diff --git a/bin/tests/system/dnssec/ns2/sign.sh b/bin/tests/system/dnssec/ns2/sign.sh
index dfe35fea9d..1bfaa37a04 100644
--- a/bin/tests/system/dnssec/ns2/sign.sh
+++ b/bin/tests/system/dnssec/ns2/sign.sh
@@ -196,8 +196,10 @@ cat > "$zonefile" << EOF
 ns2	10	A	10.53.0.2
 ns3	10	A	10.53.0.3
 EOF
-for i in $(seq 300); do
+i=1
+while [ $i -le 300 ]; do
     echo "host$i 10 IN NS ns.elsewhere"
+    i=$((i+1))
 done >> "$zonefile"
 key1=$("$KEYGEN" -q -a "$DEFAULT_ALGORITHM" -b "$DEFAULT_BITS" -n zone -f KSK "$zone")
 key2=$("$KEYGEN" -q -a "$DEFAULT_ALGORITHM" -b "$DEFAULT_BITS" -n zone "$zone")
diff --git a/bin/tests/system/kasp/tests.sh b/bin/tests/system/kasp/tests.sh
index 378df45fa3..e875e406c9 100644
--- a/bin/tests/system/kasp/tests.sh
+++ b/bin/tests/system/kasp/tests.sh
@@ -5661,10 +5661,10 @@ dnssec_verify
 n=$((n+1))
 echo_i "check that of zone ${ZONE} migration to dnssec-policy uses the same keys ($n)"
 ret=0
-[ $_migrate_ext8_ksk == $_migrate_int8_ksk ] || log_error "mismatch ksk tag"
-[ $_migrate_ext8_zsk == $_migrate_int8_zsk ] || log_error "mismatch zsk tag"
-[ $_migrate_ext8_ksk == $(key_get KEY1 ID) ] || log_error "mismatch ksk tag"
-[ $_migrate_ext8_zsk == $(key_get KEY2 ID) ] || log_error "mismatch zsk tag"
+[ $_migrate_ext8_ksk = $_migrate_int8_ksk ] || log_error "mismatch ksk tag"
+[ $_migrate_ext8_zsk = $_migrate_int8_zsk ] || log_error "mismatch zsk tag"
+[ $_migrate_ext8_ksk = $(key_get KEY1 ID) ] || log_error "mismatch ksk tag"
+[ $_migrate_ext8_zsk = $(key_get KEY2 ID) ] || log_error "mismatch zsk tag"
 status=$((status+ret))
 
 echo_i "exit status: $status"
diff --git a/bin/tests/system/rpz/tests.sh b/bin/tests/system/rpz/tests.sh
index d73ccb939e..c728c45d5c 100644
--- a/bin/tests/system/rpz/tests.sh
+++ b/bin/tests/system/rpz/tests.sh
@@ -208,7 +208,7 @@ restart () {
 	fi
     fi
     rm -f ns$1/*.jnl
-    if [ "$2" == "rebuild-bl-rpz" ]; then
+    if [ "$2" = "rebuild-bl-rpz" ]; then
         if test -f ns$1/base.db; then
 	    for NM in ns$1/bl*.db; do
 	        cp -f ns$1/base.db $NM