"net-snmp-create-v3-user" script for Ubuntu 14.04 (forgotten by the Ubuntu package mantainers)

net-snmp-create-v3-user

#!/bin/sh
#
# $Id$
#
# this shell script is designed to add new SNMPv3 users
# to Net-SNMP config file.
 
prefix=/usr
exec_prefix=/usr
includedir=/usr/include
libdir=/usr/lib64
datarootdir=${prefix}/share
NSC_LDFLAGS="-Wl,-z,relro -Wl,-z,now"
NSC_INCLUDEDIR=${includedir}
NSC_LIBDIR=-L${libdir}
NSC_LIBS=""
NSC_AGENTLIBS=" -Wl,-E -Wl,-rpath,/usr/lib64/perl5/CORE"
NSC_PREFIX=$prefix
NSC_EXEC_PREFIX=$exec_prefix
NSC_SRCDIR=.
NSC_INCDIR=${NSC_PREFIX}/include
NSC_BASE_SUBAGENT_LIBS="-lnetsnmpagent -lnetsnmphelpers -lnetsnmp"
NSC_BASE_AGENT_LIBS="-lnetsnmpagent -lnetsnmphelpers -lnetsnmpmibs -lnetsnmp"
NSC_SRC_LIBDIRS="agent/.libs snmplib/.libs agent/helpers/.libs"
NSC_SRC_LIBDEPS="agent/.libs/libnetsnmpmibs.a agent/.libs/libnetsnmpagent.a agent/helpers/.libs/libnetsnmphelpers.a snmplib/.libs/libnetsnmp.a"
 
if test "x$NSC_SRCDIR" = "x." ; then
   NSC_SRCDIR="NET-SNMP-SOURCE-DIR"
fi
 
if /bin/ps -e | egrep ' snmpd *$' > /dev/null 2>&1 ; then
    echo "Apparently at least one snmpd demon is already running."
    echo "You must stop them in order to use this command."
    exit 1
fi
 
Aalgorithm="MD5"
Xalgorithm="DES"
token=rwuser
 
while test "x$done" = "x" -a "x$1" != "x" -a "x$usage" != "xyes"; do
case "$1" in
    -*=*) optarg=`echo "$1" | sed 's/[-_a-zA-Z0-9]*=//'` ;;
    *) optarg= ;;
esac
 
unset shifted
case $1 in
    --version|--ver*)
      echo 5.5
      ;;
    --help)
      usage="yes"
      ;;
 
    -A|-a)
        shift
        if test "x$1" = "x" ; then
            echo "You must specify an authentication algorithm or pass phrase"
            exit 1
        fi
        case $1 in
            MD5|SHA)
            Aalgorithm=$1
            shift
            ;;
            md5|sha)
            Aalgorithm=`echo $1 | tr a-z A-Z`
            shift
            ;;
            *)
            apassphrase=$1
            shift
            ;;
        esac
        ;;
    -X|-x)
        shift
        if test "x$1" = "x" ; then
            echo "You must specify an encryption algorithm or pass phrase"
            exit 1
        fi
        case $1 in
            DES|AES|AES128)
            Xalgorithm=$1
            shift
            ;;
            des|aes|aes128)
            Xalgorithm=`echo $1 | tr a-z A-Z`
            shift
            ;;
            *)
            xpassphrase=$1
            shift
            ;;
        esac
        ;;
    -ro)
        token="rouser"
        shift
        ;;
    -*)
        echo "unknown suboption to $0: $1"
        usage=yes
        done=1
        ;;
    *)
        done=1
        ;;
    esac
done
 
if test "x$usage" = "xyes"; then
    echo ""
    echo "Usage:"
    echo "  net-snmp-create-v3-user [-ro] [-A authpass] [-X privpass]"
    echo "                          [-a MD5|SHA] [-x DES|AES] [username]"
    echo ""
    exit
fi
 
if test "x$1" = "x" ; then
    prompt=yes
    echo "Enter a SNMPv3 user name to create: "
    read user
else
    user=$1
    shift
fi
if test "x$user" = "x" ; then
    echo "You must specify a user name"
    exit 1
fi
if test "x$apassphrase" = "x" ; then
    prompt=yes
    echo "Enter authentication pass-phrase: "
    read apassphrase
fi
if test "x$apassphrase" = "x" ; then
    echo "You must specify an authentication pass-phrase"
    exit 1
fi
    if test "x$prompt" = "xyes" -a "x$xpassphrase" = "x" ; then
    echo "Enter encryption pass-phrase: "
    echo "  [press return to reuse the authentication pass-phrase]"
    read xpassphrase
fi
outdir="/var/lib/snmp"
outfile="$outdir/snmpd.conf"
line="createUser $user $Aalgorithm \"$apassphrase\" $Xalgorithm $xpassphrase"
echo "adding the following line to $outfile:"
echo "  " $line
# in case it hasn't ever been started yet, start it.
if test ! -d $outdir ; then
    mkdir $outdir
fi
if test ! -d $outfile ; then
    touch $outfile
fi
echo $line >> $outfile
outfile="/etc/snmp/snmpd.conf"
line="$token $user"
echo "adding the following line to $outfile:"
echo "  " $line
if test ! -d $outfile ; then
    touch $outfile
fi
echo $line >> $outfile

Install

In Ubuntu:

wget https://gist.githubusercontent.com/rarylson/72d1414d6907a4548427/raw/d97aed8debf0a291a0457ec634a3be370bd16546/net-snmp-create-v3-user
chmod +x net-snmp-create-v3-user
mv net-snmp-create-v3-user /usr/local/bin

Now, you can run:

net-snmp-config --create-snmpv3-user [...]

This script was based in this pastebin proposed by Wylie (wyl1e).