ssh-test

#!/bin/bash

#
# Functions
#

function usage_and_exit {
 cat << EOF >&2

Usage: $0 <host-file>

 Show whether it is possible to ssh into hosts listed in <host-file>.
 Hostnames in <host-file> are separated by newlines and have the format:

 [user@]hostname[:port]

 Sample <host-file>:

 example.vm.host.tld
 me@remote.host.tld
 root@bad.host.tld
 deploy@production.live.example:2222
 deploy@staging.live.example:2224

EOF

 exit 1
}

#
# Command line options and arguments parsing
#

while getopts :h opt; do
 case $opt in
 h) usage_and_exit
 ;;
 '?') echo "$0 Invalid option -$OPTARG" >&2
 usage_and_exit
 ;;
 esac
done

shift $((OPTIND - 1)) # remove options, leave arguments

if [ $# -ne 1 ]; then
 usage_and_exit
fi

#
# MAIN
#


# Calculate the longest hostname, to align columns if we can.
longest_hostname=0
for line in $(cat "$1"); do
 length=${#line}
 [ $length -gt $longest_hostname ] && longest_hostname=$length
done

RED='\033[1;31m'
NC='\033[0m' # No Color

for line in $(cat "$1"); do
	host=${line%:*}
	port=${line#*:}
 if [ ! -z "${port##*[!0-9]*}" ]; then
 portarg="-p $port"
 fi
 printf "%${longest_hostname}s ... " $line
 if ssh -q -o BatchMode=yes -o ConnectTimeout=3 $portarg $host exit 2>/dev/null; then
 echo "OK"
 else
 printf "${RED}FAIL${NC}\n"
 fi
done