diff --git a/README.md b/README.md
index 071f6e6..d8412cc 100644
--- a/README.md
+++ b/README.md
@@ -109,7 +109,9 @@ Additionally, there may be bundles for display or notification plugins, e.g.:
 /opt/hc/bin/check_health.sh --report
 /opt/hc/bin/check_health.sh --report --last
 /opt/hc/bin/check_health.sh --report --today
+/opt/hc/bin/check_health.sh --report --newer=20180101
 /opt/hc/bin/check_health.sh --report --id=20160704154001 --detail
+
 ```
 
 * **Alerting** on failed health checks:
diff --git a/sources/bin/check_health.sh b/sources/bin/check_health.sh
index 28798a4..123b072 100644
--- a/sources/bin/check_health.sh
+++ b/sources/bin/check_health.sh
@@ -544,11 +544,11 @@ cat << EOT
 Execute/report simple health checks (HC) on UNIX hosts.
 
 Syntax: ${SCRIPT_DIR}/${SCRIPT_NAME} [--help] | [--help-terse] | [--version] |
-    [--list=<needle>] | [--list-core] | [--fix-symlinks] | [--show-stats] | (--archive-all | --disable-all | --enable-all) | [--fix-logs [--with-history]] |
+    [--list=<needle>] | [--list-core] | [--list-include] | [--fix-symlinks] | [--show-stats] | (--archive-all | --disable-all | --enable-all) | [--fix-logs [--with-history]] |
         (--check-host | ((--archive | --check | --enable | --disable | --run [--timeout=<secs>] | --show) --hc=<list_of_checks> [--config-file=<configuration_file>] [hc-args="<arg1,arg2=val,arg3">]))
             [--display=<method>] ([--debug] [--debug-level=<level>]) [--log-healthy] [--no-monitor] [--no-log] [--no-lock] [--flip-rc]
                 [--notify=<method_list>] [--mail-to=<address_list>] [--sms-to=<sms_rcpt> --sms-provider=<name>]
-                    [--report=<method> ( ([--last] | [--today]) | ([(--older|--newer)=<date>] [--reverse] [--id=<fail_id> [--detail]] [--with-history]) ) ]
+                    [--report=<method> [--with-history] ( ([--last] | [--today]) | [(--older|--newer)=<date>] | [--reverse] [--id=<fail_id> [--detail]] )]
 
 EOT
 
@@ -586,6 +586,7 @@ Parameters:
                   - whether the HC plugin requires a configuration file in ${CONFIG_DIR}
                   - whether the HC plugin is scheduled by cron
 --list-core     : show the available core plugins (mail,SMS,...)
+--list-include  : show the available includes/libraries
 --log-healthy   : log/show also passed health checks. By default this is off when the plugin support this feature.
                   (can be overridden by --no-log to disable all logging)
 --mail-to       : list of e-mail address(es) to which an e-mail alert will be send to [requires mail core plugin]
@@ -924,6 +925,16 @@ do
             list_core
             exit 0
             ;;
+        -list-include|--list-include)
+            read_config
+            check_config
+            build_fpath
+            check_core
+            check_shell
+            check_user
+            list_include
+            exit 0
+            ;;
         -log-healthy|--log-healthy)
             ARG_LOG_HEALTHY=1
             ;;
diff --git a/sources/lib/core/include_core.sh b/sources/lib/core/include_core.sh
index 0afde65..83e2408 100644
--- a/sources/lib/core/include_core.sh
+++ b/sources/lib/core/include_core.sh
@@ -23,6 +23,20 @@
 # DO NOT CHANGE THIS FILE UNLESS YOU KNOW WHAT YOU ARE DOING!
 #******************************************************************************
 
+# -----------------------------------------------------------------------------
+# @(#) FUNCTION: version_include_core()
+# DOES: dummy function for version placeholder
+# EXPECTS: n/a
+# RETURNS: 0
+function version_include_core
+{
+typeset _VERSION="2019-03-16"                               # YYYY-MM-DD
+
+print "INFO: $0: ${_VERSION#version_*}"
+
+return 0
+}
+
 # -----------------------------------------------------------------------------
 # @(#) FUNCTION: archive_hc()
 # DOES: archive log entries for a given HC
@@ -1425,7 +1439,6 @@ return ${CRON_COUNT}
 function list_core
 {
 (( ARG_DEBUG > 0 && ARG_DEBUG_LEVEL > 0 )) && set "${DEBUG_OPTS}"
-typeset FACTION="${1}"
 typeset FCONFIG=""
 typeset FDIR=""
 typeset FNAME=""
@@ -1435,17 +1448,14 @@ typeset FSTATE="enabled"     # default
 typeset FFILE=""
 typeset FSCRIPT=""
 typeset HAS_FCONFIG=0
-typeset HC_VERSION=""
 
 # print header
-if [[ "${FACTION}" != "list" ]]
-then
-    # shellcheck disable=SC1117
-    printf "%-30s\t%-8s\t%s\t\t%s\n" "Core plugin" "State" "Version" "Config?"
-    # shellcheck disable=SC2183,SC1117
-    printf "%80s\n" | tr ' ' -
-fi
-print "${FPATH}" | tr ':' '\n' | grep "core$" | sort 2>/dev/null | while read -r FDIR
+# shellcheck disable=SC1117
+printf "%-30s\t%-8s\t%s\t\t%s\n" "Core plugin" "State" "Version" "Config?"
+# shellcheck disable=SC2183,SC1117
+printf "%80s\n" | tr ' ' -
+
+print "${FPATH}" | tr ':' '\n' 2>/dev/null | grep "core$" | sort 2>/dev/null | while read -r FDIR
 do
     # exclude core helper librar(y|ies)
     # shellcheck disable=SC2010
@@ -1489,28 +1499,25 @@ do
 done
 
 # dead link detection
-if [[ "${FACTION}" != "list" ]]
-then
-    print
-    print -n "Dead links: "
-    print "${FPATH}" | tr ':' '\n' | grep "core$" | while read -r FDIR
+print
+print -n "Dead links: "
+print "${FPATH}" | tr ':' '\n' 2>/dev/null | grep "core$" 2>/dev/null | while read -r FDIR
+do
+    # do not use 'find -type l' here!
+    # shellcheck disable=SC2010,SC1117
+    ls ${FDIR} 2>/dev/null | grep -v "\." 2>/dev/null | while read -r FFILE
     do
-        # do not use 'find -type l' here!
-        # shellcheck disable=SC2010,SC1117
-        ls ${FDIR} 2>/dev/null | grep -v "\." | while read -r FFILE
-        do
-            if [[ -h "${FDIR}/${FFILE}" ]] && [[ ! -f "${FDIR}/${FFILE}" ]]
-            then
-                printf "%s " ${FFILE##*/}
-            fi
-        done
+        if [[ -h "${FDIR}/${FFILE}" ]] && [[ ! -f "${FDIR}/${FFILE}" ]]
+        then
+            printf "%s " ${FFILE##*/}
+        fi
     done
-    print
+done
+print
 
-    # show FPATH
-    print
-    print "current FPATH: ${FPATH}"
-fi
+# show FPATH
+print
+print "current FPATH: ${FPATH}"
 
 return 0
 }
@@ -1539,7 +1546,6 @@ typeset FSCRIPT=""
 typeset HAS_FCONFIG=0
 typeset HAS_FHEALTHY=""
 typeset DISABLE_FFILE=""
-typeset HC_VERSION=""
 
 # build search needle
 if [[ -z "${ARG_LIST}" ]]
@@ -1663,11 +1669,11 @@ if [[ "${FACTION}" != "list" ]]
 then
     print
     print -n "Dead links: "
-    print "${FPATH}" | tr ':' '\n' | grep -v "core" | while read -r FDIR
+    print "${FPATH}" | tr ':' '\n' 2>/dev/null | grep -v "core" 2>/dev/null | while read -r FDIR
     do
         # do not use 'find -type l' here!
         # shellcheck disable=SC2010,SC1117
-        ls ${FDIR} 2>/dev/null | grep -v "\." | while read -r FFILE
+        ls ${FDIR} 2>/dev/null | grep -v "\." 2>/dev/null | while read -r FFILE
         do
             if [[ -h "${FDIR}/${FFILE}" ]] && [[ ! -f "${FDIR}/${FFILE}" ]]
             then
@@ -1694,6 +1700,88 @@ fi
 return 0
 }
 
+# -----------------------------------------------------------------------------
+# @(#) FUNCTION: list_include()
+# DOES: find HC include files (libraries)
+# EXPECTS: n/a
+# RETURNS: 0
+# REQUIRES: n/a
+function list_include
+{
+(( ARG_DEBUG > 0 && ARG_DEBUG_LEVEL > 0 )) && set "${DEBUG_OPTS}"
+typeset FDIR=""
+typeset FNAME=""
+typeset FVERSION=""
+typeset FFILE=""
+typeset FSTATE="enabled"     # default
+typeset FSCRIPT=""
+typeset FFUNCTIONS=""
+typeset FFUNCTION=""
+
+# print header
+# shellcheck disable=SC1117
+printf "%-20s\t%-8s\t%12s\t\t%s\n" "Include/libary" "State" "Version" "Functions"
+# shellcheck disable=SC2183,SC1117
+printf "%100s\n" | tr ' ' -
+
+print "${FPATH}" | tr ':' '\n' 2>/dev/null  | grep "core$" 2>/dev/null | sort 2>/dev/null | while read -r FDIR
+do
+    # exclude core helper librar(y|ies)
+    # shellcheck disable=SC2010
+    ls -1 ${FDIR}/*.sh 2>/dev/null | grep "include_" 2>/dev/null | sort 2>/dev/null | while read -r FFILE
+    do
+        # cache script contents in memory
+        FSCRIPT=$(<${FFILE})
+
+        # find function name
+        FNAME=$(print -R "${FSCRIPT}" | grep -E -e "^function[[:space:]].*version_" 2>/dev/null)
+        # look for version string (cut off comments but don't use [:space:] in tr)
+        FVERSION=$(print -R "${FSCRIPT}" | grep '^typeset _VERSION=' 2>/dev/null |\
+            awk 'match($0,/[0-9]+-[0-9]+-[0-9]+/){print substr($0, RSTART, RLENGTH)}' 2>/dev/null)
+
+        # get list of functions
+        FFUNCTIONS=$(print -R "${FSCRIPT}" | grep -E -e "^function[[:space:]]+" 2>/dev/null | awk '{ print $2}' 2>/dev/null)
+
+        # check state (only for unlinked)
+        [[ -h ${FFILE%%.*} ]] || FSTATE="unlinked"
+
+        # show results
+        # shellcheck disable=SC1117
+        printf "%-20s\t%-8s\t%12s\n" \
+            "${FNAME#function version_*}" \
+            "${FSTATE}" \
+            "${FVERSION#typeset _VERSION=*}"
+        print "${FFUNCTIONS}" | while read -r FFUNCTION
+        do
+            printf "%64s%s\n" "" "${FFUNCTION}"
+        done
+    done
+done
+
+# dead link detection
+print
+print -n "Dead links: "
+print "${FPATH}" | tr ':' '\n' 2>/dev/null | grep "core$" 2>/dev/null | while read -r FDIR
+do
+    # do not use 'find -type l' here!
+    # shellcheck disable=SC2010,SC1117
+    ls ${FDIR} 2>/dev/null | grep -v "\." 2>/dev/null | while read -r FFILE
+    do
+        if [[ -h "${FDIR}/${FFILE}" ]] && [[ ! -f "${FDIR}/${FFILE}" ]]
+        then
+            printf "%s " ${FFILE##*/}
+        fi
+    done
+done
+print
+
+# show FPATH
+print
+print "current FPATH: ${FPATH}"
+
+return 0
+}
+
 # -----------------------------------------------------------------------------
 # @(#) FUNCTION: log()
 # DOES: handle messages
diff --git a/sources/lib/core/include_data.sh b/sources/lib/core/include_data.sh
index 1c10c6d..9c6381f 100644
--- a/sources/lib/core/include_data.sh
+++ b/sources/lib/core/include_data.sh
@@ -23,6 +23,20 @@
 # DO NOT CHANGE THIS FILE UNLESS YOU KNOW WHAT YOU ARE DOING!
 #******************************************************************************
 
+# -----------------------------------------------------------------------------
+# @(#) FUNCTION: version_include_core()
+# DOES: dummy function for version placeholder
+# EXPECTS: n/a
+# RETURNS: 0
+function version_include_data
+{
+typeset _VERSION="2019-03-16"                               # YYYY-MM-DD
+
+print "INFO: $0: ${_VERSION#version_*}"
+
+return 0
+}
+
 # -----------------------------------------------------------------------------
 # @(#) FUNCTION: data_get_lvalue_from_config()
 # DOES: get an lvalue from the configuration file
diff --git a/sources/lib/core/include_os.sh b/sources/lib/core/include_os.sh
index 90ad57c..bd916ea 100644
--- a/sources/lib/core/include_os.sh
+++ b/sources/lib/core/include_os.sh
@@ -23,6 +23,20 @@
 # DO NOT CHANGE THIS FILE UNLESS YOU KNOW WHAT YOU ARE DOING!
 #******************************************************************************
 
+# -----------------------------------------------------------------------------
+# @(#) FUNCTION: version_include_core()
+# DOES: dummy function for version placeholder
+# EXPECTS: n/a
+# RETURNS: 0
+function version_include_os
+{
+typeset _VERSION="2019-03-16"                               # YYYY-MM-DD
+
+print "INFO: $0: ${_VERSION#version_*}"
+
+return 0
+}
+
 # -----------------------------------------------------------------------------
 # @(#) FUNCTION: linux_get_distro()
 # DOES: get Linux distribution name & version, sets $LINUX_DISTRO & $LINUX_RELEASE
@@ -128,7 +142,7 @@ check_platform 'Linux' || {
     return 1
 }
 
-_CRM_BIN="$(which crm 2>/dev/null)"
+_CRM_BIN="$(command -v crm 2>/dev/null)"
 if [[ -x ${_CRM_BIN} && -n "${_CRM_BIN}" ]]
 then
     # check for active
@@ -164,7 +178,7 @@ check_platform 'Linux' || {
     return 1
 }
 
-_DOCKER_BIN="$(which docker 2>/dev/null)"
+_DOCKER_BIN="$(command -v docker 2>/dev/null)"
 if [[ -x ${_DOCKER_BIN} && -n "${_DOCKER_BIN}" ]]
 then
     # check for active
@@ -200,7 +214,7 @@ check_platform 'Linux' || {
     return 1
 }
 
-_NMCLI_BIN="$(which nmcli 2>/dev/null)"
+_NMCLI_BIN="$(command -v nmcli 2>/dev/null)"
 if [[ -x ${_NMCLI_BIN} && -n "${_NMCLI_BIN}" ]]
 then
     # check for active
diff --git a/sources/lib/core/notify_mail.sh b/sources/lib/core/notify_mail.sh
index 9d2f449..f780500 100644
--- a/sources/lib/core/notify_mail.sh
+++ b/sources/lib/core/notify_mail.sh
@@ -80,13 +80,13 @@ _HC_STDERR_LOG_SHORT="${HC_STDERR_LOG##*/}"
 case "${OS_NAME}" in
     "Linux")
         # prefer mutt :-)
-        _MUTT_BIN="$(which mutt 2>/dev/null)"
+        _MUTT_BIN="$(command -v mutt 2>/dev/null)"
         if [[ -x ${_MUTT_BIN} ]] && [[ -n "${_MUTT_BIN}" ]]
         then
             _MAIL_METHOD="mutt"
         else
             # prefer mailx next
-            _MAILX_BIN="$(which mailx 2>/dev/null)"
+            _MAILX_BIN="$(command -v mailx 2>/dev/null)"
             if [[ -x ${_MAILX_BIN} ]] && [[ -n "${_MAILX_BIN}" ]]
             then
                 _MAIL_METHOD="mailx"
@@ -103,13 +103,13 @@ esac
 if [[ "${_MAIL_METHOD}" = "sendmail" ]]
 then
     # find 'sendmail'
-    _SENDMAIL_BIN="$(which sendmail 2>/dev/null)"
+    _SENDMAIL_BIN="$(command -v sendmail 2>/dev/null)"
     if [[ ! -x ${_SENDMAIL_BIN} ]] || [[ -z "${_SENDMAIL_BIN}" ]]
     then
         die "unable to send e-mail - sendmail is not installed here"
     fi
     # find 'uuencode'
-    _UUENCODE_BIN="$(which uuencode 2>/dev/null)"
+    _UUENCODE_BIN="$(command -v uuencode 2>/dev/null)"
     if [[ ! -x ${_UUENCODE_BIN} ]] || [[ -z "${_UUENCODE_BIN}" ]]
     then
         die "unable to send e-mail - uuencode is not installed here"
diff --git a/sources/lib/core/notify_sms.sh b/sources/lib/core/notify_sms.sh
index 7201c85..92d28b3 100644
--- a/sources/lib/core/notify_sms.sh
+++ b/sources/lib/core/notify_sms.sh
@@ -100,7 +100,7 @@ case "${ARG_SMS_PROVIDER}" in
     *kapow*|*KAPOW*|*Kapow*)
         # KAPOW (https://www.kapow.co.uk/)
         # find 'curl'
-        _CURL_BIN="$(which curl 2>/dev/null)"
+        _CURL_BIN="$(command -v curl 2>/dev/null)"
         if [[ -x ${_CURL_BIN} ]] && [[ -n "${_CURL_BIN}" ]]
         then
             _SMS_TEXT=$(print "${_FROM_MSG}: HC ${_SMS_HC} failed, FAIL_ID=${_SMS_FAIL_ID}" | data_encode_url)
diff --git a/sources/lib/core/report_std.sh b/sources/lib/core/report_std.sh
index f0d6e64..d7289b6 100644
--- a/sources/lib/core/report_std.sh
+++ b/sources/lib/core/report_std.sh
@@ -30,7 +30,7 @@
 function report_std
 {
 # ------------------------- CONFIGURATION starts here -------------------------
-typeset _VERSION="2019-03-18"                               # YYYY-MM-DD
+typeset _VERSION="2019-03-16"                               # YYYY-MM-DD
 typeset _SUPPORTED_PLATFORMS="AIX,HP-UX,Linux"              # uname -s match
 # ------------------------- CONFIGURATION ends here ---------------------------
 
diff --git a/sources/lib/platform/aix/check_aix_file_change.sh b/sources/lib/platform/aix/check_aix_file_change.sh
index defd768..f75f83e 100644
--- a/sources/lib/platform/aix/check_aix_file_change.sh
+++ b/sources/lib/platform/aix/check_aix_file_change.sh
@@ -28,6 +28,7 @@
 # @(#) 2018-11-18: do not trap on signal 0 [Patrick Van der Veken]
 # @(#) 2019-01-24: arguments fix [Patrick Van der Veken]
 # @(#) 2019-03-09: added support for --log-healthy [Patrick Van der Veken]
+# @(#) 2019-03-16: replace 'which' [Patrick Van der Veken]
 # -----------------------------------------------------------------------------
 # DO NOT CHANGE THIS FILE UNLESS YOU KNOW WHAT YOU ARE DOING!
 #******************************************************************************
@@ -37,7 +38,7 @@ function check_aix_file_change
 {
 # ------------------------- CONFIGURATION starts here -------------------------
 typeset _CONFIG_FILE="${CONFIG_DIR}/$0.conf"
-typeset _VERSION="2019-03-09"                           # YYYY-MM-DD
+typeset _VERSION="2019-03-16"                           # YYYY-MM-DD
 typeset _SUPPORTED_PLATFORMS="Linux"                    # uname -s match
 # ------------------------- CONFIGURATION ends here ---------------------------
 
@@ -140,9 +141,9 @@ else
 fi
 
 # check for checksum tools
-_OPENSSL_BIN="$(which openssl 2>>${HC_STDERR_LOG})"
+_OPENSSL_BIN="$(command -v openssl 2>>${HC_STDERR_LOG})"
 [[ -x ${_OPENSSL_BIN} && -n "${_OPENSSL_BIN}" ]] && _HAS_OPENSSL=1
-_CKSUM_BIN="$(which cksum 2>>${HC_STDERR_LOG})"
+_CKSUM_BIN="$(command -v cksum 2>>${HC_STDERR_LOG})"
 [[ -x ${_CKSUM_BIN} && -n "${_CKSUM_BIN}" ]] && _HAS_CKSUM=1
 # prefer openssl (for sha256)
 if (( _HAS_OPENSSL == 1 ))
diff --git a/sources/lib/platform/exadata/check_exadata_zfs_logs.sh b/sources/lib/platform/exadata/check_exadata_zfs_logs.sh
index 46e23b1..1b85399 100644
--- a/sources/lib/platform/exadata/check_exadata_zfs_logs.sh
+++ b/sources/lib/platform/exadata/check_exadata_zfs_logs.sh
@@ -24,6 +24,7 @@
 #
 # @(#) HISTORY:
 # @(#) 2019-02-18: initial version [Patrick Van der Veken]
+# @(#) 2019-03-16: replace 'which' [Patrick Van der Veken]
 # -----------------------------------------------------------------------------
 # DO NOT CHANGE THIS FILE UNLESS YOU KNOW WHAT YOU ARE DOING!
 #******************************************************************************
@@ -33,7 +34,7 @@ function check_exadata_zfs_logs
 {
 # ------------------------- CONFIGURATION starts here -------------------------
 typeset _CONFIG_FILE="${CONFIG_DIR}/$0.conf"
-typeset _VERSION="2019-02-18"                           # YYYY-MM-DD
+typeset _VERSION="2019-03-16"                           # YYYY-MM-DD
 typeset _SUPPORTED_PLATFORMS="Linux"                    # uname -s match
 # ------------------------- CONFIGURATION ends here ---------------------------
 
@@ -134,7 +135,7 @@ else
 fi
 
 # check ssh
-_SSH_BIN="$(which ssh 2>>${HC_STDERR_LOG})"
+_SSH_BIN="$(command -v ssh 2>>${HC_STDERR_LOG})"
 if [[ ! -x ${_SSH_BIN} || -z "${_SSH_BIN}" ]]
 then
     warn "SSH is not installed here"
diff --git a/sources/lib/platform/exadata/check_exadata_zfs_services.sh b/sources/lib/platform/exadata/check_exadata_zfs_services.sh
index a4913e1..1c04e2a 100644
--- a/sources/lib/platform/exadata/check_exadata_zfs_services.sh
+++ b/sources/lib/platform/exadata/check_exadata_zfs_services.sh
@@ -24,6 +24,7 @@
 #
 # @(#) HISTORY:
 # @(#) 2019-02-18: initial version [Patrick Van der Veken]
+# @(#) 2019-03-16: replace 'which' [Patrick Van der Veken]
 # -----------------------------------------------------------------------------
 # DO NOT CHANGE THIS FILE UNLESS YOU KNOW WHAT YOU ARE DOING!
 #******************************************************************************
@@ -33,7 +34,7 @@ function check_exadata_zfs_services
 {
 # ------------------------- CONFIGURATION starts here -------------------------
 typeset _CONFIG_FILE="${CONFIG_DIR}/$0.conf"
-typeset _VERSION="2019-02-18"                           # YYYY-MM-DD
+typeset _VERSION="2019-03-16"                           # YYYY-MM-DD
 typeset _SUPPORTED_PLATFORMS="Linux"                    # uname -s match
 # usage query script -- DO NOT CHANGE --
 # svc1:online
@@ -137,7 +138,7 @@ else
 fi
 
 # check ssh
-_SSH_BIN="$(which ssh 2>>${HC_STDERR_LOG})"
+_SSH_BIN="$(command -v ssh 2>>${HC_STDERR_LOG})"
 if [[ ! -x ${_SSH_BIN} || -z "${_SSH_BIN}" ]]
 then
     warn "SSH is not installed here"
diff --git a/sources/lib/platform/exadata/check_exadata_zfs_share_replication.sh b/sources/lib/platform/exadata/check_exadata_zfs_share_replication.sh
index 02e975b..ff9f690 100644
--- a/sources/lib/platform/exadata/check_exadata_zfs_share_replication.sh
+++ b/sources/lib/platform/exadata/check_exadata_zfs_share_replication.sh
@@ -25,6 +25,7 @@
 # @(#) HISTORY:
 # @(#) 2019-02-18: initial version [Patrick Van der Veken]
 # @(#) 2019-02-19: fix for <unknown> replication value [Patrick Van der Veken]
+# @(#) 2019-03-16: replace 'which' [Patrick Van der Veken]
 # -----------------------------------------------------------------------------
 # DO NOT CHANGE THIS FILE UNLESS YOU KNOW WHAT YOU ARE DOING!
 #******************************************************************************
@@ -34,7 +35,7 @@ function check_exadata_zfs_share_replication
 {
 # ------------------------- CONFIGURATION starts here -------------------------
 typeset _CONFIG_FILE="${CONFIG_DIR}/$0.conf"
-typeset _VERSION="2019-02-19"                           # YYYY-MM-DD
+typeset _VERSION="2019-03-16"                           # YYYY-MM-DD
 typeset _SUPPORTED_PLATFORMS="Linux"                    # uname -s match
 # replication query script -- DO NOT CHANGE --
 # prj1/share1:true:idle:success:111
@@ -148,7 +149,7 @@ else
 fi
 
 # check ssh
-_SSH_BIN="$(which ssh 2>>${HC_STDERR_LOG})"
+_SSH_BIN="$(command -v ssh 2>>${HC_STDERR_LOG})"
 if [[ ! -x ${_SSH_BIN} || -z "${_SSH_BIN}" ]]
 then
     warn "SSH is not installed here"
diff --git a/sources/lib/platform/exadata/check_exadata_zfs_share_usage.sh b/sources/lib/platform/exadata/check_exadata_zfs_share_usage.sh
index 176c800..76d8996 100644
--- a/sources/lib/platform/exadata/check_exadata_zfs_share_usage.sh
+++ b/sources/lib/platform/exadata/check_exadata_zfs_share_usage.sh
@@ -24,6 +24,7 @@
 #
 # @(#) HISTORY:
 # @(#) 2019-02-18: initial version [Patrick Van der Veken]
+# @(#) 2019-03-16: replace 'which' [Patrick Van der Veken]
 # -----------------------------------------------------------------------------
 # DO NOT CHANGE THIS FILE UNLESS YOU KNOW WHAT YOU ARE DOING!
 #******************************************************************************
@@ -33,7 +34,7 @@ function check_exadata_zfs_share_usage
 {
 # ------------------------- CONFIGURATION starts here -------------------------
 typeset _CONFIG_FILE="${CONFIG_DIR}/$0.conf"
-typeset _VERSION="2019-02-18"                           # YYYY-MM-DD
+typeset _VERSION="2019-03-16"                           # YYYY-MM-DD
 typeset _SUPPORTED_PLATFORMS="Linux"                    # uname -s match
 # usage query script -- DO NOT CHANGE --
 # prj1:share1:16
@@ -155,7 +156,7 @@ else
 fi
 
 # check ssh
-_SSH_BIN="$(which ssh 2>>${HC_STDERR_LOG})"
+_SSH_BIN="$(command -v ssh 2>>${HC_STDERR_LOG})"
 if [[ ! -x ${_SSH_BIN} || -z "${_SSH_BIN}" ]]
 then
     warn "SSH is not installed here"
diff --git a/sources/lib/platform/hp-ux/check_hpux_cron_status.sh b/sources/lib/platform/hp-ux/check_hpux_cron_status.sh
index 8358171..a1af81b 100644
--- a/sources/lib/platform/hp-ux/check_hpux_cron_status.sh
+++ b/sources/lib/platform/hp-ux/check_hpux_cron_status.sh
@@ -24,6 +24,7 @@
 # @(#) HISTORY:
 # @(#) 2018-02-08: initial version [Patrick Van der Veken]µ
 # @(#) 2018-02-13: fix to avoid log check if cron is not active [Patrick Van der Veken]
+# @(#) 2019-03-16: replace 'which' [Patrick Van der Veken]
 # -----------------------------------------------------------------------------
 # DO NOT CHANGE THIS FILE UNLESS YOU KNOW WHAT YOU ARE DOING!
 #******************************************************************************
@@ -34,7 +35,7 @@ function check_hpux_cron_status
 # ------------------------- CONFIGURATION starts here -------------------------
 typeset _CRON_LOG_FILE="/var/adm/cron/log"
 typeset _WAIT_TIME=10
-typeset _VERSION="2019-02-13"                           # YYYY-MM-DD
+typeset _VERSION="2019-02-16"                           # YYYY-MM-DD
 typeset _SUPPORTED_PLATFORMS="HP-UX"                    # uname -s match
 # ------------------------- CONFIGURATION ends here ---------------------------
 
@@ -98,7 +99,7 @@ then
 fi
 
 # ---- log state ----
-_AT_BIN="$(which at 2>>${HC_STDERR_LOG})"
+_AT_BIN="$(command -v at 2>>${HC_STDERR_LOG})"
 if [[ -x ${_AT_BIN} && -n "${_AT_BIN}" ]]
 then
     # start test job
diff --git a/sources/lib/platform/hp-ux/check_hpux_file_change.sh b/sources/lib/platform/hp-ux/check_hpux_file_change.sh
index 88da27d..bbb8e31 100644
--- a/sources/lib/platform/hp-ux/check_hpux_file_change.sh
+++ b/sources/lib/platform/hp-ux/check_hpux_file_change.sh
@@ -28,6 +28,7 @@
 # @(#) 2018-11-18: do not trap on signal 0 [Patrick Van der Veken]
 # @(#) 2019-01-24: arguments fix [Patrick Van der Veken]
 # @(#) 2019-03-09: added support for --log-healthy [Patrick Van der Veken]
+# @(#) 2019-03-16: replace 'which' [Patrick Van der Veken]
 # -----------------------------------------------------------------------------
 # DO NOT CHANGE THIS FILE UNLESS YOU KNOW WHAT YOU ARE DOING!
 #******************************************************************************
@@ -37,7 +38,7 @@ function check_hpux_file_change
 {
 # ------------------------- CONFIGURATION starts here -------------------------
 typeset _CONFIG_FILE="${CONFIG_DIR}/$0.conf"
-typeset _VERSION="2019-03-09"                           # YYYY-MM-DD
+typeset _VERSION="2019-03-16"                           # YYYY-MM-DD
 typeset _SUPPORTED_PLATFORMS="HP-UX"                    # uname -s match
 # ------------------------- CONFIGURATION ends here ---------------------------
 
@@ -140,9 +141,9 @@ else
 fi
 
 # check for checksum tools
-_OPENSSL_BIN="$(which openssl 2>>${HC_STDERR_LOG})"
+_OPENSSL_BIN="$(command -v openssl 2>>${HC_STDERR_LOG})"
 [[ -x ${_OPENSSL_BIN} && -n "${_OPENSSL_BIN}" ]] && _HAS_OPENSSL=1
-_CKSUM_BIN="$(which cksum 2>>${HC_STDERR_LOG})"
+_CKSUM_BIN="$(command -v cksum 2>>${HC_STDERR_LOG})"
 [[ -x ${_CKSUM_BIN} && -n "${_CKSUM_BIN}" ]] && _HAS_CKSUM=1
 # prefer openssl (for sha256)
 if (( _HAS_OPENSSL == 1 ))
diff --git a/sources/lib/platform/hp-ux/check_hpux_httpd_status.sh b/sources/lib/platform/hp-ux/check_hpux_httpd_status.sh
index 93d74f9..3817308 100644
--- a/sources/lib/platform/hp-ux/check_hpux_httpd_status.sh
+++ b/sources/lib/platform/hp-ux/check_hpux_httpd_status.sh
@@ -26,6 +26,7 @@
 # @(#) 2018-10-28: fixed (linter) errors [Patrick Van der Veken]
 # @(#) 2019-01-24: arguments fix [Patrick Van der Veken]
 # @(#) 2019-03-09: added support for --log-healthy [Patrick Van der Veken]
+# @(#) 2019-03-16: replace 'which' [Patrick Van der Veken]
 # -----------------------------------------------------------------------------
 # DO NOT CHANGE THIS FILE UNLESS YOU KNOW WHAT YOU ARE DOING!
 #******************************************************************************
@@ -35,7 +36,7 @@ function check_hpux_httpd_status
 {
 # ------------------------- CONFIGURATION starts here -------------------------
 typeset _HTTPD_PID_FILE="/var/run/httpd/httpd.pid"
-typeset _VERSION="2019-03-09"                           # YYYY-MM-DD
+typeset _VERSION="2019-03-16"                           # YYYY-MM-DD
 typeset _SUPPORTED_PLATFORMS="HP-UX"                    # uname -s match
 # ------------------------- CONFIGURATION ends here ---------------------------
 
@@ -117,7 +118,7 @@ then
 fi
 
 # ---- config state ----
-_HTTPD_BIN="$(which httpd 2>>${HC_STDERR_LOG})"
+_HTTPD_BIN="$(command -v httpd 2>>${HC_STDERR_LOG})"
 if [[ -x ${_HTTPD_BIN} && -n "${_HTTPD_BIN}" ]]
 then
     # validate main configuration
diff --git a/sources/lib/platform/hp-ux/check_hpux_named_status.sh b/sources/lib/platform/hp-ux/check_hpux_named_status.sh
index 31c09f4..cae3211 100644
--- a/sources/lib/platform/hp-ux/check_hpux_named_status.sh
+++ b/sources/lib/platform/hp-ux/check_hpux_named_status.sh
@@ -25,6 +25,7 @@
 # @(#) 2017-01-07: initial version [Patrick Van der Veken]
 # @(#) 2019-01-24: arguments fix [Patrick Van der Veken]
 # @(#) 2019-03-09: added support for --log-healthy [Patrick Van der Veken]
+# @(#) 2019-03-16: replace 'which' [Patrick Van der Veken]
 # -----------------------------------------------------------------------------
 # DO NOT CHANGE THIS FILE UNLESS YOU KNOW WHAT YOU ARE DOING!
 #******************************************************************************
@@ -34,7 +35,7 @@ function check_hpux_named_status
 {
 # ------------------------- CONFIGURATION starts here -------------------------
 typeset _NAMED_PID_FILE="/var/run/named/named.pid"
-typeset _VERSION="2019-03-09"                           # YYYY-MM-DD
+typeset _VERSION="2019-03-16"                           # YYYY-MM-DD
 typeset _SUPPORTED_PLATFORMS="HP-UX"                    # uname -s match
 # ------------------------- CONFIGURATION ends here ---------------------------
 
@@ -116,7 +117,7 @@ then
 fi
 
 # ---- config state ----
-_NAMED_CHECKCONF_BIN="$(which named-checkconf 2>>${HC_STDERR_LOG})"
+_NAMED_CHECKCONF_BIN="$(command -v named-checkconf 2>>${HC_STDERR_LOG})"
 if [[ -x ${_NAMED_CHECKCONF_BIN} && -n "${_NAMED_CHECKCONF_BIN}" ]]
 then
     # validate main configuration and test load zones
diff --git a/sources/lib/platform/hp-ux/check_hpux_postfix_status.sh b/sources/lib/platform/hp-ux/check_hpux_postfix_status.sh
index aa0bca7..c509746 100644
--- a/sources/lib/platform/hp-ux/check_hpux_postfix_status.sh
+++ b/sources/lib/platform/hp-ux/check_hpux_postfix_status.sh
@@ -25,6 +25,7 @@
 # @(#) 2016-12-01: initial version [Patrick Van der Veken]
 # @(#) 2019-01-24: arguments fix [Patrick Van der Veken]
 # @(#) 2019-03-09: added support for --log-healthy [Patrick Van der Veken]
+# @(#) 2019-03-16: replace 'which' [Patrick Van der Veken]
 # -----------------------------------------------------------------------------
 # DO NOT CHANGE THIS FILE UNLESS YOU KNOW WHAT YOU ARE DOING!
 #******************************************************************************
@@ -71,7 +72,7 @@ else
     log "not logging/showing passed health checks"
 fi
 
-_POSTFIX_BIN="$(which postfix 2>>${HC_STDERR_LOG})"
+_POSTFIX_BIN="$(command -v postfix 2>>${HC_STDERR_LOG})"
 if [[ -x ${_POSTFIX_BIN} && -n "${_POSTFIX_BIN}" ]]
 then
     ${_POSTFIX_BIN} status >>${HC_STDOUT_LOG} 2>>${HC_STDERR_LOG}
diff --git a/sources/lib/platform/hp-ux/check_hpux_syslogd_status.sh b/sources/lib/platform/hp-ux/check_hpux_syslogd_status.sh
index 40ec490..1bacdda 100644
--- a/sources/lib/platform/hp-ux/check_hpux_syslogd_status.sh
+++ b/sources/lib/platform/hp-ux/check_hpux_syslogd_status.sh
@@ -25,6 +25,7 @@
 # @(#) 2018-02-08: initial version [Patrick Van der Veken]
 # @(#) 2018-02-13: fix to avoid log check if syslogd is not active [Patrick Van der Veken]
 # @(#) 2019-03-09: text updates [Patrick Van der Veken]
+# @(#) 2019-03-16: replace 'which' [Patrick Van der Veken]
 # -----------------------------------------------------------------------------
 # DO NOT CHANGE THIS FILE UNLESS YOU KNOW WHAT YOU ARE DOING!
 #******************************************************************************
@@ -35,7 +36,7 @@ function check_hpux_syslogd_status
 # ------------------------- CONFIGURATION starts here -------------------------
 typeset _SYSLOGD_PID_FILE="/var/run/syslog.pid"
 typeset _SYSLOGD_LOG_FILE="/var/adm/syslog.log"
-typeset _VERSION="2019-03-09"                           # YYYY-MM-DD
+typeset _VERSION="2019-03-16"                           # YYYY-MM-DD
 typeset _SUPPORTED_PLATFORMS="HP-UX"                    # uname -s match
 # ------------------------- CONFIGURATION ends here ---------------------------
 
@@ -120,7 +121,7 @@ then
 fi
 
 # ---- log state ----
-_LOGGER_BIN="$(which logger 2>>${HC_STDERR_LOG})"
+_LOGGER_BIN="$(command -v logger 2>>${HC_STDERR_LOG})"
 if [[ -x ${_LOGGER_BIN} && -n "${_LOGGER_BIN}" ]]
 then
     # write test entry
diff --git a/sources/lib/platform/linux/check_linux_burp_backup.sh b/sources/lib/platform/linux/check_linux_burp_backup.sh
index 61eba69..761a714 100644
--- a/sources/lib/platform/linux/check_linux_burp_backup.sh
+++ b/sources/lib/platform/linux/check_linux_burp_backup.sh
@@ -33,6 +33,7 @@
 # @(#) 2019-03-09: changed format of stanzas in configuration file &
 # @(#)             added support for --log-healthy [Patrick Van der Veken]
 # @(#) 2019-03-10: fix for burp v2
+# @(#) 2019-03-16: replace 'which' [Patrick Van der Veken]
 # -----------------------------------------------------------------------------
 # DO NOT CHANGE THIS FILE UNLESS YOU KNOW WHAT YOU ARE DOING!
 #******************************************************************************
@@ -44,7 +45,7 @@ function check_linux_burp_backup
 typeset _BURP_SERVER_CONFIG_FILE="/etc/burp/burp-server.conf"
 typeset _BURP_CLIENT_CONFIG_FILE="/etc/burp/burp.conf"
 typeset _CONFIG_FILE="${CONFIG_DIR}/$0.conf"
-typeset _VERSION="2019-03-10"                           # YYYY-MM-DD
+typeset _VERSION="2019-03-16"                           # YYYY-MM-DD
 typeset _SUPPORTED_PLATFORMS="Linux"                    # uname -s match
 # ------------------------- CONFIGURATION ends here ---------------------------
 
@@ -129,7 +130,7 @@ then
 fi
 
 # find burp
-_BURP_BIN="$(which burp 2>/dev/null)"
+_BURP_BIN="$(command -v burp 2>/dev/null)"
 if [[ ! -x ${_BURP_BIN} || -z "${_BURP_BIN}" ]]
 then
     warn "burp is not installed here"
diff --git a/sources/lib/platform/linux/check_linux_es_status.sh b/sources/lib/platform/linux/check_linux_es_status.sh
index 8514954..0bbe7bb 100644
--- a/sources/lib/platform/linux/check_linux_es_status.sh
+++ b/sources/lib/platform/linux/check_linux_es_status.sh
@@ -23,6 +23,7 @@
 #
 # @(#) HISTORY:
 # @(#) 2019-03-09: initial version [Patrick Van der Veken]
+# @(#) 2019-03-16: replace 'which' [Patrick Van der Veken]
 # -----------------------------------------------------------------------------
 # DO NOT CHANGE THIS FILE UNLESS YOU KNOW WHAT YOU ARE DOING!
 #******************************************************************************
@@ -32,7 +33,7 @@ function check_linux_es_status
 {
 # ------------------------- CONFIGURATION starts here -------------------------
 typeset _CONFIG_FILE="${CONFIG_DIR}/$0.conf"
-typeset _VERSION="2019-03-09"                           # YYYY-MM-DD
+typeset _VERSION="2019-03-16"                           # YYYY-MM-DD
 typeset _SUPPORTED_PLATFORMS="Linux"                    # uname -s match
 # ------------------------- CONFIGURATION ends here ---------------------------
 
@@ -103,7 +104,7 @@ else
 fi
 
 # check curl
-_CURL_BIN="$(which curl 2>>${HC_STDERR_LOG})"
+_CURL_BIN="$(command -v curl 2>>${HC_STDERR_LOG})"
 if [[ ! -x ${_CURL_BIN} || -z "${_CURL_BIN}" ]]
 then
     warn "curl is not installed here"
diff --git a/sources/lib/platform/linux/check_linux_file_change.sh b/sources/lib/platform/linux/check_linux_file_change.sh
index fb6f2a4..e3172d9 100644
--- a/sources/lib/platform/linux/check_linux_file_change.sh
+++ b/sources/lib/platform/linux/check_linux_file_change.sh
@@ -29,6 +29,7 @@
 # @(#) 2018-11-18: do not trap on signal 0 [Patrick Van der Veken]
 # @(#) 2019-01-24: arguments fix [Patrick Van der Veken]
 # @(#) 2019-03-09: added support for --log-healthy [Patrick Van der Veken]
+# @(#) 2019-03-16: replace 'which' [Patrick Van der Veken]
 # -----------------------------------------------------------------------------
 # DO NOT CHANGE THIS FILE UNLESS YOU KNOW WHAT YOU ARE DOING!
 #******************************************************************************
@@ -38,7 +39,7 @@ function check_linux_file_change
 {
 # ------------------------- CONFIGURATION starts here -------------------------
 typeset _CONFIG_FILE="${CONFIG_DIR}/$0.conf"
-typeset _VERSION="2019-03-09"                           # YYYY-MM-DD
+typeset _VERSION="2019-03-16"                           # YYYY-MM-DD
 typeset _SUPPORTED_PLATFORMS="Linux"                    # uname -s match
 # ------------------------- CONFIGURATION ends here ---------------------------
 
@@ -141,9 +142,9 @@ else
 fi
 
 # check for checksum tools
-_OPENSSL_BIN="$(which openssl 2>>${HC_STDERR_LOG})"
+_OPENSSL_BIN="$(command -v openssl 2>>${HC_STDERR_LOG})"
 [[ -x ${_OPENSSL_BIN} && -n "${_OPENSSL_BIN}" ]] && _HAS_OPENSSL=1
-_CKSUM_BIN="$(which cksum 2>>${HC_STDERR_LOG})"
+_CKSUM_BIN="$(command -v cksum 2>>${HC_STDERR_LOG})"
 [[ -x ${_CKSUM_BIN} && -n "${_CKSUM_BIN}" ]] && _HAS_CKSUM=1
 # prefer openssl (for sha256)
 if (( _HAS_OPENSSL == 1 ))
diff --git a/sources/lib/platform/linux/check_linux_httpd_status.sh b/sources/lib/platform/linux/check_linux_httpd_status.sh
index 104dcec..9958465 100644
--- a/sources/lib/platform/linux/check_linux_httpd_status.sh
+++ b/sources/lib/platform/linux/check_linux_httpd_status.sh
@@ -29,6 +29,7 @@
 # @(#) 2018-11-18: add linux_has_systemd_service() [Patrick Van der Veken]
 # @(#) 2019-01-24: arguments fix [Patrick Van der Veken]
 # @(#) 2019-03-09: added support for --log-healthy [Patrick Van der Veken]
+# @(#) 2019-03-16: replace 'which' [Patrick Van der Veken]
 # -----------------------------------------------------------------------------
 # DO NOT CHANGE THIS FILE UNLESS YOU KNOW WHAT YOU ARE DOING!
 #******************************************************************************
@@ -39,7 +40,7 @@ function check_linux_httpd_status
 # ------------------------- CONFIGURATION starts here -------------------------
 typeset _HTTPD_INIT_SCRIPT="/etc/init.d/httpd"
 typeset _HTTPD_SYSTEMD_SERVICE="httpd.service"
-typeset _VERSION="2019-03-09"                           # YYYY-MM-DD
+typeset _VERSION="2019-03-16"                           # YYYY-MM-DD
 typeset _SUPPORTED_PLATFORMS="Linux"                    # uname -s match
 # ------------------------- CONFIGURATION ends here ---------------------------
 
@@ -139,7 +140,7 @@ then
 fi
 
 # ---- config state ----
-_HTTPD_BIN="$(which httpd 2>>${HC_STDERR_LOG})"
+_HTTPD_BIN="$(command -v httpd 2>>${HC_STDERR_LOG})"
 if [[ -x ${_HTTPD_BIN} && -n "${_HTTPD_BIN}" ]]
 then
     # validate main configuration
diff --git a/sources/lib/platform/linux/check_linux_mysqld_status.sh b/sources/lib/platform/linux/check_linux_mysqld_status.sh
index 25e28db..ced7b88 100644
--- a/sources/lib/platform/linux/check_linux_mysqld_status.sh
+++ b/sources/lib/platform/linux/check_linux_mysqld_status.sh
@@ -25,6 +25,7 @@
 # @(#) HISTORY:
 # @(#) 2019-02-10: initial version [Patrick Van der Veken]
 # @(#) 2019-03-09: text files [Patrick Van der Veken]
+# @(#) 2019-03-16: replace 'which' [Patrick Van der Veken]
 # -----------------------------------------------------------------------------
 # DO NOT CHANGE THIS FILE UNLESS YOU KNOW WHAT YOU ARE DOING!
 #******************************************************************************
@@ -38,7 +39,7 @@ typeset _MYSQLD_INIT_SCRIPT="/etc/init.d/mysqld"
 typeset _MYSQLD_SYSTEMD_SERVICE="mysqld.service"
 typeset _MARIADB_INIT_SCRIPT="/etc/init.d/mariadb"
 typeset _MARIADB_SYSTEMD_SERVICE="mariadb.service"
-typeset _VERSION="2019-03-09"                           # YYYY-MM-DD
+typeset _VERSION="2019-03-16"                           # YYYY-MM-DD
 typeset _SUPPORTED_PLATFORMS="Linux"                    # uname -s match
 # ------------------------- CONFIGURATION ends here ---------------------------
 
@@ -181,7 +182,7 @@ else
 fi
 
 # check mysql
-_MYSQL_BIN="$(which mysql 2>>${HC_STDERR_LOG})"
+_MYSQL_BIN="$(command -v mysql 2>>${HC_STDERR_LOG})"
 if [[ ! -x ${_MYSQL_BIN} || -z "${_MYSQL_BIN}" ]]
 then
     warn "MySQL/mariaDB is not installed here"
@@ -265,7 +266,7 @@ fi
 
 # ---- table states (ISAM)----
 # check mysqlcheck
-_MYSQLCHECK_BIN="$(which mysqlcheck 2>>${HC_STDERR_LOG})"
+_MYSQLCHECK_BIN="$(command -v mysqlcheck 2>>${HC_STDERR_LOG})"
 if [[ ! -x ${_MYSQLCHECK_BIN} || -z "${_MYSQLCHECK_BIN}" ]]
 then
     warn "could not find {mysqlcheck}, skipping table checks"
@@ -278,7 +279,7 @@ then
     if [[ -z "${_CFG_CHECK_DATABASES}" ]]
     then
         # check mysqlshow
-        _MYSQLSHOW_BIN="$(which mysqlshow 2>>${HC_STDERR_LOG})"
+        _MYSQLSHOW_BIN="$(command -v mysqlshow 2>>${HC_STDERR_LOG})"
         if [[ ! -x ${_MYSQLSHOW_BIN} || -z "${_MYSQLSHOW_BIN}" ]]
         then
             warn "could not find {mysqlshow}, skipping table checks"
@@ -347,7 +348,7 @@ fi
 
 # ---- statistics ----
 # check mysqladmin
-_MYSQLADMIN_BIN="$(which mysqladmin 2>>${HC_STDERR_LOG})"
+_MYSQLADMIN_BIN="$(command -v mysqladmin 2>>${HC_STDERR_LOG})"
 if [[ ! -x ${_MYSQLADMIN_BIN} || -z "${_MYSQLADMIN_BIN}" ]]
 then
     warn "could not find {mysqladmin}, skipping statistics gathering"
diff --git a/sources/lib/platform/linux/check_linux_named_status.sh b/sources/lib/platform/linux/check_linux_named_status.sh
index d9ece14..81b8b75 100644
--- a/sources/lib/platform/linux/check_linux_named_status.sh
+++ b/sources/lib/platform/linux/check_linux_named_status.sh
@@ -28,6 +28,7 @@
 # @(#) 2018-11-18: add linux_has_systemd_service() [Patrick Van der Veken]
 # @(#) 2019-01-24: arguments fix [Patrick Van der Veken]
 # @(#) 2019-03-09: added support for --log-healthy [Patrick Van der Veken]
+# @(#) 2019-03-16: replace 'which' [Patrick Van der Veken]
 # -----------------------------------------------------------------------------
 # DO NOT CHANGE THIS FILE UNLESS YOU KNOW WHAT YOU ARE DOING!
 #******************************************************************************
@@ -36,7 +37,7 @@
 function check_linux_named_status
 {
 # ------------------------- CONFIGURATION starts here -------------------------
-typeset _VERSION="2019-03-09"                           # YYYY-MM-DD
+typeset _VERSION="2019-03-16"                           # YYYY-MM-DD
 typeset _SUPPORTED_PLATFORMS="Linux"                    # uname -s match
 # ------------------------- CONFIGURATION ends here ---------------------------
 
@@ -150,7 +151,7 @@ then
 fi
 
 # ---- config state ----
-_NAMED_CHECKCONF_BIN="$(which named-checkconf 2>>${HC_STDERR_LOG})"
+_NAMED_CHECKCONF_BIN="$(command -v named-checkconf 2>>${HC_STDERR_LOG})"
 if [[ -x ${_NAMED_CHECKCONF_BIN} && -n "${_NAMED_CHECKCONF_BIN}" ]]
 then
     # validate main configuration and test load zones
diff --git a/sources/lib/platform/linux/check_linux_postfix_status.sh b/sources/lib/platform/linux/check_linux_postfix_status.sh
index d462770..bb05758 100644
--- a/sources/lib/platform/linux/check_linux_postfix_status.sh
+++ b/sources/lib/platform/linux/check_linux_postfix_status.sh
@@ -29,6 +29,7 @@
 # @(#) 2018-11-18: add linux_has_systemd_service() [Patrick Van der Veken]
 # @(#) 2019-01-24: arguments fix [Patrick Van der Veken]
 # @(#) 2019-03-09: added support for --log-healthy [Patrick Van der Veken]
+# @(#) 2019-03-16: replace 'which' [Patrick Van der Veken]
 # -----------------------------------------------------------------------------
 # DO NOT CHANGE THIS FILE UNLESS YOU KNOW WHAT YOU ARE DOING!
 #******************************************************************************
@@ -39,7 +40,7 @@ function check_linux_postfix_status
 # ------------------------- CONFIGURATION starts here -------------------------
 typeset _POSTFIX_INIT_SCRIPT="/etc/init.d/postfix"
 typeset _POSTFIX_SYSTEMD_SERVICE="postfix.service"
-typeset _VERSION="2019-03-09"                           # YYYY-MM-DD
+typeset _VERSION="2019-03-16"                           # YYYY-MM-DD
 typeset _SUPPORTED_PLATFORMS="Linux"                    # uname -s match
 # ------------------------- CONFIGURATION ends here ---------------------------
 
@@ -117,7 +118,7 @@ esac
 # 2) try the postfix way
 if (( _RC > 0 ))
 then
-    _POSTFIX_BIN="$(which postfix 2>>${HC_STDERR_LOG})"
+    _POSTFIX_BIN="$(command -v postfix 2>>${HC_STDERR_LOG})"
     if [[ -x ${_POSTFIX_BIN} && -n "${_POSTFIX_BIN}" ]]
     then
         if (( $(${_POSTFIX_BIN} status 2>>${HC_STDERR_LOG} | grep -c -i 'is running' 2>/dev/null) == 0 ))