diff --git a/iucvterm/doc/ts-shell/iucvconn_on_login b/iucvterm/doc/ts-shell/iucvconn_on_login
index 860c4ccf..92010dfa 100755
--- a/iucvterm/doc/ts-shell/iucvconn_on_login
+++ b/iucvterm/doc/ts-shell/iucvconn_on_login
@@ -15,7 +15,7 @@
 prog_name=`basename $0`
 guest_name=${USER:-`whoami 2>/dev/null`}
 terminal=lnxhvc0
-iucvconn=`which iucvconn 2>/dev/null`
+iucvconn=`command -v iucvconn 2>/dev/null`
 
 __error() {
 	printf "$prog_name: $@\n" >&2
diff --git a/netboot/mk-pxelinux-ramfs b/netboot/mk-pxelinux-ramfs
index 64ebde1c..07f8b075 100755
--- a/netboot/mk-pxelinux-ramfs
+++ b/netboot/mk-pxelinux-ramfs
@@ -127,7 +127,7 @@ echo "$cmd: Copying kexec"
 # Install both binary and required shared libraries
 OLDPATH=$PATH
 PATH=$OLDPATH:/sbin:/usr/sbin
-kexec_bin=$(which kexec)
+kexec_bin=$(command -v kexec)
 kexec_sos=$(sharedobjs $kexec_bin)
 PATH=$OLDPATH
 
diff --git a/ziomon/ziomon b/ziomon/ziomon
index fd6248a3..d1545ccb 100755
--- a/ziomon/ziomon
+++ b/ziomon/ziomon
@@ -667,8 +667,7 @@ function check_free_space_mileage() {
 
 
 function check_blktrace() {
-   which blktrace >/dev/null 2>&1;
-   if [ $? -ne 0 ]; then
+   if ! command -v blktrace >/dev/null 2>&1; then
       echo "$WRP_TOOLNAME: Could not find blktrace. Please make sure that the blktrace package is installed and matches the level in the documentation.";
       exit 1;
    fi