* Copyright (C) 2001 by Michael Habermann <mhabermann@gmx.de>
* Copyrigjt (C) Mar 16, 2003 Manuel Novoa III (mjn3@codepoet.org)
*
- * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
+//config:config WATCH
+//config: bool "watch (4.1 kb)"
+//config: default y
+//config: help
+//config: watch is used to execute a program periodically, showing
+//config: output to the screen.
+
+//applet:IF_WATCH(APPLET(watch, BB_DIR_BIN, BB_SUID_DROP))
+
+//kbuild:lib-$(CONFIG_WATCH) += watch.o
+
+//usage:#define watch_trivial_usage
+//usage: "[-n SEC] [-t] PROG ARGS"
+//usage:#define watch_full_usage "\n\n"
+//usage: "Run PROG periodically\n"
+//usage: "\n -n Loop period in seconds (default 2)"
+//usage: "\n -t Don't print header"
+//usage:
+//usage:#define watch_example_usage
+//usage: "$ watch date\n"
+//usage: "Mon Dec 17 10:31:40 GMT 2000\n"
+//usage: "Mon Dec 17 10:31:42 GMT 2000\n"
+//usage: "Mon Dec 17 10:31:44 GMT 2000"
/* BB_AUDIT SUSv3 N/A */
/* BB_AUDIT GNU defects -- only option -n is supported. */
#include "libbb.h"
+#define ESC "\033"
+
// procps 2.0.18:
// watch [-d] [-n seconds]
// [--differences[=cumulative]] [--interval=seconds] command
// (procps 3.x and procps 2.x are forks, not newer/older versions of the same)
int watch_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
-int watch_main(int argc, char **argv)
+int watch_main(int argc UNUSED_PARAM, char **argv)
{
unsigned opt;
unsigned period = 2;
- unsigned cmdlen;
- char *header = NULL;
+ unsigned width, new_width;
+ char *header;
char *cmd;
- char *tmp;
- char **p;
- opt_complementary = "-1"; // at least one param please
- opt = getopt32(argv, "+dtn:", &tmp);
- //if (opt & 0x1) // -d (ignore)
- //if (opt & 0x2) // -t
- if (opt & 0x4) period = xatou(tmp);
+#if 0 // maybe ENABLE_DESKTOP?
+ // procps3 compat - "echo TEST | watch cat" doesn't show TEST:
+ close(STDIN_FILENO);
+ xopen("/dev/null", O_RDONLY);
+#endif
+
+ // "+": stop at first non-option (procps 3.x only); -n NUM
+ // at least one param
+ opt = getopt32(argv, "^+" "dtn:+" "\0" "-1", &period);
argv += optind;
- p = argv;
- cmdlen = 1; // 1 for terminal NUL
- while (*p)
- cmdlen += strlen(*p++) + 1;
- tmp = cmd = xmalloc(cmdlen);
- while (*argv) {
- tmp += sprintf(tmp, " %s", *argv);
- argv++;
- }
- cmd++; // skip initial space
+ // watch from both procps 2.x and 3.x does concatenation. Example:
+ // watch ls -l "a /tmp" "2>&1" - ls won't see "a /tmp" as one param
+ cmd = *argv;
+ while (*++argv)
+ cmd = xasprintf("%s %s", cmd, *argv); // leaks cmd
+ width = (unsigned)-1; // make sure first time new_width != width
+ header = NULL;
while (1) {
- printf("\033[H\033[J");
+ /* home; clear to the end of screen */
+ printf(ESC"[H" ESC"[J");
if (!(opt & 0x2)) { // no -t
- int width, len;
- char *thyme;
- time_t t;
+ const unsigned time_len = sizeof("1234-67-90 23:56:89");
+
+ // STDERR_FILENO is procps3 compat:
+ // "watch ls 2>/dev/null" does not detect tty size
+ new_width = get_terminal_width(STDERR_FILENO);
+ if (new_width != width) {
+ width = new_width;
+ free(header);
+ header = xasprintf("Every %us: %-*s", period, (int)width, cmd);
+ }
+ if (time_len < width) {
+ strftime_YYYYMMDDHHMMSS(
+ header + width - time_len,
+ time_len,
+ /*time_t*:*/ NULL
+ );
+ }
- get_terminal_width_height(STDIN_FILENO, &width, 0);
- header = xrealloc(header, width--);
- // '%-*s' pads header with spaces to the full width
- snprintf(header, width, "Every %ds: %-*s", period, width, cmd);
- time(&t);
- thyme = ctime(&t);
- len = strlen(thyme);
- if (len < width)
- strcpy(header + width - len, thyme);
- puts(header);
+ // compat: empty line between header and cmd output
+ printf("%s\n\n", header);
}
- fflush(stdout);
+ fflush_all();
// TODO: 'real' watch pipes cmd's output to itself
// and does not allow it to overflow the screen
// (taking into account linewrap!)