diff --git a/tests/zfs-tests/tests/functional/cli_root/zdb/zdb_objset_id.ksh b/tests/zfs-tests/tests/functional/cli_root/zdb/zdb_objset_id.ksh
index c3021d1759..fdda9ba226 100755
--- a/tests/zfs-tests/tests/functional/cli_root/zdb/zdb_objset_id.ksh
+++ b/tests/zfs-tests/tests/functional/cli_root/zdb/zdb_objset_id.ksh
@@ -67,34 +67,32 @@ obj=${array[0]}
 log_note "file $init_data has object number $obj"
 sync_pool $TESTPOOL
 
-output=$(zdb -d $TESTPOOL/$TESTFS)
-objset_id=$(echo $output | cut -d, -f2 | cut -d' ' -f2)
+IFS=", " read -r _ _ _ _ objset_id _ < <(zdb -d $TESTPOOL/$TESTFS)
 objset_hex=$(printf "0x%X" $objset_id)
 log_note "objset $TESTPOOL/$TESTFS has objset ID $objset_id ($objset_hex)"
 
 for id in "$objset_id" "$objset_hex"
 do
 	log_note "zdb -dddddd $TESTPOOL/$id $obj"
-		output=$(zdb -dddddd $TESTPOOL/$id $obj)
-		echo $output | grep -q "$TESTPOOL/$TESTFS" ||
-			log_fail "zdb -dddddd $TESTPOOL/$id $obj failed ($TESTPOOL/$TESTFS not in zdb output)"
-		echo $output | grep -q "file1" ||
-			log_fail "zdb -dddddd $TESTPOOL/$id $obj failed (file1 not in zdb output)"
+	output=$(zdb -dddddd $TESTPOOL/$id $obj)
+	echo $output | grep -q "$TESTPOOL/$TESTFS" ||
+		log_fail "zdb -dddddd $TESTPOOL/$id $obj failed ($TESTPOOL/$TESTFS not in zdb output)"
+	echo $output | grep -q "file1" ||
+		log_fail "zdb -dddddd $TESTPOOL/$id $obj failed (file1 not in zdb output)"
 
 	obj=$(printf "0x%X" $obj)
 	log_note "zdb -NNNNNN $TESTPOOL/$id $obj"
-        output=$(zdb -NNNNNN $TESTPOOL/$id $obj)
-        echo $output | grep -q "$TESTPOOL/$TESTFS" ||
-        	log_fail "zdb -NNNNNN $TESTPOOL/$id $obj failed ($TESTPOOL/$TESTFS not in zdb output)"
-        echo $output | grep -q "file1" ||
-        	log_fail "zdb -NNNNNN $TESTPOOL/$id $obj failed (file1 not in zdb output)"
+	output=$(zdb -NNNNNN $TESTPOOL/$id $obj)
+	echo $output | grep -q "$TESTPOOL/$TESTFS" ||
+		log_fail "zdb -NNNNNN $TESTPOOL/$id $obj failed ($TESTPOOL/$TESTFS not in zdb output)"
+	echo $output | grep -q "file1" ||
+		log_fail "zdb -NNNNNN $TESTPOOL/$id $obj failed (file1 not in zdb output)"
 done
 
 if is_linux; then
-	output=$(ls -1 /proc/spl/kstat/zfs/$TESTPOOL |grep objset- |tail -1)
+	output=$(ls -1 /proc/spl/kstat/zfs/$TESTPOOL | grep objset- | tail -1)
 	objset_hex=${output#*-}
-	name_from_proc=$(cat /proc/spl/kstat/zfs/$TESTPOOL/$output |
-	    grep dataset_name | cut -d' ' -f3)
+	name_from_proc=$(grep dataset_name /proc/spl/kstat/zfs/$TESTPOOL/$output | cut -d' ' -f3)
 	log_note "checking zdb output for $name_from_proc"
 	log_must eval "zdb -dddddd $TESTPOOL/$objset_hex | grep -q \"$name_from_proc\""
 fi
diff --git a/tests/zfs-tests/tests/functional/cli_root/zfs_receive/zfs_receive_005_neg.ksh b/tests/zfs-tests/tests/functional/cli_root/zfs_receive/zfs_receive_005_neg.ksh
index d8c71f2c28..6a708a45e1 100755
--- a/tests/zfs-tests/tests/functional/cli_root/zfs_receive/zfs_receive_005_neg.ksh
+++ b/tests/zfs-tests/tests/functional/cli_root/zfs_receive/zfs_receive_005_neg.ksh
@@ -80,8 +80,8 @@ log_must zfs snapshot $init_snap
 log_must eval "zfs send $init_snap > $full_bkup"
 
 log_note "'zfs receive' fails with invalid send streams."
-log_mustnot eval "cat </dev/zero | zfs receive $rst_init_snap"
-log_mustnot eval "cat </dev/zero | zfs receive -d $rst_root"
+log_mustnot eval "cat /dev/zero | zfs receive $rst_init_snap"
+log_mustnot eval "cat /dev/zero | zfs receive -d $rst_root"
 
 log_must eval "zfs receive $rst_init_snap < $full_bkup"
 
diff --git a/tests/zfs-tests/tests/functional/history/history_007_pos.ksh b/tests/zfs-tests/tests/functional/history/history_007_pos.ksh
index c0ce0aae74..3d785183d0 100755
--- a/tests/zfs-tests/tests/functional/history/history_007_pos.ksh
+++ b/tests/zfs-tests/tests/functional/history/history_007_pos.ksh
@@ -70,7 +70,7 @@ for arch in "i386" "sparc"; do
 	orig_cmds_f=$import_dir/${arch}.orig_history.txt
 	# remove blank line
 	orig_cmds_f1=$import_dir/${arch}.orig_history_1.txt
-	cat $orig_cmds_f | grep -v "^$" > $orig_cmds_f1
+	grep -v "^$" $orig_cmds_f > $orig_cmds_f1
 
 	log_must cp $tst_dir/${arch}.migratedpool.DAT.Z $import_dir
 	log_must uncompress -f $import_dir/${arch}.migratedpool.DAT.Z
diff --git a/tests/zfs-tests/tests/functional/mmp/mmp_write_distribution.ksh b/tests/zfs-tests/tests/functional/mmp/mmp_write_distribution.ksh
index b6bdc68116..1ac254aa1d 100755
--- a/tests/zfs-tests/tests/functional/mmp/mmp_write_distribution.ksh
+++ b/tests/zfs-tests/tests/functional/mmp/mmp_write_distribution.ksh
@@ -37,7 +37,7 @@ verify_runnable "both"
 function cleanup
 {
 	log_must zpool destroy $MMP_POOL
-	log_must rm $MMP_DIR/file.{0,1,2,3,4,5,6,7}
+	log_must rm $MMP_DIR/file.{0..7}
 	log_must rm $MMP_HISTORY_TMP
 	log_must rmdir $MMP_DIR
 	log_must mmp_clear_hostid
@@ -51,8 +51,8 @@ MMP_HISTORY=/proc/spl/kstat/zfs/$MMP_POOL/multihost
 
 # Step 1
 log_must mkdir -p $MMP_DIR
-log_must truncate -s 128M $MMP_DIR/file.{0,1,2,3,4,5,6,7}
-log_must zpool create -f $MMP_POOL mirror $MMP_DIR/file.{0,1} mirror $MMP_DIR/file.{2,3,4,5,6,7}
+log_must truncate -s 128M $MMP_DIR/file.{0..7}
+log_must zpool create -f $MMP_POOL mirror $MMP_DIR/file.{0..1} mirror $MMP_DIR/file.{2..7}
 
 # Step 2
 log_must mmp_set_hostid $HOSTID1
@@ -69,8 +69,8 @@ typeset -i min_writes=999
 typeset -i max_writes=0
 typeset -i write_count
 # copy to get as close to a consistent view as possible
-cat $MMP_HISTORY > $MMP_HISTORY_TMP
-for x in $(seq 0 7); do
+cp $MMP_HISTORY $MMP_HISTORY_TMP
+for x in {0..7}; do
 	write_count=$(grep -c file.${x} $MMP_HISTORY_TMP)
 	if [ $write_count -lt $min_writes ]; then
 		min_writes=$write_count
diff --git a/tests/zfs-tests/tests/functional/pam/utilities.kshlib b/tests/zfs-tests/tests/functional/pam/utilities.kshlib
index d328034300..6e9f900913 100644
--- a/tests/zfs-tests/tests/functional/pam/utilities.kshlib
+++ b/tests/zfs-tests/tests/functional/pam/utilities.kshlib
@@ -28,7 +28,7 @@ pamservice="pam_zfs_key_test"
 pamconfig="/etc/pam.d/${pamservice}"
 
 function keystatus {
-    log_must [ "$(zfs list -Ho keystatus "$TESTPOOL/pam/${username}")" == "$1" ]
+    log_must [ "$(zfs list -Ho keystatus "$TESTPOOL/pam/${username}")" = "$1" ]
 }
 
 function genconfig {
@@ -42,6 +42,6 @@ function rmconfig {
 }
 
 function references {
-    log_must [ "$(cat "${runstatedir}/$(id -u ${username})")" == "$1" ]
+    log_must [ "$(<"${runstatedir}/$(id -u ${username})")" = "$1" ]
 }
 
diff --git a/tests/zfs-tests/tests/functional/procfs/procfs_list_basic.ksh b/tests/zfs-tests/tests/functional/procfs/procfs_list_basic.ksh
index 5f6727ea44..18caea3c32 100755
--- a/tests/zfs-tests/tests/functional/procfs/procfs_list_basic.ksh
+++ b/tests/zfs-tests/tests/functional/procfs/procfs_list_basic.ksh
@@ -85,7 +85,7 @@ done
 
 # Clear out old messages and check that they really are gone
 echo 0 >$ZFS_DBGMSG || log_fail "failed to write to $ZFS_DBGMSG"
-cat $ZFS_DBGMSG | count_snap_cmds 0
+count_snap_cmds 0 < $ZFS_DBGMSG
 #
 # Even though we don't expect any messages in the file, reading should still
 # succeed.
diff --git a/tests/zfs-tests/tests/functional/procfs/procfs_list_concurrent_readers.ksh b/tests/zfs-tests/tests/functional/procfs/procfs_list_concurrent_readers.ksh
index a24452ed58..fcdd54da35 100755
--- a/tests/zfs-tests/tests/functional/procfs/procfs_list_concurrent_readers.ksh
+++ b/tests/zfs-tests/tests/functional/procfs/procfs_list_concurrent_readers.ksh
@@ -41,8 +41,7 @@
 
 function cleanup
 {
-	[[ -z $msgs1 ]] || log_must rm $msgs1
-	[[ -z $msgs2 ]] || log_must rm $msgs2
+	log_must rm -f $msgs1 $msgs2
 	datasetexists $FS && destroy_dataset $FS -r
 }
 
@@ -69,7 +68,7 @@ msgs2=$(mktemp) || log_fail
 # Start reading file, pause and read it from another process, and then finish
 # reading.
 #
-{ dd bs=512 count=4; cat $ZFS_DBGMSG >$msgs1; cat; } <$ZFS_DBGMSG >$msgs2
+{ dd bs=512 count=4; cp $ZFS_DBGMSG $msgs1; cat; } <$ZFS_DBGMSG >$msgs2
 
 #
 # Truncate the result of the read that completed second in case it picked up an
diff --git a/tests/zfs-tests/tests/functional/redacted_send/redacted.kshlib b/tests/zfs-tests/tests/functional/redacted_send/redacted.kshlib
index 6ad2e47018..a3810d55f9 100644
--- a/tests/zfs-tests/tests/functional/redacted_send/redacted.kshlib
+++ b/tests/zfs-tests/tests/functional/redacted_send/redacted.kshlib
@@ -231,7 +231,7 @@ function compare_files
 	[[ -f $file2 ]] || log_fail "File $file2 does not exist."
 
 	log_must eval "get_diff $file1 $file2 >$tmpfile"
-	typeset range="$(cat $tmpfile)"
+	typeset range="$(<$tmpfile)"
 	log_must unmount_redacted $recvfs
 	[[ "$expected" = "$range" ]] || log_fail "Unexpected range: $range"
 }
diff --git a/tests/zfs-tests/tests/functional/redacted_send/redacted_embedded.ksh b/tests/zfs-tests/tests/functional/redacted_send/redacted_embedded.ksh
index 1c5b503a9b..35faf038ad 100755
--- a/tests/zfs-tests/tests/functional/redacted_send/redacted_embedded.ksh
+++ b/tests/zfs-tests/tests/functional/redacted_send/redacted_embedded.ksh
@@ -60,13 +60,10 @@ for recsize in 512 1024 2048 4096 8192 16384; do
 	log_must eval "zdb -ddddd $sendfs $send_obj >$tmpdir/send.zdb"
 	log_must eval "zdb -ddddd $recvfs $recv_obj >$tmpdir/recv.zdb"
 
-	grep -q "EMBEDDED" $tmpdir/send.zdb || \
-	    log_fail "Obj $send_obj not embedded in $sendfs"
-	grep -q "EMBEDDED" $tmpdir/recv.zdb || \
-	    log_fail "Obj $recv_obj not embedded in $recvfs"
+	log_must grep -q "EMBEDDED" $tmpdir/send.zdb
+	log_must grep -q "EMBEDDED" $tmpdir/recv.zdb
 
-	cat $stream | zstream dump -v | log_must grep -q \
-	    "WRITE_EMBEDDED object = $send_obj offset = 0"
+	log_must eval "zstream dump -v $stream | grep -q \"WRITE_EMBEDDED object = $send_obj offset = 0\""
 done
 
 log_must zfs destroy -R $recvfs
@@ -91,13 +88,10 @@ for recsize in 1024 4096 16384; do
 	log_must eval "zdb -ddddd $sendfs $send_obj >$tmpdir/send.zdb"
 	log_must eval "zdb -ddddd $recvfs $recv_obj >$tmpdir/recv.zdb"
 
-	grep -q "EMBEDDED" $tmpdir/send.zdb || \
-	    log_fail "Obj $send_obj not embedded in $sendfs"
-	grep -q "EMBEDDED" $tmpdir/recv.zdb || \
-	    log_fail "Obj $recv_obj not embedded in $recvfs"
+	log_must grep -q "EMBEDDED" $tmpdir/send.zdb
+	log_must grep -q "EMBEDDED" $tmpdir/recv.zdb
 
-	cat $stream | zstream dump -v | log_must grep -q \
-	    "WRITE_EMBEDDED object = $send_obj offset = 0"
+	log_must eval "zstream dump -v $stream | log_must grep -q \"WRITE_EMBEDDED object = $send_obj offset = 0\""
 done
 
 log_pass "Embedded blocks and redacted send work correctly together."
diff --git a/tests/zfs-tests/tests/functional/redacted_send/redacted_resume.ksh b/tests/zfs-tests/tests/functional/redacted_send/redacted_resume.ksh
index 8118ea59ec..31f7b0ada8 100755
--- a/tests/zfs-tests/tests/functional/redacted_send/redacted_resume.ksh
+++ b/tests/zfs-tests/tests/functional/redacted_send/redacted_resume.ksh
@@ -53,7 +53,7 @@ log_must mount_redacted -f $recvfs
 log_must set_tunable32 ALLOW_REDACTED_DATASET_MOUNT 1
 log_must diff $send_mnt/f1 $recv_mnt/f1
 log_must eval "get_diff $send_mnt/f2 $recv_mnt/f2 >$tmpdir/get_diff.out"
-typeset range=$(cat $tmpdir/get_diff.out)
+typeset range=$(<$tmpdir/get_diff.out)
 [[ "$RANGE9" = "$range" ]] || log_fail "Unexpected range: $range"
 
 log_must dd if=/dev/urandom of=$send_mnt/f3 bs=1024k count=3
@@ -70,7 +70,7 @@ resume_test "zfs send --redact book2 -i $sendfs#book1 $sendfs@snap2" \
 log_must diff $send_mnt/f1 $recv_mnt/f1
 log_must diff $send_mnt/f2 $recv_mnt/f2
 log_must eval "get_diff $send_mnt/f3 $recv_mnt/f3 >$tmpdir/get_diff.out"
-range=$(cat $tmpdir/get_diff.out)
+range=$(<$tmpdir/get_diff.out)
 [[ "$RANGE10" = "$range" ]] || log_fail "Unexpected range: $range"
 
 # Test recv -A works properly and verify saved sends are not allowed
diff --git a/tests/zfs-tests/tests/functional/replacement/resilver_restart_001.ksh b/tests/zfs-tests/tests/functional/replacement/resilver_restart_001.ksh
index 937693a67c..b498ba4af7 100755
--- a/tests/zfs-tests/tests/functional/replacement/resilver_restart_001.ksh
+++ b/tests/zfs-tests/tests/functional/replacement/resilver_restart_001.ksh
@@ -162,7 +162,7 @@ do
 
 	# inject read io errors on vdev and verify resilver does not restart
 	log_must zinject -a -d ${VDEV_FILES[2]} -e io -T read -f 0.25 $TESTPOOL1
-	log_must eval "cat ${DATAPATHS[1]} > /dev/null"
+	log_must cp ${DATAPATHS[1]} /dev/null
 	log_must zinject -c all
 
 	# there should still be 2 resilver starts w/o defer, 1 with defer
diff --git a/tests/zfs-tests/tests/functional/rsend/rsend.kshlib b/tests/zfs-tests/tests/functional/rsend/rsend.kshlib
index 085b58954c..fdda1f5e92 100644
--- a/tests/zfs-tests/tests/functional/rsend/rsend.kshlib
+++ b/tests/zfs-tests/tests/functional/rsend/rsend.kshlib
@@ -625,7 +625,7 @@ function resume_test
 		log_mustnot eval "zfs recv -suv $recvfs </$streamfs/$stream_num"
 		stream_num=$((stream_num+1))
 
-		token=$(zfs get -Hp -o value receive_resume_token $recvfs)
+		token=$(get_prop receive_resume_token $recvfs)
 
 		# Do a dry-run
 		[ $dryrun -ne 0 ] && \
@@ -709,7 +709,7 @@ function stream_has_features
 	shift
 
 	[[ -f $file ]] || log_fail "Couldn't find file: $file"
-	typeset flags=$(cat $file | zstream dump | \
+	typeset flags=$(zstream dump $file | \
 	    awk '/features =/ {features = $3} END {print features}')
 	typeset -A feature
 	feature[dedup]="1"
@@ -759,7 +759,7 @@ function verify_stream_size
 	[[ -f $stream ]] || log_fail "No such file: $stream"
 	datasetexists $ds || log_fail "No such dataset: $ds"
 
-	typeset stream_size=$(cat $stream | zstream dump | sed -n \
+	typeset stream_size=$(zstream dump $stream | sed -n \
 	    's/	Total payload size = \(.*\) (0x.*)/\1/p')
 
 	typeset inc_size=0
@@ -777,8 +777,7 @@ function verify_stream_size
 	fi
 	ds_size=$((ds_size - inc_size))
 
-	within_percent $stream_size $ds_size $percent || log_fail \
-	    "$stream_size $ds_size differed by too much"
+	log_must within_percent $stream_size $ds_size $percent
 }
 
 # Cleanup function for tests involving resumable send
diff --git a/tests/zfs-tests/tests/functional/rsend/send-c_zstreamdump.ksh b/tests/zfs-tests/tests/functional/rsend/send-c_zstreamdump.ksh
index 5b9939c6a6..82d15c68ec 100755
--- a/tests/zfs-tests/tests/functional/rsend/send-c_zstreamdump.ksh
+++ b/tests/zfs-tests/tests/functional/rsend/send-c_zstreamdump.ksh
@@ -49,7 +49,7 @@ log_must zfs snapshot $sendfs@full
 
 log_must eval "zfs send -c $sendfs@full >$BACKDIR/full"
 log_must stream_has_features $BACKDIR/full lz4 compressed
-cat $BACKDIR/full | zstream dump -v > $BACKDIR/dump.out
+zstream dump -v $BACKDIR/full > $BACKDIR/dump.out
 
 lsize=$(awk '/^WRITE [^0]/ {lsize += $24} END {printf("%d", lsize)}' \
     $BACKDIR/dump.out)
@@ -63,8 +63,8 @@ csize_prop=$(get_prop used $sendfs)
 within_percent $csize $csize_prop 90 || log_fail \
     "$csize and $csize_prop differed by too much"
 
-x=$(get_resume_token "zfs send -c $sendfs@full" $streamfs $recvfs)
-resume_token=$(cat /$streamfs/resume_token)
+get_resume_token "zfs send -c $sendfs@full" $streamfs $recvfs
+resume_token=$(</$streamfs/resume_token)
 to_name_fs=$sendfs
 log_must eval "zstream token $resume_token | grep $to_name_fs"
 
diff --git a/tests/zfs-tests/tests/functional/rsend/send-cpL_varied_recsize.ksh b/tests/zfs-tests/tests/functional/rsend/send-cpL_varied_recsize.ksh
index 25ad8e0820..cf390c26f9 100755
--- a/tests/zfs-tests/tests/functional/rsend/send-cpL_varied_recsize.ksh
+++ b/tests/zfs-tests/tests/functional/rsend/send-cpL_varied_recsize.ksh
@@ -134,7 +134,7 @@ function check
 	[[ -f $stream ]] && log_must rm $stream
 	log_must eval "zfs send $flags $send_snap >$stream"
 	$verify eval "zfs recv $recv_ds <$stream"
-	typeset stream_size=$(cat $stream | zstream dump | sed -n \
+	typeset stream_size=$(zstream dump $stream | sed -n \
 	    's/	Total write size = \(.*\) (0x.*)/\1/p')
 
 	#
diff --git a/tests/zfs-tests/tests/functional/xattr/cleanup.ksh b/tests/zfs-tests/tests/functional/xattr/cleanup.ksh
index b3629629c7..ab0fbf8124 100755
--- a/tests/zfs-tests/tests/functional/xattr/cleanup.ksh
+++ b/tests/zfs-tests/tests/functional/xattr/cleanup.ksh
@@ -30,7 +30,7 @@
 . $STF_SUITE/include/libtest.shlib
 . $STF_SUITE/tests/functional/xattr/xattr_common.kshlib
 
-USES_NIS=$(cat $TEST_BASE_DIR/zfs-xattr-test-nis.txt)
+USES_NIS=$(<$TEST_BASE_DIR/zfs-xattr-test-nis.txt)
 rm $TEST_BASE_DIR/zfs-xattr-test-nis.txt
 
 if [ "${USES_NIS}" == "true" ]
diff --git a/tests/zfs-tests/tests/functional/xattr/xattr_common.kshlib b/tests/zfs-tests/tests/functional/xattr/xattr_common.kshlib
index bc06f47168..5ff2b48902 100644
--- a/tests/zfs-tests/tests/functional/xattr/xattr_common.kshlib
+++ b/tests/zfs-tests/tests/functional/xattr/xattr_common.kshlib
@@ -97,10 +97,10 @@ function delete_xattr { # filename xattr_name
         if is_illumos; then
 	        log_must runat $FILE rm $XATTR_NAME
 	        log_mustnot eval "runat $FILE ls $XATTR_NAME > /dev/null 2>&1"
-	else
-		log_must rm_xattr $XATTR_NAME $FILE
-		log_mustnot get_xattr $XATTR_NAME $FILE
-	fi
+        else
+            log_must rm_xattr $XATTR_NAME $FILE
+            log_mustnot get_xattr $XATTR_NAME $FILE
+        fi
 }
 
 # not sure about this : really this should be testing write/append
@@ -126,12 +126,6 @@ function verify_write_xattr { # filename xattr_name
 function create_expected_output { # expected_output_file  contents_of_the_output
 	typeset FILE=$1
 	shift
-	if [[ -f $FILE ]]; then
-		log_must rm $FILE
-	fi
-
-	for line in $@
-	do
-		log_must eval "echo $line >> $FILE"
-	done
+	log_must rm -f $FILE
+	log_must eval "printf '%s\n' $* >> $FILE"
 }