diff --git a/usr.sbin/pw/psdate.c b/usr.sbin/pw/psdate.c
index f8b1fce894b4..f97253b40a86 100644
--- a/usr.sbin/pw/psdate.c
+++ b/usr.sbin/pw/psdate.c
@@ -43,9 +43,9 @@ a2i(char const ** str)
 	int             i = 0;
 	char const     *s = *str;
 
-	if (isdigit(*s)) {
+	if (isdigit((unsigned char)*s)) {
 		i = atoi(s);
-		while (isdigit(*s))
+		while (isdigit((unsigned char)*s))
 			++s;
 		*str = s;
 	}
@@ -55,10 +55,10 @@ a2i(char const ** str)
 static int
 numerics(char const * str)
 {
-	int             rc = isdigit(*str);
+	int             rc = isdigit((unsigned char)*str);
 
 	if (rc)
-		while (isdigit(*str) || *str == 'x')
+		while (isdigit((unsigned char)*str) || *str == 'x')
 			++str;
 	return rc && !*str;
 }
@@ -72,15 +72,15 @@ aindex(char const * arr[], char const ** str, int len)
 	mystr[len] = '\0';
 	l = strlen(strncpy(mystr, *str, len));
 	for (i = 0; i < l; i++)
-		mystr[i] = (char) tolower(mystr[i]);
+		mystr[i] = (char) tolower((unsigned char)mystr[i]);
 	for (i = 0; arr[i] && strcmp(mystr, arr[i]) != 0; i++);
 	if (arr[i] == NULL)
 		i = -1;
 	else {			/* Skip past it */
-		while (**str && isalpha(**str))
+		while (**str && isalpha((unsigned char)**str))
 			++(*str);
 		/* And any following whitespace */
-		while (**str && (**str == ',' || isspace(**str)))
+		while (**str && (**str == ',' || isspace((unsigned char)**str)))
 			++(*str);
 	}			/* Return index */
 	return i;
@@ -143,7 +143,7 @@ parse_datesub(char const * str, int *day, int *mon, int *year)
 
 	while (*str && strchr(nchrs + 10, *str) != NULL)
 		++str;
-	if (isdigit(*str)) {
+	if (isdigit((unsigned char)*str)) {
 		*year = atoi(str);
 		if (*year > 1900)
 			*year -= 1900;
@@ -176,7 +176,7 @@ parse_date(time_t dt, char const * str)
 	if (dt == 0)
 		dt = time(NULL);
 
-	while (*str && isspace(*str))
+	while (*str && isspace((unsigned char)*str))
 		++str;
 
 	if (numerics(str)) {
@@ -247,7 +247,7 @@ parse_date(time_t dt, char const * str)
 			else {
 				int             j = 1;
 
-				while (q[j] && isupper(q[j]))
+				while (q[j] && isupper((unsigned char)q[j]))
 					++j;
 				if (q[j] == '\0')
 					*q = '\0';
diff --git a/usr.sbin/pw/pw.c b/usr.sbin/pw/pw.c
index 6c070acb2665..5c777836b3b3 100644
--- a/usr.sbin/pw/pw.c
+++ b/usr.sbin/pw/pw.c
@@ -31,6 +31,7 @@ static const char rcsid[] =
 
 #include <err.h>
 #include <fcntl.h>
+#include <locale.h>
 #include <paths.h>
 #include <sys/wait.h>
 #include "pw.h"
@@ -131,6 +132,8 @@ main(int argc, char *argv[])
 	umask(0);		/* We wish to handle this manually */
 	LIST_INIT(&arglist);
 
+	(void)setlocale(LC_TIME, "");
+
 	/*
 	 * Break off the first couple of words to determine what exactly
 	 * we're being asked to do
diff --git a/usr.sbin/pw/pw_group.c b/usr.sbin/pw/pw_group.c
index 6042a683713d..c9af998da2a2 100644
--- a/usr.sbin/pw/pw_group.c
+++ b/usr.sbin/pw/pw_group.c
@@ -88,7 +88,7 @@ pw_group(struct userconf * cnf, int mode, struct cargs * args)
 		if (a_name == NULL)
 			errx(EX_DATAERR, "group name or id required");
 
-		if (mode != M_ADD && grp == NULL && isdigit(*a_name->val)) {
+		if (mode != M_ADD && grp == NULL && isdigit((unsigned char)*a_name->val)) {
 			(a_gid = a_name)->ch = 'g';
 			a_name = NULL;
 		}
@@ -220,7 +220,7 @@ pw_group(struct userconf * cnf, int mode, struct cargs * args)
 		for (p = strtok(arg->val, ", \t"); p != NULL; p = strtok(NULL, ", \t")) {
 			int     j;
 			if ((pwd = GETPWNAM(p)) == NULL) {
-				if (!isdigit(*p) || (pwd = getpwuid((uid_t) atoi(p))) == NULL)
+				if (!isdigit((unsigned char)*p) || (pwd = getpwuid((uid_t) atoi(p))) == NULL)
 					errx(EX_NOUSER, "user `%s' does not exist", p);
 			}
 			/*
diff --git a/usr.sbin/pw/pw_log.c b/usr.sbin/pw/pw_log.c
index 6f72c0d2bb05..fc85828b5bbf 100644
--- a/usr.sbin/pw/pw_log.c
+++ b/usr.sbin/pw/pw_log.c
@@ -55,7 +55,8 @@ pw_log(struct userconf * cnf, int mode, int which, char const * fmt,...)
 
 			if ((name = getenv("LOGNAME")) == NULL && (name = getenv("USER")) == NULL)
 				name = "unknown";
-			strftime(nfmt, sizeof nfmt, "%d-%b-%Y %R ", t);
+			/* ISO 8601 International Standard Date format */
+			strftime(nfmt, sizeof nfmt, "%Y-%m-%d %T ", t);
 			l = strlen(nfmt);
 			sprintf(nfmt + strlen(nfmt), "[%s:%s%s] %s\n", name, Which[which], Modes[mode], fmt);
 			va_start(argp, fmt);
diff --git a/usr.sbin/pw/pw_user.c b/usr.sbin/pw/pw_user.c
index b70a4102a521..44290500fc50 100644
--- a/usr.sbin/pw/pw_user.c
+++ b/usr.sbin/pw/pw_user.c
@@ -221,7 +221,7 @@ pw_user(struct userconf * cnf, int mode, struct cargs * args)
 	if ((arg = getarg(args, 'g')) != NULL) {
 		p = arg->val;
 		if ((grp = GETGRNAM(p)) == NULL) {
-			if (!isdigit(*p) || (grp = GETGRGID((gid_t) atoi(p))) == NULL)
+			if (!isdigit((unsigned char)*p) || (grp = GETGRGID((gid_t) atoi(p))) == NULL)
 				errx(EX_NOUSER, "group `%s' does not exist", p);
 		}
 		cnf->default_group = newstr(grp->gr_name);
@@ -234,7 +234,7 @@ pw_user(struct userconf * cnf, int mode, struct cargs * args)
 
 		for (p = strtok(arg->val, ", \t"); p != NULL; p = strtok(NULL, ", \t")) {
 			if ((grp = GETGRNAM(p)) == NULL) {
-				if (!isdigit(*p) || (grp = GETGRGID((gid_t) atoi(p))) == NULL)
+				if (!isdigit((unsigned char)*p) || (grp = GETGRGID((gid_t) atoi(p))) == NULL)
 					errx(EX_NOUSER, "group `%s' does not exist", p);
 			}
 			if (extendarray(&cnf->groups, &cnf->numgroups, i + 2) != -1)
@@ -455,7 +455,7 @@ pw_user(struct userconf * cnf, int mode, struct cargs * args)
 			edited = 1;
 		}
 
-		if ((arg = getarg(args, 'u')) != NULL && isdigit(*arg->val)) {
+		if ((arg = getarg(args, 'u')) != NULL && isdigit((unsigned char)*arg->val)) {
 			pwd->pw_uid = (uid_t) atol(arg->val);
 			edited = 1;
 			if (pwd->pw_uid != 0 && strcmp(pwd->pw_name, "root") == 0)
@@ -827,7 +827,7 @@ pw_gidpolicy(struct userconf * cnf, struct cargs * args, char *nam, gid_t prefer
 	if (a_gid != NULL) {
 		if ((grp = GETGRNAM(a_gid->val)) == NULL) {
 			gid = (gid_t) atol(a_gid->val);
-			if ((gid == 0 && !isdigit(*a_gid->val)) || (grp = GETGRGID(gid)) == NULL)
+			if ((gid == 0 && !isdigit((unsigned char)*a_gid->val)) || (grp = GETGRGID(gid)) == NULL)
 				errx(EX_NOUSER, "group `%s' is not defined", a_gid->val);
 		}
 		gid = grp->gr_gid;
@@ -1078,7 +1078,7 @@ pw_password(struct userconf * cnf, struct cargs * args, char const * user)
 		 * We give this information back to the user
 		 */
 		if (getarg(args, 'h') == NULL && getarg(args, 'N') == NULL) {
-			if (isatty(1))
+			if (isatty(STDOUT_FILENO))
 				printf("Password for '%s' is: ", user);
 			printf("%s\n", pwbuf);
 			fflush(stdout);
@@ -1143,12 +1143,12 @@ print_user(struct passwd * pwd, int pretty, int v7)
 
 			memmove(p + l, p + 1, m);
 			memmove(p, pwd->pw_name, l);
-			*p = (char) toupper(*p);
+			*p = (char) toupper((unsigned char)*p);
 		}
 		if (pwd->pw_expire > (time_t)0 && (tptr = localtime(&pwd->pw_expire)) != NULL)
-		  strftime(acexpire, sizeof acexpire, "%e-%b-%Y %T", tptr);
-		if (pwd->pw_change > (time_t)9 && (tptr = localtime(&pwd->pw_change)) != NULL)
-		  strftime(pwexpire, sizeof pwexpire, "%e-%b-%Y %T", tptr);
+		  strftime(acexpire, sizeof acexpire, "%Ef %Y %X", tptr);
+		if (pwd->pw_change > (time_t)0 && (tptr = localtime(&pwd->pw_change)) != NULL)
+		  strftime(pwexpire, sizeof pwexpire, "%Ef %Y %X", tptr);
 		printf("Login Name: %-15s   #%-12ld Group: %-15s   #%ld\n"
 		       " Full Name: %s\n"
 		       "      Home: %-26.26s      Class: %s\n"
@@ -1176,7 +1176,7 @@ print_user(struct passwd * pwd, int pretty, int v7)
 			}
 		}
 		ENDGRENT();
-		printf("%s\n", j ? "\n" : "");
+		printf("%s", j ? "\n" : "");
 	}
 	return EXIT_SUCCESS;
 }