SNMPwalk

NT> snmputil walk "cmd"

After having executed 'snmpwalk cisco-kulak.kuleuven.ac.be > snmpfile', you
now can study the output of snmpwalk (snmpfile).  In every line of snmpfile,
you can read something that looks like this: 

interfaces.ifTable.ifEntry.ifInOctets.1 = Counter: VALUE (e.g.:2332952983)

Example output of snmpwalk

Suppose you need the value of this line (VALUE), you can run a script (using
PERL, ...) that executes the following command several times a day with snmpget.

SNMPget

NT> snmputil get "cmd"

'snmpget cisco-kulak.kuleuven.ac.be public
interfaces.ifTable.ifEntry.ifInOctets.1 | cut -f 2 -d = | cut -f 2 -d : >>
file'

Example output of snmpget executed several times.

For those who aren't jet familiar with UNIX or LINUX some explanation is
needed:

* 'snmpget cisco-kulak.kuleuven.ac.be public
interfaces.ifTable.ifEntry.ifInOctets.1': Contacts cisco-kulak.kuleuven.ac.be
and asks for the information about interfaces.ifTable.ifEntry.ifInOctets.1. 
The normal output of this command would be
interfaces.ifTable.ifEntry.ifInOctets.1 = Counter: VALUE (e.g.:2332952983) 
on the screen
 * |: A pipe, takes the output from the previous command (here: 'snmpget 
cisco-kulak.kuleuven.ac.be public interfaces.ifTable.ifEntry.ifInOctets.1')
and feeds it as input to the following command (here: cut).  
* cut -f 2 -d =: divides its input in two colums, separated by the =-sign
(because of -d =) and takes the second column as output (because of -f 2). 
This makes the output of this command 'Counter: VALUE'.
* cut -f 2 -d :: Drops the 'Counter:'
* >> file: takes the output from the previous command and adds it to 'file'. 
Take care to use >> and not >: > overwrites the existing file; >> adds ouput
to file.

This all makes that every time the commando is executed, a line with the value
VALUE is added to 'file'.