diff --git a/scripts/zfs-tests.sh b/scripts/zfs-tests.sh
index 851ff8b74e52..d82c5923a990 100755
--- a/scripts/zfs-tests.sh
+++ b/scripts/zfs-tests.sh
@@ -53,7 +53,7 @@ TAGS=""
 ITERATIONS=1
 ZFS_DBGMSG="$STF_SUITE/callbacks/zfs_dbgmsg.ksh"
 ZFS_DMESG="$STF_SUITE/callbacks/zfs_dmesg.ksh"
-UNAME=$(uname -s)
+UNAME=$(uname)
 RERUN=""
 KMEMLEAK=""
 
diff --git a/scripts/zfs.sh b/scripts/zfs.sh
index 0561092a089f..edce2cbd4c64 100755
--- a/scripts/zfs.sh
+++ b/scripts/zfs.sh
@@ -260,7 +260,7 @@ if [ "$(id -u)" != 0 ]; then
 	exit 1
 fi
 
-UNAME=$(uname -s)
+UNAME=$(uname)
 
 if [ "$UNLOAD" = "yes" ]; then
 	kill_zed
diff --git a/tests/zfs-tests/include/default.cfg.in b/tests/zfs-tests/include/default.cfg.in
index cf382cfe994c..a9a17de34ae7 100644
--- a/tests/zfs-tests/include/default.cfg.in
+++ b/tests/zfs-tests/include/default.cfg.in
@@ -170,8 +170,8 @@ if [ "@UBSAN_ENABLED@" = "yes" ]; then
 fi
 
 
-case $(uname -o) in
-GNU/Linux)
+case $(uname) in
+Linux)
 	unpack_opts="--sparse -xf"
 	pack_opts="--sparse -cf"
 	verbose=" -v"
@@ -209,7 +209,7 @@ FreeBSD)
 	NEWFS_DEFAULT_FS="ufs"
 	SLICE_PREFIX="p"
 	;;
-illumos)
+*)
 	export AUTO_SNAP=$(svcs -a | \
 	    awk '/auto-snapshot/ && /online/ { print $3 }')
 	# finally, if we're running in a local zone
diff --git a/tests/zfs-tests/include/libtest.shlib b/tests/zfs-tests/include/libtest.shlib
index 3c0cd04c5e0f..79930bb293e1 100644
--- a/tests/zfs-tests/include/libtest.shlib
+++ b/tests/zfs-tests/include/libtest.shlib
@@ -88,11 +88,7 @@ function linux_version
 
 function is_linux
 {
-	if [[ $(uname -o) == "GNU/Linux" ]]; then
-		return 0
-	else
-		return 1
-	fi
+	[ $(uname) = "Linux" ]
 }
 
 # Determine if this is an illumos test system
@@ -100,11 +96,7 @@ function is_linux
 # Return 0 if platform illumos, 1 if otherwise
 function is_illumos
 {
-	if [[ $(uname -o) == "illumos" ]]; then
-		return 0
-	else
-		return 1
-	fi
+	[ $(uname) = "illumos" ]
 }
 
 # Determine if this is a FreeBSD test system
@@ -113,11 +105,7 @@ function is_illumos
 
 function is_freebsd
 {
-	if [[ $(uname -o) == "FreeBSD" ]]; then
-		return 0
-	else
-		return 1
-	fi
+	[ $(uname) = "FreeBSD" ]
 }
 
 # Determine if this is a DilOS test system
@@ -128,11 +116,7 @@ function is_dilos
 {
 	typeset ID=""
 	[[ -f /etc/os-release ]] && . /etc/os-release
-	if [[ $ID == "dilos" ]]; then
-		return 0
-	else
-		return 1
-	fi
+	[ "$ID" = "dilos" ]
 }
 
 # Determine if this is a 32-bit system
@@ -141,11 +125,7 @@ function is_dilos
 
 function is_32bit
 {
-	if [[ $(getconf LONG_BIT) == "32" ]]; then
-		return 0
-	else
-		return 1
-	fi
+	[ $(getconf LONG_BIT) = "32" ]
 }
 
 # Determine if kmemleak is enabled
@@ -154,11 +134,7 @@ function is_32bit
 
 function is_kmemleak
 {
-	if is_linux && [[ -e /sys/kernel/debug/kmemleak ]]; then
-		return 0
-	else
-		return 1
-	fi
+	is_linux && [ -e /sys/kernel/debug/kmemleak ]
 }
 
 # Determine whether a dataset is mounted
@@ -1487,14 +1463,7 @@ function is_shared_smb
 #
 function not_shared
 {
-	typeset fs=$1
-
-	is_shared $fs
-	if (($? == 0)); then
-		return 1
-	fi
-
-	return 0
+	! is_shared $1
 }
 
 #
@@ -1504,14 +1473,7 @@ function not_shared
 #
 function not_shared_smb
 {
-	typeset fs=$1
-
-	is_shared_smb $fs
-	if (($? == 0)); then
-		return 1
-	fi
-
-	return 0
+	! is_shared_smb $1
 }
 
 #
@@ -1521,12 +1483,9 @@ function unshare_fs #fs
 {
 	typeset fs=$1
 
-	is_shared $fs || is_shared_smb $fs
-	if (($? == 0)); then
+	if is_shared $fs || is_shared_smb $fs; then
 		zfs unshare $fs || log_fail "zfs unshare $fs failed"
 	fi
-
-	return 0
 }
 
 #
@@ -1536,14 +1495,10 @@ function share_nfs #fs
 {
 	typeset fs=$1
 
-	if is_linux; then
-		is_shared $fs
-		if (($? != 0)); then
+	if ! is_shared $fs; then
+		if is_linux; then
 			log_must share "*:$fs"
-		fi
-	else
-		is_shared $fs
-		if (($? != 0)); then
+		else
 			log_must share -F nfs $fs
 		fi
 	fi
@@ -1558,14 +1513,10 @@ function unshare_nfs #fs
 {
 	typeset fs=$1
 
-	if is_linux; then
-		is_shared $fs
-		if (($? == 0)); then
+	if is_shared $fs; then
+		if is_linux; then
 			log_must unshare -u "*:$fs"
-		fi
-	else
-		is_shared $fs
-		if (($? == 0)); then
+		else
 			log_must unshare -F nfs $fs
 		fi
 	fi
@@ -1693,10 +1644,7 @@ function is_global_zone
 		return 0
 	else
 		typeset cur_zone=$(zonename 2>/dev/null)
-		if [[ $cur_zone != "global" ]]; then
-			return 1
-		fi
-		return 0
+		[ $cur_zone = "global" ]
 	fi
 }