<p>I had setup my clients &amp; server for passwordless login.
Like passwordless login by copying RSA key of server to all client's /root/.ssh/id-rsa.pub. but this, I have done manually. I like to automate this process using shell script and providing password to the machines through script.
If this problem is solved then I also want to use rsync to automate push items to all servers. 
Can any body help me in this regard.</p>

<p>Thank you</p>

This script comes in Debian (and derivatives) machines, to distribute the keys. It's called ssh-copy-id. You'd use it like this:
```
```
ssh-copy-id [-i identity_file] [user@]machine
```
```
Then you'd enter the password and the copying would be done. You would do this one time only and then could use the rsync over ssh as usual.
```
```
#!/bin/sh

# Shell script to install your identity.pub on a remote machine
# Takes the remote machine name as an argument.
# Obviously, the remote machine must accept password authentication,
# or one of the other keys in your ssh-agent, for this to work.

ID_FILE="${HOME}/.ssh/identity.pub"

if [ "-i" = "$1" ]; then
  shift
  # check if we have 2 parameters left, if so the first is the new ID file
  if [ -n "$2" ]; then
    if expr "$1" : ".*\.pub" ; then
      ID_FILE="$1"
    else
      ID_FILE="$1.pub"
    fi
    shift         # and this should leave $1 as the target name
  fi
else
  if [ x$SSH_AUTH_SOCK != x ] ; then
    GET_ID="$GET_ID ssh-add -L"
  fi
fi

if [ -z "`eval $GET_ID`" ] && [ -r "${ID_FILE}" ] ; then
  GET_ID="cat ${ID_FILE}"
fi

if [ -z "`eval $GET_ID`" ]; then
  echo "$0: ERROR: No identities found" >&2
  exit 1
fi

if [ "$#" -lt 1 ] || [ "$1" = "-h" ] || [ "$1" = "--help" ]; then
  echo "Usage: $0 [-i [identity_file]] [user@]machine" >&2
  exit 1
fi

{ eval "$GET_ID" ; } | ssh $1 "umask 077; test -d .ssh || mkdir .ssh ; cat >> .ssh/authorized_keys" || exit 1

cat <<EOF
Now try logging into the machine, with "ssh '$1'", and check in:

  .ssh/authorized_keys

to make sure we haven't added extra keys that you weren't expecting.

EOF
```
```