zsh-workers/9617

Doc/Zsh/options.yo

@@ -533,6 +533,13 @@ of tt(exit) or tt(logout) instead.
 However, ten consecutive EOFs will cause the shell to exit anyway,
 to avoid the shell hanging if its tty goes away.
 )
+pindex(IGNORE_NULLCMD)
+vindex(NULLCMD, ignoring)
+vindex(READNULLCMD, ignoring)
+item(tt(IGNORE_NULLCMD) <C> <K> <S>)(
+The values of tt(NULLCMD) and tt(READNULLCMD) are not used when running
+redirections with no commands (see noderef(Redirection)).
+)
 pindex(INC_APPEND_HISTORY)
 cindex(history, incremental appending to a file)
 item(tt(INC_APPEND_HISTORY))(
@@ -978,6 +985,14 @@ running - that is purely an indicator of whether on not commands are
 em(actually) being read from standard input.
 The value of this option cannot be changed anywhere other than the command line.
 )
+pindex(SH_NULLCMD)
+cindex(sh, redirections with no command)
+cindex(ksh, redirections with no command)
+item(tt(SH_NULLCMD) <K> <S>)(
+If the variable tt(NULLCMD) is unset or if the option tt(IGNORE_NULLCMD) 
+is set, this option make redirections with no command have the
+standard Bourn shell behaviour (see noderef(Redirection)).
+)
 pindex(SH_OPTION_LETTERS)
 cindex(sh, single letter options style)
 cindex(ksh, single letter options style)

Doc/Zsh/redirect.yo

@@ -198,6 +198,8 @@ when tt(MULTIOS) is unset will truncate bar, and write `tt(foo)' into baz.
 sect(Redirections with no command)
 vindex(NULLCMD, use of)
 vindex(READNULLCMD, use of)
+pindex(IGNORE_NULLCMD, use of)
+pindex(SH_NULLCMD, use of)
 If a simple command consists of one or more redirection operators
 and zero or more parameter assignments, but no command name, and the
 parameter tt(NULLCMD) is not set, an error is caused.  If the parameter
@@ -212,6 +214,15 @@ example(< file)
 shows the contents of tt(file) on standard output, with paging if that is a
 terminal.  tt(NULLCMD) and tt(READNULLCMD) may refer to shell functions.
 
-The standard Bourne shell behaviour is obtained by setting tt(NULLCMD) and
+The above default behaviour can be affected by the options
-tt(READNULLCMD) to `tt(:)'.  This is the default when zsh is emulating bf(sh)
+tt(IGNORE_NULLCMD) and tt(SH_NULLCMD).  tt(SH_NULLCMD) forces the Bourne
-or bf(ksh).
+shell behaviour when the parameter tt(NULLCMD) is not set (i.e. the
+implicit command used with the redirections is `tt(:)'), while
+tt(IGNORE_NULLCMD) is used to obtain the same behaviour as if tt(NULLCMD)
+was unset.
+
+The standard Bourne shell behaviour is obtained by setting the options
+tt(IGNORE_NULLCMD) and tt(SH_NULLCMD).  This is the default when zsh is
+emulating bf(sh) or bf(ksh).  The tt(csh) behaviour can be obtained by
+setting only tt(IGNORE_NULLCMD), which is the default when emulating
+bf(csh).

Src/exec.c

@@ -1661,11 +1661,16 @@ execcmd(Estate state, int input, int output, int how, int last1)
 		    } else if (varspc) {
 			nullexec = 2;
 			break;
-		    } else if (!nullcmd || !*nullcmd ||
+		    } else if (((!nullcmd || !*nullcmd || opts[IGNORENULLCMD])
-			       (cflags & BINF_PREFIX)) {
+				&& !opts[SHNULLCMD]) 
+			       ||(cflags & BINF_PREFIX)) {
 			zerr("redirection with no command", NULL, 0);
 			errflag = lastval = 1;
 			return;
+		    } else if (!nullcmd || !*nullcmd || opts[IGNORENULLCMD]) {
+			if (!args)
+			    args = newlinklist();
+			addlinknode(args, dupstring(":"));
 		    } else if (readnullcmd && *readnullcmd &&
 			       ((Redir) peekfirst(redir))->type == READ &&
 			       !nextnode(firstnode(redir))) {

Src/init.c

@@ -659,17 +659,8 @@ setupvals(void)
     mypid = (zlong) getpid();
     term  = ztrdup("");
 
-    /* The following variable assignments cause zsh to behave more *
+    nullcmd     = ztrdup("cat");
-     * like Bourne and Korn shells when invoked as "sh" or "ksh".  *
+    readnullcmd = ztrdup("more");
-     * NULLCMD=":" and READNULLCMD=":"                             */
-
-    if (emulation == EMULATE_KSH || emulation == EMULATE_SH) {
-	nullcmd     = ztrdup(":");
-	readnullcmd = ztrdup(":");
-    } else {
-	nullcmd     = ztrdup("cat");
-	readnullcmd = ztrdup("more");
-    }
 
     /* We cache the uid so we know when to *
      * recheck the info for `USERNAME'     */

Src/options.c

@@ -134,6 +134,7 @@ static struct optname optns[] = {
 {NULL, "hup",		      OPT_EMULATE|OPT_ZSH,	 HUP},
 {NULL, "ignorebraces",	      OPT_EMULATE|OPT_SH,	 IGNOREBRACES},
 {NULL, "ignoreeof",	      0,			 IGNOREEOF},
+{NULL, "ignorenullcmd",	      OPT_EMULATE|OPT_NONZSH,	 IGNORENULLCMD},
 {NULL, "incappendhistory",    0,			 INCAPPENDHISTORY},
 {NULL, "interactive",	      OPT_SPECIAL,		 INTERACTIVE},
 {NULL, "interactivecomments", OPT_BOURNE,		 INTERACTIVECOMMENTS},
@@ -185,6 +186,7 @@ static struct optname optns[] = {
 {NULL, "shfileexpansion",     OPT_EMULATE|OPT_BOURNE,	 SHFILEEXPANSION},
 {NULL, "shglob",	      OPT_EMULATE|OPT_BOURNE,	 SHGLOB},
 {NULL, "shinstdin",	      OPT_SPECIAL,		 SHINSTDIN},
+{NULL, "shnullcmd",           OPT_EMULATE|OPT_BOURNE,	 SHNULLCMD},
 {NULL, "shoptionletters",     OPT_EMULATE|OPT_BOURNE,	 SHOPTIONLETTERS},
 {NULL, "shortloops",	      OPT_EMULATE|OPT_NONBOURNE, SHORTLOOPS},
 {NULL, "shwordsplit",	      OPT_EMULATE|OPT_BOURNE,	 SHWORDSPLIT},

Src/zsh.h

@@ -1301,6 +1301,7 @@ enum {
     HUP,
     IGNOREBRACES,
     IGNOREEOF,
+    IGNORENULLCMD,
     INCAPPENDHISTORY,
     INTERACTIVE,
     INTERACTIVECOMMENTS,
@@ -1352,6 +1353,7 @@ enum {
     SHFILEEXPANSION,
     SHGLOB,
     SHINSTDIN,
+    SHNULLCMD,
     SHOPTIONLETTERS,
     SHORTLOOPS,
     SHWORDSPLIT,