how to compare

[munna_dude]

[root@localhost src]# cat /proc/net/dev
Inter-| Receive | Transmit
face |bytes packets errs drop fifo frame compressed multicast|bytes packets errs drop fifo colls carrier compressed
lo: 3679006 16314 0 0 0 0 0 0 3679006 16314 0 0 0 0 0 0
eth0:14562108 62251 0 0 0 0 0 0 7789381 41532 0 0 0 0 0 0
sit0: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
[root@localhost src]# cat /proc/net/dev
Inter-| Receive | Transmit
face |bytes packets errs drop fifo frame compressed multicast|bytes packets errs drop fifo colls carrier compressed
lo: 3679006 16314 0 0 0 0 0 0 3679006 16314 0 0 0 0 0 0
eth0:14562108 62251 0 0 0 0 0 0 7789381 41532 0 0 0 0 0 0
sit0: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

it is fine.
but how can i compare these last two prints of "etho"
that is
eth0:14562108 62251 0 0 0 0 0 0 7789381 41532 0 0 0 0 0 0

eth0:14562108 62251 0 0 0 0 0 0 7789381 41532 0 0 0 0 0 0

the above two lines comes when net is down.
so, how can i compare these two lines programatically
i tried like this

char print()
{

FILE* FD;
char buf[256] = {0};
char buf1[256] = {0};
char buf2[256] = {0};
char buf3[256] = {0};
char* linkstatus = NULL;

FD = popen ("cat /proc/net/dev ", "r");

if (FD)
{
fgets (buf, sizeof (buf), FD);
buf[strlen(buf) - 1] = '\0';
fgets (buf1, sizeof (buf1), FD);
buf1[strlen(buf) - 1] = '\0';
fgets (buf2, sizeof (buf2), FD);
buf2[strlen(buf1) - 1] = '\0';
fgets (buf3, sizeof (buf3), FD);
buf3[strlen(buf2) - 1] = '\0';
linkstatus = strstr (buf3, "eth0");
printf("buf3=%s\n",buf3);
printf("linkstatus=%s\n",linkstatus);
}

pclose (FD);

if (strcmp (linkstatus, ":")!=NULL)
{

printf ("Success \n");

}
else
{
printf ("Unplugged \n");

}
return -1;
}

this code prints only present

i have to store the previous prints also

then ony i can compare prev. eth0
and present eth0

if these are not equal net is up
else net is down

help me in this way

thank you in advance

[munna_dude]

hi

some times it is not showing proper output

i tried like this

[root@localhost ~]# cat /proc/net/dev | grep eth0 | sed 's/^[ \t]*//' | cut -d" " -f2
6052555

some times it has spaces immediately after eth0:
eth0: 6046602 20579 3302 73 1104 0 0 0 307233

some times it may have more one spaces, some times it has no spaces.

can you please help me to get the number immediately after eth0:


thank you in advance