watch.c - ubase - suckless linux base utils
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       ---
       watch.c (1069B)
       ---
            1 /* See LICENSE file for copyright and license details. */
            2 #include <errno.h>
            3 #include <stdio.h>
            4 #include <stdlib.h>
            5 #include <unistd.h>
            6 
            7 #include "util.h"
            8 
            9 static void
           10 usage(void)
           11 {
           12         eprintf("usage: %s [-t] [-n interval] command\n", argv0);
           13 }
           14 
           15 int
           16 main(int argc, char *argv[])
           17 {
           18         char cmd[BUFSIZ];
           19         char *end;
           20         useconds_t interval = 2 * 1E6;
           21         float period;
           22         int i;
           23 
           24         ARGBEGIN {
           25         case 't':
           26                 break;
           27         case 'n':
           28                 period = strtof(EARGF(usage()), &end);
           29                 if (*end != '\0' || errno != 0)
           30                         eprintf("invalid interval\n");
           31                 if (period < 0)
           32                         period = 0.1f;
           33                 interval = period * 1E6;
           34                 break;
           35         default:
           36                 usage();
           37         } ARGEND;
           38 
           39         if (argc < 1)
           40                 usage();
           41 
           42         if (strlcpy(cmd, argv[0], sizeof(cmd)) >= sizeof(cmd))
           43                 eprintf("command too long\n");
           44         for (i = 1; i < argc; i++) {
           45                 if (strlcat(cmd, " ", sizeof(cmd)) >= sizeof(cmd))
           46                         eprintf("command too long\n");
           47                 if (strlcat(cmd, argv[i], sizeof(cmd)) >= sizeof(cmd))
           48                         eprintf("command too long\n");
           49         }
           50 
           51         for (;;) {
           52                 printf("\x1b[2J\x1b[H"); /* clear */
           53                 fflush(NULL);
           54                 system(cmd);
           55                 usleep(interval);
           56         }
           57         return 0;
           58 }