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Implement two switches:
-n to make a "dry run" (syntax crontab -n foo)
-h to display a help message
Index: cron/crontab.c
===================================================================
--- cron.orig/crontab.c
+++ cron/crontab.c
@@ -46,7 +46,7 @@ static char rcsid[] = "$Id: crontab.c,v
#endif
-enum opt_t { opt_unknown, opt_list, opt_delete, opt_edit, opt_replace };
+enum opt_t { opt_unknown, opt_list, opt_delete, opt_edit, opt_replace, opt_help };
#if DEBUGGING
static char *Options[] = { "???", "list", "delete", "edit", "replace" };
@@ -60,6 +60,7 @@ static char Directory[MAX_FNAME];
static FILE *NewCrontab = NULL;
static int CheckErrorCount;
static int PromptOnDelete;
+static int dry_run;
static enum opt_t Option;
static struct passwd *pw;
static void list_cmd __P((void)),
@@ -79,13 +80,17 @@ static void
usage(msg)
char *msg;
{
- fprintf(stderr, "%s: usage error: %s\n", ProgramName, msg);
- fprintf(stderr, "usage:\t%s [-u user] file\n", ProgramName);
- fprintf(stderr, "\t%s [ -u user ] [ -i ] { -e | -l | -r }\n", ProgramName);
- fprintf(stderr, "\t\t(default operation is replace, per 1003.2)\n");
+ if (strlen(msg) > 0)
+ fprintf(stderr, "%s: usage error: %s\n", ProgramName, msg);
+ fprintf(stderr, "usage:\t%s [-u user] [-n] file\n", ProgramName);
+ fprintf(stderr, "\t%s [ -u user ] [ -i ] { -e | -l | -r }\n\n", ProgramName);
+ fprintf(stderr, "\t-h\t(displays this help message)\n\n");
+ fprintf(stderr, "\tfile\t(default operation is replace, per 1003.2)\n");
+ fprintf(stderr, "\t-n\t(dry run: checks the syntax, then bails out)\n");
+ fprintf(stderr, "\t-u user\t(choose the user whose crontab is touched)\n\n");
fprintf(stderr, "\t-e\t(edit user's crontab)\n");
fprintf(stderr, "\t-l\t(list user's crontab)\n");
- fprintf(stderr, "\t-r\t(delete user's crontab)\n");
+ fprintf(stderr, "\t-r\t(delete user's crontab)\n\n");
fprintf(stderr, "\t-i\t(prompt before deleting user's crontab)\n");
exit(ERROR_EXIT);
}
@@ -133,6 +138,8 @@ main(argc, argv)
switch (Option) {
case opt_list: list_cmd();
break;
+ case opt_help: usage("");
+ break;
case opt_delete: delete_cmd();
break;
case opt_edit: edit_cmd();
@@ -152,9 +159,9 @@ main(argc, argv)
}
#if DEBUGGING
-const char *getoptarg = "u:lerix:";
+const char *getoptarg = "u:hnlerix:";
#else
-const char *getoptarg = "u:leri";
+const char *getoptarg = "u:hnleri";
#endif
static void
@@ -188,6 +195,14 @@ parse_args(argc, argv)
usage("bad debug option");
break;
#endif
+ case 'h':
+ if (Option != opt_unknown)
+ usage("only one operation permitted");
+ Option = opt_help;
+ break;
+ case 'n':
+ dry_run = 1;
+ break;
case 'u':
if (!(pw = getpwnam(optarg)))
{
@@ -916,7 +931,14 @@ replace_cmd() {
return (-1);
}
-
+ if (dry_run) {
+ /* the option switch -n was used. Do not write the crontab file */
+ /* instead display a pleasant message. */
+ fprintf(stderr, "The syntax of the crontab file was successfully checked.\n");
+ fclose(tmp); unlink(tn);
+ return (0);
+ }
+
#ifdef HAS_FCHMOD
if (fchmod(fileno(tmp), 0600) < OK)
#else
Index: cron/crontab.1
===================================================================
--- cron.orig/crontab.1
+++ cron/crontab.1
@@ -22,7 +22,9 @@
.SH NAME
crontab \- maintain crontab files for individual users (Vixie Cron)
.SH SYNOPSIS
-crontab [ \-u user ] file
+crontab [ \-h]
+.br
+crontab [ \-u user ] [\-n] file
.br
crontab [ \-u user ] [ \-i ] { \-e | \-l | \-r }
.SH DESCRIPTION
@@ -62,6 +64,12 @@ user is always allowed to setup a cronta
users may use this command.
.PP
If the
+.I \-h
+option is given,
+.I crontab
+shows a help message and quits immediately.
+.PP
+If the
.I \-u
option is given, it specifies the name of the user whose crontab is to be
used (when listing) or modified (when editing). If this option is not given,
@@ -80,6 +88,13 @@ option for safety's sake.
The first form of this command is used to install a new crontab from some
named file or standard input if the pseudo-filename ``-'' is given.
.PP
+If the
+.I \-n
+option is given, it means "dry run":
+.I crontab
+examines "your" crontab for its syntax, and outputs a success message if
+this syntax is correct, but nothing is written to any crontab.
+.PP
The
.I \-l
option causes the current crontab to be displayed on standard output. See
|
