4 files changed, 986 insertions, 1 deletions

diff --git a/procps/Config.in b/procps/Config.in
index 91319103f..b834fbf96 100644
--- a/procps/Config.in
+++ b/procps/Config.in
@@ -43,6 +43,12 @@ config KILLALL5
         default n
         depends on KILL
 
+config NMETER
+        bool "nmeter"
+        default n
+        help
+          Prints selected system stats continuously, one line per update.
+
 config PIDOF
         bool "pidof"
         default n
@@ -130,6 +136,14 @@ config UPTIME
           the system has been running, how many users are currently logged
           on, and the system load averages for the past 1, 5, and 15 minutes.
 
+config WATCH
+        bool "watch"
+        default n
+        #huh?? select DATE
+        help
+          watch is used to execute a program periodically, showing
+          output to the screen.
+
 
 endmenu
 
diff --git a/procps/Kbuild b/procps/Kbuild
index 33f616fc2..c75be291b 100644
--- a/procps/Kbuild
+++ b/procps/Kbuild
@@ -6,12 +6,14 @@
 
 lib-y:=
 lib-$(CONFIG_FREE)      += free.o
+lib-$(CONFIG_FUSER)     += fuser.o
 lib-$(CONFIG_KILL)      += kill.o
 lib-$(CONFIG_ASH)       += kill.o  # used for built-in kill by ash
+lib-$(CONFIG_NMETER)    += nmeter.o
 lib-$(CONFIG_PIDOF)     += pidof.o
 lib-$(CONFIG_PS)        += ps.o
 lib-$(CONFIG_RENICE)    += renice.o
 lib-$(CONFIG_BB_SYSCTL) += sysctl.o
 lib-$(CONFIG_TOP)       += top.o
 lib-$(CONFIG_UPTIME)    += uptime.o
-lib-$(CONFIG_FUSER)     += fuser.o
+lib-$(CONFIG_WATCH)     += watch.o
diff --git a/procps/nmeter.c b/procps/nmeter.c
new file mode 100644
index 000000000..1d58eb2c1
--- /dev/null
+++ b/procps/nmeter.c
@@ -0,0 +1,889 @@
+/*
+** Licensed under the GPL v2, see the file LICENSE in this tarball
+**
+** Based on nanotop.c from floppyfw project
+**
+** Contact me: vda.linux@googlemail.com */
+
+//TODO:
+// simplify code
+// /proc/locks
+// /proc/stat:
+// disk_io: (3,0):(22272,17897,410702,4375,54750)
+// btime 1059401962
+
+#include "libbb.h"
+#include <time.h>
+
+typedef unsigned long long ullong;
+
+enum { PROC_FILE_SIZE = 4096 };
+
+typedef struct proc_file {
+        char *file;
+        //const char *name;
+        smallint last_gen;
+} proc_file;
+
+static const char *const proc_name[] = {
+        "stat",         // Must match the order of proc_file's!
+        "loadavg",
+        "net/dev",
+        "meminfo",
+        "diskstats",
+        "sys/fs/file-nr",
+};
+
+struct globals {
+        // Sample generation flip-flop
+        smallint gen;
+        // Linux 2.6? (otherwise assumes 2.4)
+        smallint is26;
+        // 1 if sample delay is not an integer fraction of a second
+        smallint need_seconds;
+        char *cur_outbuf;
+        const char *final_str;
+        int delta;
+        int deltanz;
+        struct timeval tv;
+#define first_proc_file proc_stat
+        proc_file proc_stat;    // Must match the order of proc_name's!
+        proc_file proc_loadavg;
+        proc_file proc_net_dev;
+        proc_file proc_meminfo;
+        proc_file proc_diskstats;
+        proc_file proc_sys_fs_filenr;
+};
+#define G (*ptr_to_globals)
+#define gen                (G.gen               )
+#define is26               (G.is26              )
+#define need_seconds       (G.need_seconds      )
+#define cur_outbuf         (G.cur_outbuf        )
+#define final_str          (G.final_str         )
+#define delta              (G.delta             )
+#define deltanz            (G.deltanz           )
+#define tv                 (G.tv                )
+#define proc_stat          (G.proc_stat         )
+#define proc_loadavg       (G.proc_loadavg      )
+#define proc_net_dev       (G.proc_net_dev      )
+#define proc_meminfo       (G.proc_meminfo      )
+#define proc_diskstats     (G.proc_diskstats    )
+#define proc_sys_fs_filenr (G.proc_sys_fs_filenr)
+#define INIT_G() do { \
+                PTR_TO_GLOBALS = xzalloc(sizeof(G)); \
+                cur_outbuf = outbuf; \
+                final_str = "\n"; \
+                deltanz = delta = 1000000; \
+        } while (0)
+
+// We depend on this being a char[], not char* - we take sizeof() of it
+#define outbuf bb_common_bufsiz1
+
+static inline void reset_outbuf(void)
+{
+        cur_outbuf = outbuf;
+}
+
+static inline int outbuf_count(void)
+{
+        return cur_outbuf - outbuf;
+}
+
+static void print_outbuf(void)
+{
+        int sz = cur_outbuf - outbuf;
+        if (sz > 0) {
+                xwrite(1, outbuf, sz);
+                cur_outbuf = outbuf;
+        }
+}
+
+static void put(const char *s)
+{
+        int sz = strlen(s);
+        if (sz > outbuf + sizeof(outbuf) - cur_outbuf)
+                sz = outbuf + sizeof(outbuf) - cur_outbuf;
+        memcpy(cur_outbuf, s, sz);
+        cur_outbuf += sz;
+}
+
+static void put_c(char c)
+{
+        if (cur_outbuf < outbuf + sizeof(outbuf))
+                *cur_outbuf++ = c;
+}
+
+static void put_question_marks(int count)
+{
+        while (count--)
+                put_c('?');
+}
+
+static void readfile_z(char *buf, int sz, const char* fname)
+{
+// open_read_close() will do two reads in order to be sure we are at EOF,
+// and we don't need/want that.
+//      sz = open_read_close(fname, buf, sz-1);
+
+        int fd = xopen(fname, O_RDONLY);
+        buf[0] = '\0';
+        if (fd >= 0) {
+                sz = read(fd, buf, sz-1);
+                if (sz > 0) buf[sz] = '\0';
+                close(fd);
+        }
+}
+
+static const char* get_file(proc_file *pf)
+{
+        if (pf->last_gen != gen) {
+                pf->last_gen = gen;
+                // We allocate PROC_FILE_SIZE bytes. This wastes memory,
+                // but allows us to allocate only once (at first sample)
+                // per proc file, and reuse buffer for each sample
+                if (!pf->file)
+                        pf->file = xmalloc(PROC_FILE_SIZE);
+                readfile_z(pf->file, PROC_FILE_SIZE, proc_name[pf - &first_proc_file]);
+        }
+        return pf->file;
+}
+
+static inline ullong read_after_slash(const char *p)
+{
+        p = strchr(p, '/');
+        if (!p) return 0;
+        return strtoull(p+1, NULL, 10);
+}
+
+enum conv_type { conv_decimal, conv_slash };
+
+// Reads decimal values from line. Values start after key, for example:
+// "cpu  649369 0 341297 4336769..." - key is "cpu" here.
+// Values are stored in vec[]. arg_ptr has list of positions
+// we are interested in: for example: 1,2,5 - we want 1st, 2nd and 5th value.
+static int vrdval(const char* p, const char* key,
+        enum conv_type conv, ullong *vec, va_list arg_ptr)
+{
+        int indexline;
+        int indexnext;
+
+        p = strstr(p, key);
+        if (!p) return 1;
+
+        p += strlen(key);
+        indexline = 1;
+        indexnext = va_arg(arg_ptr, int);
+        while (1) {
+                while (*p == ' ' || *p == '\t') p++;
+                if (*p == '\n' || *p == '\0') break;
+
+                if (indexline == indexnext) { // read this value
+                        *vec++ = conv==conv_decimal ?
+                                strtoull(p, NULL, 10) :
+                                read_after_slash(p);
+                        indexnext = va_arg(arg_ptr, int);
+                }
+                while (*p > ' ') p++; // skip over value
+                indexline++;
+        }
+        return 0;
+}
+
+// Parses files with lines like "cpu0 21727 0 15718 1813856 9461 10485 0 0":
+// rdval(file_contents, "string_to_find", result_vector, value#, value#...)
+// value# start with 1
+static int rdval(const char* p, const char* key, ullong *vec, ...)
+{
+        va_list arg_ptr;
+        int result;
+
+        va_start(arg_ptr, vec);
+        result = vrdval(p, key, conv_decimal, vec, arg_ptr);
+        va_end(arg_ptr);
+
+        return result;
+}
+
+// Parses files with lines like "... ... ... 3/148 ...."
+static int rdval_loadavg(const char* p, ullong *vec, ...)
+{
+        va_list arg_ptr;
+        int result;
+
+        va_start(arg_ptr, vec);
+        result = vrdval(p, "", conv_slash, vec, arg_ptr);
+        va_end(arg_ptr);
+
+        return result;
+}
+
+// Parses /proc/diskstats
+//   1  2 3   4  5        6(rd)  7      8     9     10(wr) 11     12 13     14
+//   3  0 hda 51292 14441 841783 926052 25717 79650 843256 3029804 0 148459 3956933
+//   3  1 hda1 0 0 0 0 <- ignore if only 4 fields
+static int rdval_diskstats(const char* p, ullong *vec)
+{
+        ullong rd = 0; // to avoid "warning: 'rd' might be used uninitialized"
+        int indexline = 0;
+        vec[0] = 0;
+        vec[1] = 0;
+        while (1) {
+                indexline++;
+                while (*p == ' ' || *p == '\t') p++;
+                if (*p == '\0') break;
+                if (*p == '\n') {
+                        indexline = 0;
+                        p++;
+                        continue;
+                }
+                if (indexline == 6) {
+                        rd = strtoull(p, NULL, 10);
+                } else if (indexline == 10) {
+                        vec[0] += rd;  // TODO: *sectorsize (don't know how to find out sectorsize)
+                        vec[1] += strtoull(p, NULL, 10);
+                        while (*p != '\n' && *p != '\0') p++;
+                        continue;
+                }
+                while (*p > ' ') p++; // skip over value
+        }
+        return 0;
+}
+
+static void scale(ullong ul)
+{
+        char buf[5];
+        smart_ulltoa5(ul, buf);
+        put(buf);
+}
+
+
+#define S_STAT(a) \
+typedef struct a { \
+        struct s_stat *next; \
+        void (*collect)(struct a *s); \
+        const char *label;
+#define S_STAT_END(a) } a;
+
+S_STAT(s_stat)
+S_STAT_END(s_stat)
+
+static void collect_literal(s_stat *s)
+{
+}
+
+static s_stat* init_literal(void)
+{
+        s_stat *s = xmalloc(sizeof(s_stat));
+        s->collect = collect_literal;
+        return (s_stat*)s;
+}
+
+static s_stat* init_delay(const char *param)
+{
+        delta = bb_strtoi(param, NULL, 0) * 1000;
+        deltanz = delta > 0 ? delta : 1;
+        need_seconds = (1000000%deltanz) != 0;
+        return NULL;
+}
+
+static s_stat* init_cr(const char *param)
+{
+        final_str = "\r";
+        return (s_stat*)0;
+}
+
+
+//     user nice system idle  iowait irq  softirq (last 3 only in 2.6)
+//cpu  649369 0 341297 4336769 11640 7122 1183
+//cpuN 649369 0 341297 4336769 11640 7122 1183
+enum { CPU_FIELDCNT = 7 };
+S_STAT(cpu_stat)
+        ullong old[CPU_FIELDCNT];
+        int bar_sz;
+        char *bar;
+S_STAT_END(cpu_stat)
+
+
+static void collect_cpu(cpu_stat *s)
+{
+        ullong data[CPU_FIELDCNT] = { 0, 0, 0, 0, 0, 0, 0 };
+        unsigned frac[CPU_FIELDCNT] = { 0, 0, 0, 0, 0, 0, 0 };
+        ullong all = 0;
+        int norm_all = 0;
+        int bar_sz = s->bar_sz;
+        char *bar = s->bar;
+        int i;
+
+        if (rdval(get_file(&proc_stat), "cpu ", data, 1, 2, 3, 4, 5, 6, 7)) {
+                put_question_marks(bar_sz);
+                return;
+        }
+
+        for (i = 0; i < CPU_FIELDCNT; i++) {
+                ullong old = s->old[i];
+                if (data[i] < old) old = data[i];               //sanitize
+                s->old[i] = data[i];
+                all += (data[i] -= old);
+        }
+
+        if (all) {
+                for (i = 0; i < CPU_FIELDCNT; i++) {
+                        ullong t = bar_sz * data[i];
+                        norm_all += data[i] = t / all;
+                        frac[i] = t % all;
+                }
+
+                while (norm_all < bar_sz) {
+                        unsigned max = frac[0];
+                        int pos = 0;
+                        for (i = 1; i < CPU_FIELDCNT; i++) {
+                                if (frac[i] > max) max = frac[i], pos = i;
+                        }
+                        frac[pos] = 0;  //avoid bumping up same value twice
+                        data[pos]++;
+                        norm_all++;
+                }
+
+                memset(bar, '.', bar_sz);
+                memset(bar, 'S', data[2]); bar += data[2]; //sys
+                memset(bar, 'U', data[0]); bar += data[0]; //usr
+                memset(bar, 'N', data[1]); bar += data[1]; //nice
+                memset(bar, 'D', data[4]); bar += data[4]; //iowait
+                memset(bar, 'I', data[5]); bar += data[5]; //irq
+                memset(bar, 'i', data[6]); bar += data[6]; //softirq
+        } else {
+                memset(bar, '?', bar_sz);
+        }
+        put(s->bar);
+}
+
+
+static s_stat* init_cpu(const char *param)
+{
+        int sz;
+        cpu_stat *s = xmalloc(sizeof(cpu_stat));
+        s->collect = collect_cpu;
+        sz = strtol(param, NULL, 0);
+        if (sz < 10) sz = 10;
+        if (sz > 1000) sz = 1000;
+        s->bar = xmalloc(sz+1);
+        s->bar[sz] = '\0';
+        s->bar_sz = sz;
+        return (s_stat*)s;
+}
+
+
+S_STAT(int_stat)
+        ullong old;
+        int no;
+S_STAT_END(int_stat)
+
+static void collect_int(int_stat *s)
+{
+        ullong data[1];
+        ullong old;
+
+        if (rdval(get_file(&proc_stat), "intr", data, s->no)) {
+                put_question_marks(4);
+                return;
+        }
+
+        old = s->old;
+        if (data[0] < old) old = data[0];               //sanitize
+        s->old = data[0];
+        scale(data[0] - old);
+}
+
+static s_stat* init_int(const char *param)
+{
+        int_stat *s = xmalloc(sizeof(int_stat));
+        s->collect = collect_int;
+        if (param[0]=='\0') {
+                s->no = 1;
+        } else {
+                int n = strtoul(param, NULL, 0);
+                s->no = n+2;
+        }
+        return (s_stat*)s;
+}
+
+
+S_STAT(ctx_stat)
+        ullong old;
+S_STAT_END(ctx_stat)
+
+static void collect_ctx(ctx_stat *s)
+{
+        ullong data[1];
+        ullong old;
+
+        if (rdval(get_file(&proc_stat), "ctxt", data, 1)) {
+                put_question_marks(4);
+                return;
+        }
+
+        old = s->old;
+        if (data[0] < old) old = data[0];               //sanitize
+        s->old = data[0];
+        scale(data[0] - old);
+}
+
+static s_stat* init_ctx(const char *param)
+{
+        ctx_stat *s = xmalloc(sizeof(ctx_stat));
+        s->collect = collect_ctx;
+        return (s_stat*)s;
+}
+
+
+S_STAT(blk_stat)
+        const char* lookfor;
+        ullong old[2];
+S_STAT_END(blk_stat)
+
+static void collect_blk(blk_stat *s)
+{
+        ullong data[2];
+        int i;
+
+        if (is26) {
+                i = rdval_diskstats(get_file(&proc_diskstats), data);
+        } else {
+                i = rdval(get_file(&proc_stat), s->lookfor, data, 1, 2);
+                // Linux 2.4 reports bio in Kbytes, convert to sectors:
+                data[0] *= 2;
+                data[1] *= 2;
+        }
+        if (i) {
+                put_question_marks(9);
+                return;
+        }
+
+        for (i=0; i<2; i++) {
+                ullong old = s->old[i];
+                if (data[i] < old) old = data[i];               //sanitize
+                s->old[i] = data[i];
+                data[i] -= old;
+        }
+        scale(data[0]*512); // TODO: *sectorsize
+        put_c(' ');
+        scale(data[1]*512);
+}
+
+static s_stat* init_blk(const char *param)
+{
+        blk_stat *s = xmalloc(sizeof(blk_stat));
+        s->collect = collect_blk;
+        s->lookfor = "page";
+        return (s_stat*)s;
+}
+
+
+S_STAT(fork_stat)
+        ullong old;
+S_STAT_END(fork_stat)
+
+static void collect_thread_nr(fork_stat *s)
+{
+        ullong data[1];
+
+        if (rdval_loadavg(get_file(&proc_loadavg), data, 4)) {
+                put_question_marks(4);
+                return;
+        }
+        scale(data[0]);
+}
+
+static void collect_fork(fork_stat *s)
+{
+        ullong data[1];
+        ullong old;
+
+        if (rdval(get_file(&proc_stat), "processes", data, 1)) {
+                put_question_marks(4);
+                return;
+        }
+
+        old = s->old;
+        if (data[0] < old) old = data[0];       //sanitize
+        s->old = data[0];
+        scale(data[0] - old);
+}
+
+static s_stat* init_fork(const char *param)
+{
+        fork_stat *s = xmalloc(sizeof(fork_stat));
+        if (*param == 'n') {
+                s->collect = collect_thread_nr;
+        } else {
+                s->collect = collect_fork;
+        }
+        return (s_stat*)s;
+}
+
+
+S_STAT(if_stat)
+        ullong old[4];
+        const char *device;
+        char *device_colon;
+S_STAT_END(if_stat)
+
+static void collect_if(if_stat *s)
+{
+        ullong data[4];
+        int i;
+
+        if (rdval(get_file(&proc_net_dev), s->device_colon, data, 1, 3, 9, 11)) {
+                put_question_marks(10);
+                return;
+        }
+
+        for (i=0; i<4; i++) {
+                ullong old = s->old[i];
+                if (data[i] < old) old = data[i];               //sanitize
+                s->old[i] = data[i];
+                data[i] -= old;
+        }
+        put_c(data[1] ? '*' : ' ');
+        scale(data[0]);
+        put_c(data[3] ? '*' : ' ');
+        scale(data[2]);
+}
+
+static s_stat* init_if(const char *device)
+{
+        if_stat *s = xmalloc(sizeof(if_stat));
+
+        if (!device || !device[0])
+                bb_show_usage();
+        s->collect = collect_if;
+
+        s->device = device;
+        s->device_colon = xmalloc(strlen(device)+2);
+        strcpy(s->device_colon, device);
+        strcat(s->device_colon, ":");
+        return (s_stat*)s;
+}
+
+
+S_STAT(mem_stat)
+        char opt;
+S_STAT_END(mem_stat)
+
+// "Memory" value should not include any caches.
+// IOW: neither "ls -laR /" nor heavy read/write activity
+//      should affect it. We'd like to also include any
+//      long-term allocated kernel-side mem, but it is hard
+//      to figure out. For now, bufs, cached & slab are
+//      counted as "free" memory
+//2.6.16:
+//MemTotal:       773280 kB
+//MemFree:         25912 kB - genuinely free
+//Buffers:        320672 kB - cache
+//Cached:         146396 kB - cache
+//SwapCached:          0 kB
+//Active:         183064 kB
+//Inactive:       356892 kB
+//HighTotal:           0 kB
+//HighFree:            0 kB
+//LowTotal:       773280 kB
+//LowFree:         25912 kB
+//SwapTotal:      131064 kB
+//SwapFree:       131064 kB
+//Dirty:              48 kB
+//Writeback:           0 kB
+//Mapped:          96620 kB
+//Slab:           200668 kB - takes 7 Mb on my box fresh after boot,
+//                            but includes dentries and inodes
+//                            (== can take arbitrary amount of mem)
+//CommitLimit:    517704 kB
+//Committed_AS:   236776 kB
+//PageTables:       1248 kB
+//VmallocTotal:   516052 kB
+//VmallocUsed:      3852 kB
+//VmallocChunk:   512096 kB
+//HugePages_Total:     0
+//HugePages_Free:      0
+//Hugepagesize:     4096 kB
+static void collect_mem(mem_stat *s)
+{
+        ullong m_total = 0;
+        ullong m_free = 0;
+        ullong m_bufs = 0;
+        ullong m_cached = 0;
+        ullong m_slab = 0;
+
+        if (rdval(get_file(&proc_meminfo), "MemTotal:", &m_total, 1)) {
+                put_question_marks(4);
+                return;
+        }
+        if (s->opt == 'f') {
+                scale(m_total << 10);
+                return;
+        }
+
+        if (rdval(proc_meminfo.file, "MemFree:", &m_free  , 1)
+         || rdval(proc_meminfo.file, "Buffers:", &m_bufs  , 1)
+         || rdval(proc_meminfo.file, "Cached:",  &m_cached, 1)
+         || rdval(proc_meminfo.file, "Slab:",    &m_slab  , 1)
+        ) {
+                put_question_marks(4);
+                return;
+        }
+
+        m_free += m_bufs + m_cached + m_slab;
+        switch (s->opt) {
+        case 'f':
+                scale(m_free << 10); break;
+        default:
+                scale((m_total - m_free) << 10); break;
+        }
+}
+
+static s_stat* init_mem(const char *param)
+{
+        mem_stat *s = xmalloc(sizeof(mem_stat));
+        s->collect = collect_mem;
+        s->opt = param[0];
+        return (s_stat*)s;
+}
+
+
+S_STAT(swp_stat)
+S_STAT_END(swp_stat)
+
+static void collect_swp(swp_stat *s)
+{
+        ullong s_total[1];
+        ullong s_free[1];
+        if (rdval(get_file(&proc_meminfo), "SwapTotal:", s_total, 1)
+         || rdval(proc_meminfo.file,       "SwapFree:" , s_free,  1)
+        ) {
+                put_question_marks(4);
+                return;
+        }
+        scale((s_total[0]-s_free[0]) << 10);
+}
+
+static s_stat* init_swp(const char *param)
+{
+        swp_stat *s = xmalloc(sizeof(swp_stat));
+        s->collect = collect_swp;
+        return (s_stat*)s;
+}
+
+
+S_STAT(fd_stat)
+S_STAT_END(fd_stat)
+
+static void collect_fd(fd_stat *s)
+{
+        ullong data[2];
+
+        if (rdval(get_file(&proc_sys_fs_filenr), "", data, 1, 2)) {
+                put_question_marks(4);
+                return;
+        }
+
+        scale(data[0] - data[1]);
+}
+
+static s_stat* init_fd(const char *param)
+{
+        fd_stat *s = xmalloc(sizeof(fd_stat));
+        s->collect = collect_fd;
+        return (s_stat*)s;
+}
+
+
+S_STAT(time_stat)
+        int prec;
+        int scale;
+S_STAT_END(time_stat)
+
+static void collect_time(time_stat *s)
+{
+        char buf[sizeof("12:34:56.123456")];
+        struct tm* tm;
+        int us = tv.tv_usec + s->scale/2;
+        time_t t = tv.tv_sec;
+
+        if (us >= 1000000) {
+                t++;
+                us -= 1000000;
+        }
+        tm = localtime(&t);
+
+        sprintf(buf, "%02d:%02d:%02d", tm->tm_hour, tm->tm_min, tm->tm_sec);
+        if (s->prec)
+                sprintf(buf+8, ".%0*d", s->prec, us / s->scale);
+        put(buf);
+}
+
+static s_stat* init_time(const char *param)
+{
+        int prec;
+        time_stat *s = xmalloc(sizeof(time_stat));
+
+        s->collect = collect_time;
+        prec = param[0]-'0';
+        if (prec < 0) prec = 0;
+        else if (prec > 6) prec = 6;
+        s->prec = prec;
+        s->scale = 1;
+        while (prec++ < 6)
+                s->scale *= 10;
+        return (s_stat*)s;
+}
+
+static void collect_info(s_stat *s)
+{
+        gen ^= 1;
+        while (s) {
+                put(s->label);
+                s->collect(s);
+                s = s->next;
+        }
+}
+
+
+typedef s_stat* init_func(const char *param);
+
+static const char options[] = "ncmsfixptbdr";
+static init_func *const init_functions[] = {
+        init_if,
+        init_cpu,
+        init_mem,
+        init_swp,
+        init_fd,
+        init_int,
+        init_ctx,
+        init_fork,
+        init_time,
+        init_blk,
+        init_delay,
+        init_cr,
+};
+
+int nmeter_main(int argc, char **argv);
+int nmeter_main(int argc, char **argv)
+{
+        char buf[32];
+        s_stat *first = NULL;
+        s_stat *last = NULL;
+        s_stat *s;
+        char *cur, *prev;
+
+        INIT_G();
+
+        xchdir("/proc");
+
+        if (argc != 2)
+                bb_show_usage();
+
+        if (open_read_close("version", buf, sizeof(buf)) > 0)
+                is26 = (strstr(buf, " 2.4.")==NULL);
+
+        // Can use argv[1] directly, but this will mess up
+        // parameters as seen by e.g. ps. Making a copy...
+        cur = xstrdup(argv[1]);
+        while (1) {
+                char *param, *p;
+                prev = cur;
+ again:
+                cur = strchr(cur, '%');
+                if (!cur)
+                        break;
+                if (cur[1] == '%') {    // %%
+                        strcpy(cur, cur+1);
+                        cur++;
+                        goto again;
+                }
+                *cur++ = '\0';          // overwrite %
+                if (cur[0] == '[') {
+                        // format: %[foptstring]
+                        cur++;
+                        p = strchr(options, cur[0]);
+                        param = cur+1;
+                        while (cur[0] != ']') {
+                                if (!cur[0])
+                                        bb_show_usage();
+                                cur++;
+                        }
+                        *cur++ = '\0';  // overwrite [
+                } else {
+                        // format: %NNNNNNf
+                        param = cur;
+                        while (cur[0] >= '0' && cur[0] <= '9')
+                                cur++;
+                        if (!cur[0])
+                                bb_show_usage();
+                        p = strchr(options, cur[0]);
+                        *cur++ = '\0';  // overwrite format char
+                }
+                if (!p)
+                        bb_show_usage();
+                s = init_functions[p-options](param);
+                if (s) {
+                        s->label = prev;
+                        s->next = 0;
+                        if (!first)
+                                first = s;
+                        else
+                                last->next = s;
+                        last = s;
+                } else {
+                        // %NNNNd or %r option. remove it from string
+                        strcpy(prev + strlen(prev), cur);
+                        cur = prev;
+                }
+        }
+        if (prev[0]) {
+                s = init_literal();
+                s->label = prev;
+                s->next = 0;
+                if (!first)
+                        first = s;
+                else
+                        last->next = s;
+                last = s;
+        }
+
+        // Generate first samples but do not print them, they're bogus
+        collect_info(first);
+        reset_outbuf();
+        if (delta >= 0) {
+                gettimeofday(&tv, NULL);
+                usleep(delta > 1000000 ? 1000000 : delta - tv.tv_usec%deltanz);
+        }
+
+        while (1) {
+                gettimeofday(&tv, NULL);
+                collect_info(first);
+                put(final_str);
+                print_outbuf();
+
+                // Negative delta -> no usleep at all
+                // This will hog the CPU but you can have REALLY GOOD
+                // time resolution ;)
+                // TODO: detect and avoid useless updates
+                // (like: nothing happens except time)
+                if (delta >= 0) {
+                        int rem;
+                        // can be commented out, will sacrifice sleep time precision a bit
+                        gettimeofday(&tv, NULL);
+                        if (need_seconds)
+                                rem = delta - ((ullong)tv.tv_sec*1000000 + tv.tv_usec) % deltanz;
+                        else
+                                rem = delta - tv.tv_usec%deltanz;
+                        // Sometimes kernel wakes us up just a tiny bit earlier than asked
+                        // Do not go to very short sleep in this case
+                        if (rem < delta/128) {
+                                rem += delta;
+                        }
+                        usleep(rem);
+                }
+        }
+
+        /*return 0;*/
+}
diff --git a/procps/watch.c b/procps/watch.c
new file mode 100644
index 000000000..2ad0564cd
--- /dev/null
+++ b/procps/watch.c
@@ -0,0 +1,80 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Mini watch implementation for busybox
+ *
+ * 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.
+ */
+
+/* BB_AUDIT SUSv3 N/A */
+/* BB_AUDIT GNU defects -- only option -n is supported. */
+
+#include "libbb.h"
+
+// procps 2.0.18:
+// watch [-d] [-n seconds]
+//   [--differences[=cumulative]] [--interval=seconds] command
+//
+// procps-3.2.3:
+// watch [-dt] [-n seconds]
+//   [--differences[=cumulative]] [--interval=seconds] [--no-title] command
+//
+// (procps 3.x and procps 2.x are forks, not newer/older versions of the same)
+
+int watch_main(int argc, char **argv);
+int watch_main(int argc, char **argv)
+{
+        unsigned opt;
+        unsigned period = 2;
+        unsigned cmdlen = 1; // 1 for terminal NUL
+        char *header = NULL;
+        char *cmd;
+        char *tmp;
+        char **p;
+
+        opt_complementary = "-1"; // at least one param please
+        opt = getopt32(argc, argv, "+dtn:", &tmp);
+        //if (opt & 0x1) // -d (ignore)
+        //if (opt & 0x2) // -t
+        if (opt & 0x4) period = xatou(tmp);
+        argv += optind;
+
+        p = argv;
+        while (*p)
+                cmdlen += strlen(*p++) + 1;
+        tmp = cmd = xmalloc(cmdlen);
+        while (*argv) {
+                tmp += sprintf(tmp, " %s", *argv);
+                argv++;
+        }
+        cmd++; // skip initial space
+
+        while (1) {
+                printf("\033[H\033[J");
+                if (!(opt & 0x2)) { // no -t
+                        int width, len;
+                        char *thyme;
+                        time_t t;
+
+                        get_terminal_width_height(STDOUT_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);
+                }
+                fflush(stdout);
+                // TODO: 'real' watch pipes cmd's output to itself
+                // and does not allow it to overflow the screen
+                // (taking into account linewrap!)
+                system(cmd);
+                sleep(period);
+        }
+        return 0; // gcc thinks we can reach this :)
+}