diff -up mksh/exec.c.fixtrace mksh/exec.c

--- mksh/exec.c.fixtrace	2013-04-26 23:23:09.000000000 +0200

+++ mksh/exec.c	2017-10-10 12:11:30.472249513 +0200

@@ -138,11 +138,6 @@ execute(struct op * volatile t,

 			/* Allow option parsing (bizarre, but POSIX) */

 			timex_hook(t, &up);

 		ap = (const char **)up;

-		if (Flag(FXTRACE)) {

-			shf_puts(substitute(str_val(global("PS4")), 0),

-			    shl_out);

-			Flag(FXTRACE) = 2;

-		}

 		if (ap[0])

 			tp = findcom(ap[0], FC_BI|FC_FUNC);

 	}

@@ -637,6 +632,8 @@ comexec(struct op *t, struct tbl * volat

 	l_assign = e->loc;

 	if (Flag(FEXPORT))

 		type_flags |= EXPORT;

+	if (Flag(FXTRACE))

+		change_xtrace(2, false);

 	for (i = 0; t->vars[i]; i++) {

 		/* do NOT lookup in the new var/fn block just created */

 		e->loc = l_expand;

@@ -650,9 +647,9 @@ comexec(struct op *t, struct tbl * volat

 				++ccp;

 			if (*ccp == '=')

 				++ccp;

-			shf_write(cp, ccp - cp, shl_out);

-			print_value_quoted(shl_out, ccp);

-			shf_putc(' ', shl_out);

+			shf_write(cp, ccp - cp, shl_xtrace);

+			print_value_quoted(shl_xtrace, ccp);

+			shf_putc(' ', shl_xtrace);

 		}

 		/* but assign in there as usual */

 		typeset(cp, type_flags, 0, 0, 0);

@@ -661,17 +658,16 @@ comexec(struct op *t, struct tbl * volat

 	}

 	if (Flag(FXTRACE)) {

+		change_xtrace(2, false);

 		if (ap[rv = 0]) {

  xtrace_ap_loop:

-			print_value_quoted(shl_out, ap[rv]);

+			print_value_quoted(shl_xtrace, ap[rv]);

 			if (ap[++rv]) {

-				shf_putc(' ', shl_out);

+				shf_putc(' ', shl_xtrace);

 				goto xtrace_ap_loop;

 			}

 		}

-		shf_putc('\n', shl_out);

-		Flag(FXTRACE) = 1;

-		shf_flush(shl_out);

+		change_xtrace(1, false);

 	}

 	if ((cp = *ap) == NULL) {

@@ -754,9 +750,9 @@ comexec(struct op *t, struct tbl * volat

 			getopts_reset(1);

 		}

-		old_xflag = Flag(FXTRACE);

-		Flag(FXTRACE) |= tp->flag & TRACE ? 1 : 0;

-

+		old_xflag = Flag(FXTRACE) ? 1 : 0;

+		change_xtrace((Flag(FXTRACEREC) ? old_xflag : 0) |

+		    ((tp->flag & TRACE) ? 1 : 0), false);

 		old_inuse = tp->flag & FINUSE;

 		tp->flag |= FINUSE;

@@ -765,9 +761,11 @@ comexec(struct op *t, struct tbl * volat

 			execute(tp->val.t, flags & XERROK, NULL);

 			i = LRETURN;

 		}

+

 		kshname = old_kshname;

-		Flag(FXTRACE) = old_xflag;

+		change_xtrace(old_xflag, false);

 		tp->flag = (tp->flag & ~FINUSE) | old_inuse;

+

 		/*

 		 * Were we deleted while executing? If so, free the

 		 * execution tree. TODO: Unfortunately, the table entry

@@ -1308,8 +1306,11 @@ iosetup(struct ioword *iop, struct tbl *

 	iotmp.name = (iotype == IOHERE) ? NULL : cp;

 	iotmp.flag |= IONAMEXP;

-	if (Flag(FXTRACE) == 2)

-		fptreef(shl_out, 0, "%R", &iotmp);

+	if (Flag(FXTRACE)) {

+		change_xtrace(2, false);

+		fptreef(shl_xtrace, 0, "%R", &iotmp);

+		change_xtrace(1, false);

+	}

 	switch (iotype) {

 	case IOREAD:

diff -up mksh/main.c.fixtrace mksh/main.c

--- mksh/main.c.fixtrace	2013-05-02 22:22:08.000000000 +0200

+++ mksh/main.c	2013-07-21 20:47:44.000000000 +0200

@@ -332,6 +343,11 @@ main_init(int argc, const char *argv[],

 	 */

 	Flag(FBRACEEXPAND) = 1;

+	/*

+	 * Turn on "set -x" inheritance by default.

+	 */

+	Flag(FXTRACEREC) = 1;

+

 #ifndef MKSH_NO_CMDLINE_EDITING

 	/*

 	 * Set edit mode to emacs by default, may be overridden

@@ -1373,7 +1393,7 @@ initio(void)

 	/* force buffer allocation */

 	shf_fdopen(1, SHF_WR, shl_stdout);

 	shf_fdopen(2, SHF_WR, shl_out);

-	shf_fdopen(2, SHF_WR, shl_spare);

+	shf_fdopen(2, SHF_WR, shl_xtrace);

 #ifdef DF

 	if ((lfp = getenv("SDMKSH_PATH")) == NULL) {

 		if ((lfp = getenv("HOME")) == NULL || *lfp != '/')

diff -up mksh/misc.c.fixtrace mksh/misc.c

--- mksh/misc.c.fixtrace	2013-05-02 22:22:09.000000000 +0200

+++ mksh/misc.c	2017-10-10 12:11:30.472249513 +0200

@@ -229,8 +229,12 @@ void

 change_flag(enum sh_flag f, int what, bool newset)

 {

 	unsigned char oldval;

-	unsigned char newval;

+	unsigned char newval = (newset ? 1 : 0);

+	if (f == FXTRACE) {

+		change_xtrace(newval, true);

+		return;

+	}

 	oldval = Flag(f);

 	Flag(f) = newval = (newset ? 1 : 0);

 #ifndef MKSH_UNEMPLOYED

@@ -286,6 +290,37 @@ change_flag(enum sh_flag f, int what, bo

 	}

 }

+void

+change_xtrace(unsigned char newval, bool dosnapshot)

+{

+	if (!dosnapshot && newval == Flag(FXTRACE))

+		return;

+

+	if (Flag(FXTRACE) == 2) {

+		shf_putc('\n', shl_xtrace);

+		Flag(FXTRACE) = 1;

+		shf_flush(shl_xtrace);

+	}

+

+	if (!dosnapshot && Flag(FXTRACE) == 1)

+		switch (newval) {

+		case 1:

+			return;

+		case 2:

+			goto changed_xtrace;

+		}

+

+	shf_flush(shl_xtrace);

+	if (shl_xtrace->fd != 2)

+		close(shl_xtrace->fd);

+	if (!newval || (shl_xtrace->fd = savefd(2)) == -1)

+		shl_xtrace->fd = 2;

+

+ changed_xtrace:

+	if ((Flag(FXTRACE) = newval) == 2)

+		shf_puts(substitute(str_val(global("PS4")), 0), shl_xtrace);

+}

+

 /*

  * Parse command line and set command arguments. Returns the index of

  * non-option arguments, -1 if there is an error.

@@ -444,8 +479,10 @@ parse_args(const char **argv,

 	    (argv[go.optind][0] == '-' || argv[go.optind][0] == '+') &&

 	    argv[go.optind][1] == '\0') {

 		/* lone - clears -v and -x flags */

-		if (argv[go.optind][0] == '-')

-			Flag(FVERBOSE) = Flag(FXTRACE) = 0;

+		if (argv[go.optind][0] == '-') {

+			Flag(FVERBOSE) = 0;

+			change_xtrace(0, false);

+		}

 		/* set skips lone - or + option */

 		go.optind++;

 	}

diff -up mksh/sh_flags.h.fixtrace mksh/sh_flags.h

--- mksh/sh_flags.h.fixtrace	2013-05-02 22:28:40.000000000 +0200

+++ mksh/sh_flags.h	2017-10-10 12:11:30.472249513 +0200

@@ -45,6 +45,9 @@ FN("gmacs", FGMACS, 0, OF_ANY)

 /* ./.	reading EOF does not exit */

 FN("ignoreeof", FIGNOREEOF, 0, OF_ANY)

+/* ./.	inherit -x flag */

+FN("inherit-xtrace", FXTRACEREC, 0, OF_ANY)

+

 /* -i	interactive shell */

 FN("interactive", FTALKING, 'i', OF_CMDLINE)

diff -up mksh/sh.h.fixtrace mksh/sh.h

--- mksh/sh.h.fixtrace	2013-05-03 00:00:17.000000000 +0200

+++ mksh/sh.h	2017-10-10 12:11:30.472249513 +0200

@@ -837,7 +837,7 @@ struct temp {

  * stdio and our IO routines

  */

-#define shl_spare	(&shf_iob[0])	/* for c_read()/c_print() */

+#define shl_xtrace	(&shf_iob[0])	/* for set -x */

 #define shl_stdout	(&shf_iob[1])

 #define shl_out		(&shf_iob[2])

 #ifdef DF

@@ -1905,6 +1905,7 @@ void initctypes(void);

 size_t option(const char *);

 char *getoptions(void);

 void change_flag(enum sh_flag, int, bool);

+void change_xtrace(unsigned char, bool);

 int parse_args(const char **, int, bool *);

 int getn(const char *, int *);

 int gmatchx(const char *, const char *, bool);