diff --git a/cmd/zfs/zfs_main.c b/cmd/zfs/zfs_main.c
index c85154479c..d75f089acd 100644
--- a/cmd/zfs/zfs_main.c
+++ b/cmd/zfs/zfs_main.c
@@ -2239,7 +2239,7 @@ zfs_do_upgrade(int argc, char **argv)
 	boolean_t showversions = B_FALSE;
 	int ret = 0;
 	upgrade_cbdata_t cb = { 0 };
-	signed char c;
+	int c;
 	int flags = ZFS_ITER_ARGS_CAN_BE_PATHS;
 
 	/* check options */
@@ -3933,7 +3933,7 @@ static int
 zfs_do_snapshot(int argc, char **argv)
 {
 	int ret = 0;
-	signed char c;
+	int c;
 	nvlist_t *props;
 	snap_cbdata_t sd = { 0 };
 	boolean_t multiple_snaps = B_FALSE;
diff --git a/cmd/zpool/zpool_main.c b/cmd/zpool/zpool_main.c
index 5d31914764..2cb6774b9a 100644
--- a/cmd/zpool/zpool_main.c
+++ b/cmd/zpool/zpool_main.c
@@ -973,7 +973,7 @@ zpool_do_remove(int argc, char **argv)
 	int i, ret = 0;
 	zpool_handle_t *zhp = NULL;
 	boolean_t stop = B_FALSE;
-	char c;
+	int c;
 	boolean_t noop = B_FALSE;
 	boolean_t parsable = B_FALSE;
 
diff --git a/cmd/zstreamdump/zstreamdump.c b/cmd/zstreamdump/zstreamdump.c
index ed88729b51..a162eceda5 100644
--- a/cmd/zstreamdump/zstreamdump.c
+++ b/cmd/zstreamdump/zstreamdump.c
@@ -237,7 +237,7 @@ main(int argc, char *argv[])
 	struct drr_write_embedded *drrwe = &thedrr.drr_u.drr_write_embedded;
 	struct drr_object_range *drror = &thedrr.drr_u.drr_object_range;
 	struct drr_checksum *drrc = &thedrr.drr_u.drr_checksum;
-	char c;
+	int c;
 	boolean_t verbose = B_FALSE;
 	boolean_t very_verbose = B_FALSE;
 	boolean_t first = B_TRUE;