -z "${DIST}" ] && get_dist_info
 
 # vim: set ts=4 sw=4:
diff --git a/utils.sh b/utils.sh
new file mode 100755
index 0000000..424712f
--- /dev/null
+++ b/utils.sh
@@ -0,0 +1,97 @@
+#!/bin/dash
+
+##
+# make definitions only when not already defined
+#
+
+command -v filename2symbol >/dev/null
+if [ $? -ne 0 ]
+then
+	filename2symbol() {
+		local SYM="${1}"
+
+		if [ 1 -ne $# ]
+		then
+			logger -p syslog.err 'filename2sybol: missing filename'
+			exit 1
+		fi
+
+		while [ "${SYM}" != "${SYM%/*}" -o "${SYM}" != "${SYM%.*}" ]
+		do
+			if [ "${SYM}" != "${SYM%.*}" ]
+			then
+				SYM="${SYM%%.*}_${SYM#*.}"
+			else
+				SYM="${SYM%%/*}_${SYM#*/}"
+			fi
+		done
+
+		echo "${SYM}"
+	}
+
+	canonify_name() {
+		local FILE="${1}"
+		local DIR="${PWD}"
+
+		# if FILE starts with a / its already canonified
+		if [ "${FILE}" != ${FILE#/} ]
+		then
+			echo "${FILE}"
+			return 0
+		fi
+
+		# simply remove ./ and make a ../ remove a part from pwd
+		while [ "${FILE}" != ${FILE#./} -o "${FILE}" != ${FILE#../} ]
+		do
+			if [ "${FILE}" != ${FILE#./} ]
+			then
+				FILE="${FILE#./}"
+			else
+				FILE="${FILE#../}"
+				DIR="${DIR%/*}"
+			fi
+		done
+
+		echo "${DIR}/${FILE}"
+	}
+
+	include_once() {
+		local FILE="$(canonify_name "${1}")"
+		local SYM="$(filename2symbol "${FILE}")"
+
+		if [ 1 -ne $# ]
+		then
+			logger -p syslog.err 'include_once: missing filename'
+			exit 1
+		fi
+
+		if eval [ -z \"\${SOURCED_${SYM}}\" ]
+		then
+			. ${FILE}
+			eval export SOURCED_${SYM}=\"\${FILE}\"
+		fi
+	}
+
+	##
+	# get and export the locations of used programs and export them
+	# I assume that on every UNIX/shell variant at least [ is globally
+	# available. I will use it throughout all other scripts without
+	# checking for existence.
+	# I also assume through all scripts that eval is available.
+	#
+	[ -z "${WHICH}" ]    && WHICH="/usr/bin/which"
+	[ -z "${UNAME}" ]    && UNAME="$(${WHICH} uname)"
+	[ -z "${GREP}" ]     && GREP="$(${WHICH} grep)"
+	[ -z "${AWK}" ]      && AWK="$(${WHICH} awk)"
+	[ -z "${ECHO}" ]     && ECHO="$(${WHICH} echo)"
+	[ -z "${SORT}" ]     && SORT="$(${WHICH} sort)"
+	[ -z "${TR}" ]       && TR="$(${WHICH} tr)"
+	[ -z "${PRINTF}" ]   && PRINTF="$(${WHICH} printf)"
+	[ -z "${LOGGER}" ]   && LOGGER="$(${WHICH} logger)"
+	[ -z "${IP}" ]       && IP="$(${WHICH} ip)"
+	[ -z "${IFCONFIG}" ] && IFCONFIG="$(${WHICH} ifconfig)"
+
+	export WHICH UNAME GREP AWK ECHO SORT TR PRINTF LOGGER IP IFCONFIG
+fi
+
+# vim: set ts=4 sw=4: