diff --git a/test/sharness/t0021-config.sh b/test/sharness/t0021-config.sh
index 7d8e97dd5..fdfe94b96 100755
--- a/test/sharness/t0021-config.sh
+++ b/test/sharness/t0021-config.sh
@@ -74,8 +74,8 @@ test_config_cmd() {
 
   test_expect_success "setup for config replace test" '
     cp "$IPFS_PATH/config" newconfig.json &&
-	</dev/null sed -e /PrivKey/d -e s/10GB/11GB/ -i  newconfig.json &&
-	</dev/null sed -e '"'"'/PeerID/ { s/,$// } '"'"' -i newconfig.json
+	</dev/null sed -e /PrivKey/d -e s/10GB/11GB/ -i"~"  newconfig.json &&
+	</dev/null sed -e '"'"'/PeerID/ { s/,$// } '"'"' -i"~" newconfig.json
   '
 
   test_expect_success "run 'ipfs config replace'" '
@@ -84,7 +84,7 @@ test_config_cmd() {
 
   test_expect_success "check resulting config after 'ipfs config replace'" '
 	sed -e /PrivKey/d "$IPFS_PATH/config" > replconfig.json &&
-	sed -e '"'"'/PeerID/ { s/,$// } '"'"' -i replconfig.json &&
+	sed -e '"'"'/PeerID/ { s/,$// } '"'"' -i"~" replconfig.json &&
 	test_cmp replconfig.json newconfig.json
   '
 
@@ -109,7 +109,7 @@ test_config_cmd() {
   '
 
   test_expect_success "lower cased PrivKey" '
-       sed -i -e '\''s/PrivKey/privkey/'\'' "$IPFS_PATH/config" &&
+       sed -i"~" -e '\''s/PrivKey/privkey/'\'' "$IPFS_PATH/config" &&
        test_expect_code 1 ipfs config Identity.privkey 2> ident_out
   '