Add -I, an option that asks for confirmation once if recursively

removing directories or if more than 3 files are listed in the
command line.

This feature is intended to provide a safe net but not being too
annoying like having "rm -i" for every deleting operations, and
is generally good for both newbies and power users, preventing
them from being so easily run into ``rm -rf /'', ``rm -rf *''
and so forth.

Originally implemented by Matthew Dillon for DragonFly, plus
some improvements done by various DragonFly contributors.

Approved by:	murray (mentor; the original dillon's version)
Discussed with:	des
Obtained from:	DragonFly's bin/rm/
		rm.c rev. 1.4 - 1.8
		rm.1 rev. 1.3 - 1.4
MFC After:	1 month

2 files changed, 70 insertions, 5 deletions

diff --git a/bin/rm/rm.1 b/bin/rm/rm.1
index c31ecaa..5fb6f05 100644
--- a/bin/rm/rm.1
+++ b/bin/rm/rm.1
@@ -31,7 +31,7 @@
 .\"	@(#)rm.1	8.5 (Berkeley) 12/5/94
 .\" $FreeBSD$
 .\"
-.Dd October 4, 2004
+.Dd October 28, 2004
 .Dt RM 1
 .Os
 .Sh NAME
@@ -40,7 +40,7 @@
 .Nd remove directory entries
 .Sh SYNOPSIS
 .Nm
-.Op Fl dfiPRrvW
+.Op Fl dfiIPRrvW
 .Ar
 .Nm unlink
 .Ar file
@@ -76,6 +76,12 @@ The
 option overrides any previous
 .Fl f
 options.
+.It Fl I
+Request confirmation once if more then three files are being removed or if a
+directory is being recursively removed.  This is a far less intrusive option
+than
+.Fl i
+yet provides almost the same level of protection against mistakes.
 .It Fl P
 Overwrite regular files before deleting them.
 Files are overwritten three times, first with the byte pattern 0xff,
diff --git a/bin/rm/rm.c b/bin/rm/rm.c
index c313282..52ead50 100644
--- a/bin/rm/rm.c
+++ b/bin/rm/rm.c
@@ -58,9 +58,11 @@ __FBSDID("$FreeBSD$");
 #include <unistd.h>
 
 int dflag, eval, fflag, iflag, Pflag, vflag, Wflag, stdin_ok;
+int rflag, Iflag;
 uid_t uid;
 
 int	check(char *, char *, struct stat *);
+int	check2(char **);
 void	checkdot(char **);
 void	checkslash(char **);
 void	rm_file(char **);
@@ -78,7 +80,7 @@ void	usage(void);
 int
 main(int argc, char *argv[])
 {
-	int ch, rflag;
+	int ch;
 	char *p;
 
 	/*
@@ -102,7 +104,7 @@ main(int argc, char *argv[])
 	}
 
 	Pflag = rflag = 0;
-	while ((ch = getopt(argc, argv, "dfiPRrvW")) != -1)
+	while ((ch = getopt(argc, argv, "dfiIPRrvW")) != -1)
 		switch(ch) {
 		case 'd':
 			dflag = 1;
@@ -115,6 +117,9 @@ main(int argc, char *argv[])
 			fflag = 0;
 			iflag = 1;
 			break;
+		case 'I':
+			Iflag = 1;
+			break;
 		case 'P':
 			Pflag = 1;
 			break;
@@ -148,6 +153,10 @@ main(int argc, char *argv[])
 	if (*argv) {
 		stdin_ok = isatty(STDIN_FILENO);
 
+		if (Iflag) {
+			if (check2(argv) == 0)
+				exit (1);
+		}
 		if (rflag)
 			rm_tree(argv);
 		else
@@ -489,6 +498,56 @@ checkslash(char **argv)
 	}
 }
 
+int
+check2(char **argv)
+{
+	struct stat st;
+	int first;
+	int ch;
+	int fcount = 0;
+	int dcount = 0;
+	int i;
+	const char *dname = NULL;
+
+	for (i = 0; argv[i]; ++i) {
+		if (lstat(argv[i], &st) == 0) {
+			if (S_ISDIR(st.st_mode)) {
+				++dcount;
+				dname = argv[i];    /* only used if 1 dir */
+			} else {
+				++fcount;
+			}
+		}
+	}
+	first = 0;
+	while (first != 'n' && first != 'N' && first != 'y' && first != 'Y') {
+		if (dcount && rflag) {
+			fprintf(stderr, "recursively remove");
+			if (dcount == 1)
+				fprintf(stderr, " %s", dname);
+			else
+				fprintf(stderr, " %d dirs", dcount);
+			if (fcount == 1)
+				fprintf(stderr, " and 1 file");
+			else if (fcount > 1)
+				fprintf(stderr, " and %d files", fcount);
+		} else if (dcount + fcount > 3) {
+			fprintf(stderr, "remove %d files", dcount + fcount);
+		} else {
+			return(1);
+		}
+		fprintf(stderr, "? ");
+		fflush(stderr);
+
+		first = ch = getchar();
+		while (ch != '\n' && ch != EOF)
+			ch = getchar();
+		if (ch == EOF)
+			break;
+	}
+	return (first == 'y' || first == 'Y');
+}
+
 #define ISDOT(a)	((a)[0] == '.' && (!(a)[1] || ((a)[1] == '.' && !(a)[2])))
 void
 checkdot(char **argv)
@@ -519,7 +578,7 @@ usage(void)
 {
 
 	(void)fprintf(stderr, "%s\n%s\n",
-	    "usage: rm [-f | -i] [-dPRrvW] file ...",
+	    "usage: rm [-f | -i] [-dIPRrvW] file ...",
 	    "       unlink file");
 	exit(EX_USAGE);
 }