dopefish.de

This little script takes an IP or hostname as a parameter, and if there is an offending key in the .ssh/known_hosts it removes it and replaces it with the current valid one useful if you are moving/reinstalling a large amount of servers …

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#!/bin/bash
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#===============================================================================
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#          FILE:  ssh-cleankey.sh
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#         USAGE:  ./ssh-cleankey.sh <ip|hostname>
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# 
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#   DESCRIPTION:  deletes stale ssh known_hosts entries
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#===============================================================================
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# true or fasle
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VERBOSE=false
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#=== Exit codes ================================================================
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# 1 - Not a valid IP or not reachable
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#===============================================================================
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#===  FUNCTION  ================================================================
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#          NAME:  print_help
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#   DESCRIPTION:  Prints help and exits
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#===============================================================================
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print_help() { #{{{
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	echo "Usage: `basename $0` <ip|hostname>"
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	echo ""
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	echo "e.g. ./`basename $0` 1.2.3.4"
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	echo ""
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	exit 0
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} #}}}
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if [[ $# -eq 1 ]]
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then
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	HOST="${1}"
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else
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	print_help
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fi
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ping -w1 -c1 $HOST >/dev/null 2>&1
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if [[ $? != 0 ]]
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then
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	$VERBOSE && echo "ERROR: $HOST is either not a valid IP/hostname, or is not reachable via ping"
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	exit 1
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fi
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Check=$(ssh -o connecttimeout=10 -o stricthostkeychecking=no $HOST true 2>&1|grep -c "Offending key")
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if [[ $Check -gt 0 ]]
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then
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	$VERBOSE && echo "$HOST is stale, updating known_hosts"
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	ssh-keygen -R $HOST >/dev/null 2>&1
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	ssh -o connecttimeout=10 -o stricthostkeychecking=no $HOST true >/dev/null 2>&1
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else
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	$VERBOSE && echo "$HOST is OK"
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fi
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exit 0
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bash

This is more a reminder to myself than anything else … this is small snippet that takes a list of IPs and does a whois on all that aren’t in a RBL

Lets say we have al list of IPs in a file “iplist.txt”:

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12.172.121.171
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24.149.208.68
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38.105.100.9
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58.185.207.86
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61.201.51.66
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64.78.164.169

Snippet that checks the IPs (can of course be easily changed to check IPs that are IN a RBL)

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for ip in $(cat iplist.txt)
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do 
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  test $(/usr/bin/rblcheck -qm ${ip}) && continue || clear 
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  whois $ip 
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  printf "###########################\n##### %15s #####\n###########################\n" "${ip}"
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  read
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done

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bash

We did a bit of hiking through the forest to castle ruins yesterday, here are the pictures …

dsc_4167

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panorama

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castle ruins, hiking, photography

Since the implementation of Arrays in Bash is somewhat lacking compared to higher level programming languages (only one-dimensional), and hash lists require a bit of work to set up, you may run into a situation where you have a small list of key/value pairs that are both variable and you need to store.
There are various solutions for the problem, e.g. creating two arrays (one for the keys, one for the values, and combining them by using the same index values for the entries), or using the functions from the link above to build a hash list. For me the easiest way to solve the problem, if I only have a few variables and don’t want to bloat the code, is to (mis)use declare. declare is intended for setting the type of a variable (constant, array, integer,…), but has the nice side affect that you can use variables in the key name, and you can set the value of the variable.

usage:

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declare ${Key}=${Value}

Example:
$File_Config is variable holding the name of a configfile, the content of the file could look like this:

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foo:one
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bar:three
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foobar:bignumber

Snippet:

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if [[ -e "${File_Config}" ]]
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then
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  while read line
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  do
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    Key="${line%%:*}" # chop off everything after the first :
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    Value="${line#*:}" # chop off everything before the first : 
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    Value="$(echo ${Value}|sed 's#^ +##g;s# +$##g')" # chop off any excess whitespace
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    if [[ "${Key}" != "" && "${Value}" != "" ]] # only continue if we have something to do
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    then
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      declare Configuration_${Key}="${Value}"
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    fi
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  done < "${File_Config}"
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fi

after the snippet has read the configfile, you can use $Configuration_foo, $Configuration_bar and $Configuration_foobar in your script. The keynames could also have came from a mysql query, array, command line args, …

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bash